Manual on Efficient Lighting

MANUAL OF PRACTICE ON

EFFICIENT LIGHTING

i

Philippine Copyright 2007

by

Department of Energy (DOE), Philippines All rights in this manual are reserved. No copyright is claimed to the portions of the manual containing copies of the laws, ordinances, regulations, administrative orders or similar documents issued by government or public authorities. All other portions of the manual are covered by copyright. Reproduction of the other portions of the manual covered by copyright shall require the consent of the Department of Energy, Philippines.

First Printing, December 2007

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Republic of the Philippines DEPARTMENT OF ENERGY Energy Center, Merritt Rd., Fort Bonifacio, Taguig

MESSAGE

With climate change already affecting our lives, there is a need to actively involve industry practitioners in implementing energy efficient lighting systems (EELs). By implementing EELs all over the country, we can defer the capacity installation of new power plants. From an economic point of view, it is more affordable to conserve energy than to build another power plant.

The purpose of this guideline is to provide a reference to students and lighting designers and other professionals in the industry in designing and implementing energy efficient lighting systems within the workplace. This booklet will serve as another milestone for the government in its attempt to address climate change through energy efficient lighting.

I am confident that with our concerted efforts, we will be able to

reach our objective of conserving energy, and in doing so, mitigate the destructive effects of climate change.

Angelo T. Reyes

Secretary

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P R E F A C E

In the past years since the IIEE-ELI Manual of Practice on Efficient Lighting herein referred to as Manual has been first published, there has been a remarkable progress in the science and art of efficient lighting design. New and more efficient light sources, improved luminaires and controls, and new standards of efficient lighting practices, have opened up a number of areas that need to be considered in efficient lighting design and practices. In this edition, we have re-organized the order of the chapters in order for the readers to have a smooth flow of ideas. Also, the Committee deemed it necessary to update pertinent Tables and informations to conform with the standards set by the Philippine National Standards (PNS) and other recognized international standards. New technologies such as the T8 and T5 fluorescent lamps were introduced in certain Chapters of the Manual. Also, a section on Obstrusive (Stray) Lighting has been integrated in Chapter 8 as additional information regarding the design of area lighting. Furthermore, Chapter 4 – Light Emitting Diode, Chapter 10 – Basic Lighting Energy Audit, and Chapter 11 – Economic Analysis for Lighting are included as new Chapters to adapt to the advancement of efficient lighting design technologies. Illuminations Calculations, which were previously included in the Chapter on Lighting System Design is now regarded as Appendix E while the IES Tables is added to this edition of the Manual as Appendix F. The Institute of Integrated Electrical Engineers of the Philippines, Inc. (IIEE) in cooperation with the Energy Management Association of the Philippines (ENMAP) and the Philippines Lighting Industry Association (PLIA) through the technical assistance provided by the Philippine Efficient Lighting Market Transformation Project (PELMATP) updated this Manual in response to changing times and advancement of technologies. It is the objective of the IIEE that this Manual be used as a reference textbook for students and lighting design and energy utilization

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professionals in the design of lighting systems and/or energy audit of a facility. The publication of this Manual was made possible through the initiative and support of the United Nations Development Programme-Global Environment Facility and administered, executed, and implemented by the Department of Energy. It is IIEE’s hope that the information in this Manual will provide useful advice, tools and pointers as well as additional resources in order to optimize quality and efficiency in lighting design throughout the country. While every attempt was made and efforts were exerted to ensure the accuracy of the information in this manual, comments regarding omissions and errors are most welcome and highly appreciated.

IIEE STANDARDS COMMITTEE Ad Hoc Subcommittee on Efficient Lighting

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ACKNOWLEDGEMENT

The “MANUAL OF PRACTICE ON EFFICIENT LIGHTING”, was

hewed from a noble objective to reduce greenhouse emissions coming

from the electricity sectors by building and accelerating demand for

energy efficient lighting products. Its development as a printed

publication was a collaborative effort among professional, business and

international organizations that espouse the environmental preservation

and safety as a principle of responsible business and/or professional

practice.

In the course of its conceptualization and production, which spanned

more than a year, the following distinguished entities and individuals

have generously lent their critical participation, assistance, facilities and

support towards the successful completion and release of this manual.

In particular, special thanks to the following individuals who in their

individual capacities contributed significantly to the project: Mr. Leo S.

Cabasag, 2006 IIEE National President, Mr. Virgilio C. Flordeliza, 2005

IIEE National President, and the 2005 & 2006 IIEE National Board of

Governors for their insightful approval to engage the Institute in this

noble project; IIEE Ad Hoc Committee on Efficient Lighting

Chairperson, Engr. Arthur A. Lopez for his able stewardship of the group

tasked to update and develop the Manual of Practice on Efficient

Lighting. Dir. Raquel S. Huliganga (PELMATP Project Director), Engr.

Noel N. Verdote (PELMATP-Project Manager), Atty. Mayla Fermin A.

Ibañez (PELMATP Task Specialist on Policy & Environmental

Management), and Engr. Arturo M. Zabala (PELMATP-Energy Efficient

Lighting System Specialist) for their supports, efforts, and advices. Also,

to our partner in the Technical Assistance, the Philippine Lighting

Industry Association (PLIA), and the Energy Efficientcy Practitioners

Association of the Philippines (EEPAP) for the inputs and technical

expertise that their members extended and most especially to the United

Nations Development Programme for funding the project as a gift for the

Filipino people.

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IIEE Ad Hoc Committee on Efficient Lighting members, Messrs. Arjun

G. Ansay, Konrad Chua, Paul Fung, Jaime Jimenez, Clifford Jison,

Francis Mapile, Ernesto Payongayong, Adam Pineda, Charlie A.

Quirante, Genesis Ramos, Mike Rizarri, Jesus Santos, Ronald

Tahanlangit, Gem Tan, Gideon Tan, Willington KKC Tan, Jake Velasco,

Andrew Yan, Franco Yap, and Arturo Zabala.

Moreover, we would also like to recognize the support and participation

of the following organizations through their representatives, in the

development of this manual: Department of Energy (DOE), Philippine

Lighting Industry Association (PLIA), Department of Trade and Industry

(DTI), Integrated Research and Training Center – Technological

University of the Philippines (IRTC-TUP), Manila Electric Company

(MERALCO), and the Philippine Efficient Lighting Market

Transformation Project Management Office (PELMATP-PMO).

The MANUAL OF PRACTICE ON EFFICIENT LIGHTING is a

fusion of experience, knowledge, and expertise from the country’s

leading technical minds with the world’s latest lighting industry

standards. As such, Filipino technical and engineering practitioners

would now have an authoritative and world-class reference guide for

efficient and environmentally safe lighting specifications and procedures.

In considering the coming up of this publication as a success in itself, the

faithful and widespread compliance by lighting engineers and specifiers

throughout the country as to the information contained herein would be

the ultimate success for all of us who are involved in this project.

Thank you very much.

IIEE STANDARDS COMMITTEE

Ad Hoc Subcommittee on Efficient Lighting

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FOREWORD

It is with sheer delight that I heed the invitation of the Institute of

Integrated Electrical Engineers of the Philippines, Inc. (IIEE) to welcome

you to this updated edition of the IIEE-ELI Manual of Practice on

Efficient Lighting. Not only am I gratified by another opportunity to

serve the cause of global energy efficiency, for which I continue to

pursue with relentless passion, but I just as well posthumously honor the

man who wrote the foreword of the maiden edition, Douglas Leon

Kuffel1 – a colleague who believed with me that God, humankind and

Mother Earth can be served by a seemingly unrelated achievement such

as co-founding the Philippine Lighting Industry Association, Inc. (PLIA)

in November 2001.

As in the pioneer edition, this revised manual takes you through a tour of

useful information on energy-efficient lighting – from the fundamental

sciences behind lighting to cutting-edge technologies awaiting full

commercialization in the global, regional and Philippine lighting

markets. This book should appeal to a wider readership ranging from

lighting design professionals, procurement practitioners, policymakers,

building end-users, lighting industry players, distribution utilities, to

engineering and architectural faculty and students.

Before one immerses into the deeply technical discussions, one must

dare ask – why all the trouble of transforming markets towards energy-

efficient lighting?

The technological advances of this world have driven humanity to

depend on artificial lighting – in fact, way too much dependent. To light

up the world with electricity (that is, excluding the 2 billion people still

using fuel-based lighting), it has been estimated that 2,106,000,000,000

kilowatt-hours/year of electric energy consumption and

21,103,000,000,000,000,000 joules of electric energy production would

1 Douglas Leon Kuffel (1950-2004), Founding Trustee and President of the

Philippine Lighting Industry Association, Inc. (PLIA)

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be needed for lighting alone2 – the equivalent of 1,000 power plants!

This means that, from electric lighting alone, the world emits an

additional 2,893,000,000 tons of CO2 annually from the combustion of

fossil fuels in the generation side of the world’s power sector. It is

likewise estimated that humankind foots an annual energy bill of $232

billion for lighting up the world.3

In the Philippines, the Department of Energy (DOE) estimates that at

least 154,000,000,000 kilowatt-hours will be needed in the next decade

as baseline electricity consumption for end-use lighting.4 This means

that, unless the market transforms fast enough, the country may

contribute as much as 84,546,000 tons of CO2 in greenhouse gas

emissions during the same 10-year period. If we include the 5 million

Filipinos dependent on fuel-based lighting, the Philippines spends over P

80 billion/year for lighting energy.5

The case for efficient lighting market transformation is solid and crystal

clear. The universality of lighting across all sectors and socio-economic

classifications allows all players in each economy to generate savings in

energy expenditures, enhance energy security, and contribute to global

efforts to slow down global warming with greenhouse gas abatement

strategies.

This book enables the lighting user and practitioner to be a catalyzing

force that accelerates the obsolescence of inefficient lighting

technologies and the commercialization of more energy-efficient lighting

technologies. On the premise that the light output is maintained in the

process, the savings potential of the technological shifts recommended in

this manual starts at a low of 15% to a high of 80%.6

2 Evan Mills, Lawrence Berkeley National Laboratory paper for the International

Energy Agency and the Fifth International Conference on Energy-Efficient

Lighting, Nice, France, 2002. 3 2002 estimate of Evan Mills includes both electric and fuel-based lighting. 4 UNDP-DOE baseline estimates, 2003. 5 Author’s estimate. 6 Eighty percent savings are attainable with the replacement of incandescent

bulbs with appropriately rated, quality compact fluorescent lamps.

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Because the development, updating and publication of this manual are

enabling activities, this reference book becomes a power legacy tool of

the Global Environment Facility – initially through the Efficient Lighting

Initiative of the International Finance Corporation7, and now through the

Philippine Efficient Lighting Market Transformation Project8

(PELMATP) of the United Nations Development Programme, the DOE

and the strong partnership with non-governmental organizations such as

the IIEE, PLIA and the Energy Management Association of the

Philippines.

Long after foreign-assisted interventions are closed, this book will be

among those legacy tools that will maintain the momentum of the market

transformation in the years and years to come. By your conscious desire

to use the technical information gathered in this manual, you have

unknowingly chosen to serve as a transformation catalyst, an agent of

change.

Alexander Ablaza Independent Consultant for Energy-Environment & Engineering

Founding Trustee, Philippine Lighting Industry Association, Inc.

11 August 2006, Makati City, Philippines

7 IFC implemented the GEF-assisted program on behalf of the World Bank

Group. 8 This revision of the manual is funded with PELMATP assistance.

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TABLE OF CONTENTS

CHAPTER PAGE 1 Light and Lighting Fundamentals 1.1 Light 1.1.1 Radiant Energy, Light and Color 1.1.2 The Eye and Vision 1.2 Lighting 1.2.1 Lighting Terminologies Introduction 1.2.1.1 Lighting Concepts and Units 1.2.2 Laws for Point Sources of Light 1.2.3 Sources of Artificial Light 1.2.3.1 Introduction 1.2.3.2 Types of Modern Artificial Light Sources 1.2.3.3 Commonly Used Types of Lamps 1.2.3.4 Color Characteristics of Artificial Light Sources 2 Low Intensity Discharge Lamps 2.1 Technical Description 2.1.1 Fluorescent Lamp Operation 2.1.2 Fluorescent Technology 2.1.3 Mercury Reduced Fluorescent Lamps 2.1.4 Operating Parameters 2.2 Linear/Tubular Fluorescent Lamps 2.2.1 Technical Advantages of Triphosphor Lamps 2.2.2 Advantages of Replacing Halophosphor Fluorescent Lamps with Triphosphor Lamps in Existing Systems 2.2.3 The Right Light Color for Every Application 2.2.4 Color Temperature 2.2.5 Environmentally Friendly 2.2.6 Lower Mercury Content 2.2.7 Recyclable Packaging Materials 2.2.8 Recent Products 2.2.9 New Developments and Trends 2.2.10 Efficient Operation of T5 Lamps — With ECGs 2.2.11 Burning Positions 2.2.12 Standard for Linear Fluorescent Lamps 2.3 Compact Fluorescent Lamps

1 1 1 4 6 6 7 9

13 13 14 14

14 21 21 22 25 26 26 31 34

35 37 39 40 40 40 40 43 44 45 45 46

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CHAPTER PAGE 2.3.1 Technology Updates 2.3.2 Current Products 2.3.3 Application Guidelines 2.3.4 Cost Savings Retrofit Profile 2.3.5 Standard for Fluorescent Lamps 2.4 New Technology

2.4.1 Electrodeless (Induction) Lamps 2.5 Guideline Specification 3 High Intensity Discharge (HID) Lamps Introduction

3.1 Technology Description 3.2 Current Products

3.2.1 Metal Halide Lamps 3.2.2 Mercury Lamps 3.2.3 Low-Pressure Sodium Lamps 3.2.4 High Pressure Sodium Lamps 3.2.5 Ballast and Ignitors 3.2.6 Lamp Dimming 3.2.7 Lamp Starting and Restrike 3.2.8 Lamp Life and Failure Modes

3.2.8.1 Metal Halide 3.2.8.2 Standard High-Pressure Sodium 3.2.8.3 Low-Mercury HPS Lamps 3.2.8.4 No-Mercury HPS Lamps

3.2.9 Energy Efficiency 3.2.10 Color Characteristics 3.2.11 Temperature Sensitivity 3.2.12 Burning Orientation 3.2.13 Other Applicable Technologies 3.2.14 HID Ballast 3.2.15 Interchangeable Lamps

3.3 Application Guidelines 3.3.1 Typical Application 3.3.2 Special Application Consideration for HID Lamps

3.4 Example 4 Light-Emitting Diodes

Introductiont

47 55 60 64 66 67 67 69 71 71 71

72 74 80 81 81 84 84 85 86 86 86 86 86 87 88 89 89 89 89 91 91 91

93 93 95 95

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CHAPTER PAGE 4.1 Invention and Development 4.2 How LEDs Work 4.3 Color

4.3.1 Tri-color LEDs 4.3.2 Bi-color LEDs

4.4 Sizes, Shapes and Viewing Angles 4.5 Luminous Flux and Efficacy 4.6 Lumen Depreciation 4.7 Power Source 4.8 Advantages of Using LEDs 4.9 Disadvantages of Using LEDs 4.10 LED Applications 4.11 LEDs: Environmental and Disposal Issues 4.12 LEDs: The Future of Lighting

5 Energy-Efficient Fluorescent Ballast Introduction 5.1 Technology Description

5.1.1 Lamp Ballast 5.1.2 Types of Fluorescent Lamp Ballast 5.1.3 Starting Requirements 5.1.4 Operating Requirements 5.1.5 Lamp and Ballast Wattage Compatibility 5.1.6 Direct Lamp Change Over Using the Existing

Installed Ballast 5.1.7 Efficient and Cost Effective Lamp and Ballast

Changeover 5.1.8 Types of Conventional Ballasts and their

Associated Starting Methods 5.1.9 Other Types of Ballasts and their Associated

Starting Methods 5.1.10 Ballast Factor 5.1.11 Energy Efficiency 5.1.12 Lamp-Ballast System Efficacy 5.1.13 Reliability of Electronic Ballast 5.1.14 Ballast Noise Level (Sounding Rating) 5.1.15 Dimming 5.1.16 Flicker 5.1.17 Harmonics

95 96 97 98 99

100 101 102 102 104 105 105 108 108 109 109 109 109 110 113 113 114

115

115

116

119 122 124 124 125 126 127 128 128

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CHAPTER PAGE 5.1.18 New Generation of High Performance

Electronic Ballast 5.2 Application Guidelines

5.2.1 Electronic Ballast 5.2.2 Ballast Selection Considerations 5.2.3 System Compatibility of Electronic Ballast 5.2.4 Heater Cutout Ballast

5.3 Standard for Electromagnetic Ballast 5.4 Guideline Specifications

6 Lighting Systems and Luminaires 6.1 Lighting Systems 6.2 Luminaires

6.2.1 Definition 6.2.2 Function of Luminaires

6.3 Classification 6.3.1 Classification by Photometric Characteristics 6.3.1.1 CIE Classification 6.3.1.2 NEMA Classification System 6.3.2 IEC Classification System 6.3.2.1 Protection Against Electrical Shock

6.3.2.2 Protection Against Ingress of Dust and Moisture

6.4 Technical Description 6.4.1 Luminaire Components 6.4.2 Light Control Components 6.4.3 Mechanical Components 6.4.4 Electrical Components

6.5 Types of Luminaire Design and Characteristics 6.5.1 General Lighting Luminaire Types 6.5.1.1 Commercial and Residential Luminaire

6.5.1.2 Architectural Luminaires 6.5.1.3 Task Lights 6.5.1.4 Decorative Luminaires 6.5.1.5 Emergency and Exit 6.5.1.6 Industrial Luminaire 6.5.1.7 Outdoor Luminaires 6.5.1.8 Luminaire Design Considerations

6.6 Photometric Data for Luminaires

133 133 134 134 136 136 137 137 139 139 139 139 139 140 140 140 145 146 146

147 149 149 151 155 155 155 156 156 163 166 167 169 170 172 177 181

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CHAPTER PAGE 6.6.1 Light Loss Factor

6.6.2 Overall Light Loss Factor 6.7 Lighting System

6.7.1 Typical Luminaire Installations 6.7.2 Recommended Spacing for General Office Lighting Applications 6.7.3 Recommended Spacing for Other Applications

6.8 Guidelines Specification 6.8.1 Performance Specifications

7 Lighting Control Technologies 7.1 Lighting Control Strategies

7.1.1 Energy Management Strategies 7.2 Lighting Control Techniques

7.2.1 Switching or Dimming 7.2.2 Local or Central

7.2.2.1 Outdoor Luminaires 7.2.2.2 Hardwiring 7.2.2.3 Power Line Carrier 7.2.2.4 Radio Links

7.2.3 Degree of Control Automation and Zoning 7.2.3.1 Zoning

7.3 Lighting Control Equipment 7.3.1 Manual Switching 7.3.2 Timing and Sensing Devices

7.3.2.1 Timing Devices 7.3.2.2 Photo Sensors 7.3.2.3 Occupancy/Motion Sensors

7.4 Impact of Lighting Controls 7.4.1 Electrical Equipment

7.4.1.1 Switching 7.4.1.2 Interference

7.4.2 Power Quality 7.4.3 Human Performance Effects

7.4.3.1 Illumination 7.4.3.2 Audible Noise 7.4.3.3 Flicker 7.4.3.4 Color Changes

7.5 Cost Analysis

184 184 185 187

187 187 192 192 193 193 193 198 198 199 200 200 201 201 201 201 202 202 203 203 204 205 207 208 208 208 209 210 210 210 210 211 211

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CHAPTER PAGE 7.5.1 Cost Considerations

7.5.1.1 Economic Analysis Techniques 7.5.1.2 Sources of Cost and Performance

Data 7.6 Digital Addressable Lighting Interface (DALI)

7.6.1 DALI Advantages to Lighting Designers 7.6.2 DALI Advantages to Facility Managers 7.6.3 DALI Advantages to Building Occupants

8 Lighting System Design Introduction 8.1 Basic Indoor/Interior Lighting Design

8.1.1 Objectives and Design Considerations 8.1.2 Determining Average Illuminance 8.1.3 Indoor Lighting Calculations

8.2 Basic Outdoor/Exterior Lighting Design 8.2.1 Point-by-Point Method 8.2.2 Design Factors 8.2.3 Average Illuminance Equation 8.2.4 Area Design Considerations 8.2.5 Rule of Thumb Method

8.3 Obstrusive (Stray) Lighting 8.3.1 Stray Lighting

8.3.1.1 Sky Glow 8.3.1.2 Light Trespass 8.3.1.3 Glare

8.3.2 Mitigating Obstrusive Light 8.3.2.1 New Lighting Design 8.3.2.2 Existing Lighting Design

Installation 8.4 Computer Aided Lighting Design Softwares

9 Lighting System Maintenance 9.1 Lighting Maintenance

9.1.1 Maintenance Action Checklist 9.2 Maintaining Light

9.2.1 Level Group Relamping 9.2.2 Cleaning 9.2.3 Spot Relamping

9.2.4 Advantage of Group Relamping and Cleaning

212 212

213 213 214 215 215 217 217 217 218 219 230 236 237 238 243 244 247 249 249 249 250 250 250 250

250 251 253 253 253 254 254 254 255 255

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CHAPTER PAGE 9.3 Maintenance Planning

9.4 Troubleshooting and Maintenance Tips 9.4.1 Preheat Fluorescent Lamp Circuits 9.4.2 Rapid-Start Fluorescent Lamp Circuits 9.4.3 Instant-Start Fluorescent Lamp Circuits 9.4.4 Mercury Lamps 9.4.5 Metal Halide Lamps 9.4.6 High-Pressure Sodium Lamps 9.4.7 Low-pressure Sodium Lamps

10 Basic Lighting Energy Audit Introduction

10.1 Definition 10.2 Purpose 10.3 Types of Audit 10.3.1 The Walk-Thru Audit 10.3.2 The Intermediate Audit or Preliminary Audit 10.3.3 The Comprehensive Audit or Detailed Audit 10.4 The Lighting System Auditor 10.5 Evaluating Lighting Systems 10.6 Measuring and Monitoring Equipment Requirement 10.7 Potential of Energy Savings and Payback Period 10.7.1 Simple Payback (SPB) 10.7.2 Life-Cycle Costing (LCC) 10.7.3 Lighting System Cost 10.8 Lighting Audit Report 10.9 Existing Lighting System Conditions 11 Economic Analysis of Lighting

11.1 The Role of Economic Analysis in Lighting 11.2 Lighting Cost Comparisons 11.3 The Cost of Lighting 11.4 Simple Payback 11.5 Simple Rate of Return

11.6 Life-Cycle Cost-Benefit Analysis (LCCBA) 11.6.1 Notes on the LCCBA Worksheet 11.6.2 Financial Equations 11.6.3 Notes on the Use of Equations 11.4 through 11.8 Appendix A Checklist of Energy-Saving Guidelines

255 258 258 259 260 261 263 264 265 267 267 267 268 268 268 269 269 270 270 271 273 273 273 274 275 275 279 279 279 280 282 283 284 286 289

293 295

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CHAPTER PAGE Appendix B Efficient Lighting Initiative (ELI) Voluntary Technical Specification Appendix C Levels of Illumination Currently Recommended Appendix D Metal Halide and High Pressure Sodium (HPS) Lamps Tables Appendix E Illumination Calculations Appendix F Tables Appendix G Ballast Wiring Diagrams

303 313

355 357 397 413

FIGURE PAGE Figure 1.1 The Electromagnetic Spectrum Figure 1.2 Additive Mixing (Light) Figure 1.3 Subtractive Mixing Figure 1.4 The Human Eye Figure 1.5 Rods and Cones in the Retina Figure 1.6 Relative Spectral Sensitivity of the Eye Figure 1.7 Inverse Square Law Figure 1.8 Inverse Square Law — Example Figure 1.9 The Effect Upon the Illuminance When Hitting a Different-Angled Surface Figure 1.10 Inverse Square Law and Cosine Law Figure 1.11 Inverse Law and Cosine Law-Example Figure 1.12 Lamp Families and some Common Lamp Types Figure 2.1 How a Fluorescent Lamp Produces Light Figure 2.2 Relation Between Switching Cycle and Lifetime (CCG) Figure 2.3 Relative Luminous Flux/Ambient Temperature Figure 2.4 Cold Spots Figure 2.5 Fluorescent Lamp Nomenclature Figure 2.6 Lumen Maintenance Figure 2.7 T5 Circular (FC) Lamp Burning Position Figure 2.8 Energy Label for Linear Fluorescent Lamps Figure 2.9 Compact Fluorescent Lamp-Ballast Systems Figure 2.10 Typical Luminous Flux/Temperature Curves for 18W Amalgam CFL

2 3 4 4 5 6 9

10

11 12 12 16 23

28 29 30 32 36 45 46 48

49

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FIGURE PAGE Figure 2.11 Typical Ambient Temperature and Lamp Orientation Effects on Lumen output of Compact Fluorescent Lamps Figure 2.12 Compact Fluorescent Luminaire Application Figure 2.13 Comparison between Incandescent Lamps and CFLs Figure 2.14 Energy Label for Compact Fluorescent Lamps Figure 2.15 Induction (Electrodeless) Lamps Figure 3.1 Metal Halide and High Pressure Sodium Lamp Construction Figure 3.2 Typical HID Lamps Bases and Envelope Share Figure 3.3 Metal Halide Lamp Configurations Figure 3.4 Double—Ended Metal Halide Lamps With FC2 and RSC Bases Figure 3.5 Typical High Pressure Sodium Lamp Configurations Figure 3.6 Life of HID Lamps Figure 3.7 Graphical Comparison of Different Lamp Efficacy Figure 4.1 Light Emitting Diode Anatomy Figure 4.2 LED Structure Figure 4.3 Tri-Color LED Figure 4.4 Bi-Color LED Figure 4.5 LED Shapes Figure 4.6 LED Configuration Figure 4.7 Seven-Segment LED Figure 4.8 Dot Matrix LED Figure 4.9 Exit and Emergency Sign Backlight LED Figure 4.10 Cyclist Belt LED Figure 4.11 LED for Task Lighting Figure 5.1 Typical Electromagnetic Fluorescent Ballast Figure 5.2 Lamp Efficacy vs. Frequency Figure 5.3 A Typical Switch Start Circuit Figure 5.4 Traditional Rapid Start Figure 5.5 Programmed Start with Zero Glow Current Lamp Ballast Compatibility Figure 5.6 Power vs. Ballast Factor Curves for Two-Lamp 1.2m Fluorescent Lamp-Ballast Systems Figure 5.7 Ballast Energy Label

55 57

58 67 68

72 74 76

79

82 87 88 95 97 98 99

101 103 106 107 107 107 108 111 112 117 119

120

123 137

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FIGURE PAGE Figure 6.1 Example of Direct Luminaire Figure 6.2 Example of Semi-direct Lighting Figure 6.3 Example of General-Diffuse Luminaire Figure 6.4 Example of Indirect Luminaire Figure 6.5 Basic Components of Luminaires Figure 6.6 Examples of Reflectors Figure 6.7 Examples of Refractor Figure 6.8 Examples of Diffusers Figure 6.9 Examples of Louvers & Baffles Figure 6.10 Open Direct Luminaire Figure 6.11 Open Luminaire w/ Specular Reflector Figure 6.12 Shield Direct Luminaire Figure 6.13 Shielded Industrial Luminaire Figure 6.14 Typical Four-Lamp Parabolic Troffer Figure 6.15 Example of Troffer with Prismatic Lens Figure 6.16 Indirect Lighting Luminaire Figure 6.17 Cove Lighting System Figure 6.18 HID Indirect Luminaire (Uplighter) Figure 6.19 Direct/Indirect Luminaire Figure 6.20 Example of Stage/Theater Luminaire Figure 6.21 Example of Low Wattage HID Downlight Figure 6.22 Example of Recessed Architectural Downlight Figure 6.23 HID Tracklights and Compact Fluorescent Floodlights Figure 6.24 Screw-in Compact Fluorescent Luminaire Figure 6.25 Typical Compact Fluorescent Task Light Figure 6.26 Compact Fluorescent Wall Sconces Figure 6.27 Decorative Pendant Luminaires Figure 6.28 Examples of Compact Fluorescent Exterior Luminaires Figure 6.29 Examples of Emergency & Exit Lights Figure 6.30 Examples of Linear Fluorescent for Industrial Applications Figure 6.31 Examples of Strip or Batten Luminaires Figure 6.32 Examples of High Bay Luminaires Figure 6.33 Examples of Low Bay Luminaires Figure 6.34 Examples of Floodlights Figure 6.35 Examples of Sportlights

142 142 143 145 150 152 154 154 155 156 157 157 158 160 160 161 162 162 163 163 164 165

165 166 167 168 168

169 170

170 171 171 172 173 173

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FIGURE PAGE Figure 6.36 Examples of Street and Roadway Luminaires Figure 6.37 Example of Pathway Luminaire Figure 6.38 Examples of Garage and Parking Lot Luminaires Figure 6.39 Examples of Security Luminaires Figure 6.40 Examples of Landscape Luminaires Figure 6.41 Measurement of the ‘cold spot’ Temperature for T5 Lamps Figure 6.42 Polar Intensity Diagram Figure 6.42 (a) Dotted Line Figure 6.42 (b) Continuous Line Figure 6.42 Sensitivity of Lamp-Ballast Performance to Ambient Temperature Figure 6.44 Recommended Spacing Figure 6.45 Spacing Requirements for Reasonably Uniform Lighting Figure 6.46 Maximum Spacing Dimensions for Fluorescent Luminaires Figure 6.47 Layout Arrangement for Luminaires Figure 8.1 Light Output Change Due to Voltage Change Figure 8.2 Luminaire Dirt Depreciation (LDD) Factors Figure 8.3 Indoor Lighting Figure 8.4 Room Reflectances Figure 8.5 Room Cavities Figure 8.6 Components of Point-by-Point Method Figure 8.7 Types of Lateral Light Distribution Figure 8.8 Full Cutoff Figure 8.9 Cutoff Figure 8.10 Semi-Cutoff Figure 8.11 Non-Cutoff Figure 8.12 Light Projection Figure 8.13 Interior Poles Figure 8.14 Perimeter Poles Figure 8.15 Graph-Calculations, Rule of Thumb Method

174 175 175 176 176

177 182 183 183

186 188

188

189 191 224 227 230 232 233 238 240 240 241 242 242 245 245 245 248

TABLE PAGE Table 1.1 Lighting Terminologies and Basic Units Table 1.2 Qualitative Comparison of Artificial Light Sources

13

17

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TABLE PAGE Table 2.1 Color of Light and Color Rendering Properties of Fluorescents Table 2.2 Comparison of Standard and Triphosphor Lamps Table 2.3 Appropriate Color Choices by Application Table 2.4 Linear Fluorescent Lamp Comparison (32/36/40W) Table 2.5 Comparative Light Output, Efficacy and Operating Hours of Incandescent Lamps (IL) and Compact Fluorescent Lamps (CFLs) Table 2.6 Residential Applications for Compact Fluorescent Lamps Table 2.7 Commercial Applications for Compact Fluorescent Lamps Table 2.8 Cost/Savings Comparison between Incandescent Lamps and CFL Table 3.1 Color Rendering Index and lamp Efficacy for Typical Light Sources Table 3.2 Typical Application of HID Lamps Table 4.1 Elements Important to the Construction of LEDs Table 4.2 Common Light Emitter Materials and Characteristics Table 4.3 Color Producing Inorganic Semiconductor Materials Table 4.4 Determination of LED Correct Polarity Table 5.1 Ballast Loss Comparison Table 5.2 Effects of Mismatching Ballast and Lamp Types Table 5.3 Example on Cost Effectiveness in Re-Lamping and Use of Electronic Ballast Table 6.1 Protection Degree IP Table 6.2 Luminaires Common IP Rating Table 6.3 Comparative Luminance of Fluorescent Lamps Table 6.4 Technology Design Considerations Table 8.1 Five Degrees of Dirt Conditions Table 8.2 Room Surface Dirt Depreciation (RSDD) Factors Table 8.3 Suggested Mounting Heights Table 10.1 Existing Lighting System Conditions Assessment Worksheet Table 11.1 Lighting Cost Comparison Methods Table 11.2 Worksheet for LCCBA Table 11.3 Conversion Factors for Various Fuels

33 35 37 42

59

61

63

65

73 94 96 98

100 103 111 114

116 148 149 178 179

228 229 246

276 280 284 288

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1

Chapter 1. Light and Lighting Fundamentals

INTRODUCTION

1.1—LIGHT

Light is a form of radiant energy from natural sources (e.g. the sun and stars), and artificial sources (e.g. a candle and electric lamps). It travels in the form of an electromagnetic wave, so it has wavelength and a known speed. Like other electromagnetic radiation, it can be reflected and refracted. Lighting, on the other hand, is the application of light to illuminate objects, surfaces, scenes, pictures and people. Since it is an application, it is both a science and an art. Science, because it makes use of the science of light and employs methods and techniques developed through time. It is an art because the personal taste (preference) and artistic sense of the designer and owner greatly influence the manner by which lighting is applied.

1.1.1 Radiant Energy, Light and Color Light is that portion of the electromagnetic spectrum to which the eye responds. This visible energy is a small part of the total spectrum, which ranges from cosmic rays with extremely short wavelength (1 x 10-14 meter) to electric power frequencies with wavelength in hundred kilometers as shown in Figure 1.1. The visible portion lies between 380 and 770 nanometers (a unit of wavelength equal to 1 x 10-9 meter or one- billionth of a meter). The color of light is determined by its wavelength. Visible energy with the shortest wavelengths (380 to 450 nm) produces the sensation of violet and those with longest wavelengths (630 to 770 nm) produce sensation of red. In between light blue (450 to 490 nm), green (490 to 560 nm), yellow (560 to 590 nm), and orange (590 to 630 nm).

CHAPTER 1. LIGHT AND LIGHTING FUNDAMENTALS

Figure 1.1 The Electromagnetic Spectrum

The region with slightly longer wavelengths immediately adjacent to the red end of the visible spectrum is known as the infrared, and the region with slightly shorter wavelengths immediately adjacent to the violet end of the visible spectrum is the ultraviolet. The human visual system responds to the very small part of the electromagnetic spectrum that lies between 380 and 760 nanometers. However, it does not respond uniformly. Given the same output of power at each wavelength, the visual system will sense the yellow-green region as the brightest and the red and blue region as the darkest. This is why the light source, which has most of its power in the yellow-green area, will have the highest visual efficiency, i.e., the highest lumens per watt.

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However, without a reasonable proportion of red or blue in its output, a light source will not be able to render colors satisfactorily. With most sources, the wider the range of wavelengths present, the lower the efficiency. How to see colors depends on the wavelengths emitted by the light source, the wavelengths reflected by the object, the surroundings in which we see the object and the characteristics of the visual system. Exactly how the visual system really sees color is still only a theory. Lights and pigments mix differently to form colors. The primary colors of light (red, green, and blue) can be added to produce the secondary colors of light–magenta (red plus blue), cyan (green plus blue), and yellow (red plus green). Thus, colors of light are called “additive”. A secondary color of light mixed in the right proportions with its opposite primary will produce white light. Thus, yellow and blue are complimentary colors of light as cyan and red, and magenta and green. In pigments, however, a primary color is defined as one that subtracts or absorbs a primary color of light and reflects or transmits the other two. So the primary colors in pigments (sometimes called subtractive primaries) are magenta, cyan, and yellow – the secondary colors of light.

Figure 1.2 Additive Mixing (Light)

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Figure 1.3 Subtractive Mixing

1.1.2 The Eye and Vision

(a) The Eye. The rays of light enter the eye through the Cornea, which is the transparent membrane that bulges out at the front of the eye. They then pass through the Pupil, which is a round opening in the colored Iris. The eye reduces the size of this opening to limit the rays of light to the central and optically best part of the Lens, except when the full aperture is needed for maximum sensitivity. The pupil also closes for near vision to increase the clarity of near objects. It can change the area of the opening over a ratio of about 16:1 although the eye works efficiently over a range of brightness of about 1,000,000:1. The ability of the eye to adjust to higher or lower levels of luminance is termed Adaption.

Figure 1.4 The Human Eye

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The whole eye is filled with a jelly like substance and the rays pass through this onto the lens, which focuses the image. Muscles around the lens make it fatter or thinner so the eye can focus sharply on distant or close objects. This ability is called Accommodation and ensures that sharp, clear image is focused onto the light sensitive cells of the Retina. We don't "see" with the retina—it is only when the information it collects has been transferred along the Optical Nerve to the brain that a conscious visual image is formed and this is the time we "see".

The retina has two basic types of Receptors—Rods and Cones for

collecting this information. By a chemical process in the retina, the eyes are able to work over the enormous range of brightness we see. Cones can differentiate between the different wavelengths of light and therefore enable us to see in color. The rays of light are not actually colored. The more sensitive rods only give us black and white vision.

Figure 1.5 Rods and Cones in the Retina

(b) Vision. The cones operate during the day and nominal daylight

conditions, and enable us to see in detailed color. This is known as Photopic or daytime Adaptions. The eye is using a mixture of cones and rods to see. If light conditions are not bright, as the rods can only "see" a black and white image, the overall impression is much less brightly colored. This is called Mesopic vision. At even lower levels, much lower than the average street lighting or moonlight, the cones cease to function. The eye losses all its facility to see in color and the rods take over giving completely black and white vision, called Scotopic, or nighttime Adaptions.

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These different adaptions are important because not only does the

eye discriminate between different wavelengths of light with the sensation of color, but it is also more sensitive to some wavelengths than others - and this sensitivity alters between Photopic and Scotopic vision. For Photopic vision, the eye has peak sensitivity at 555 nanometers, which is yellow-green color. However, for Scotopic vision, peak sensitivity moves to 505 nanometers, which is blue-green light, although the vision is in terms of black and white. The Mesopic vision peak will be somewhere between the two.

Figure 1.6 Relative Spectral Sensitivity of the Eye

1.2—LIGHTING

1.2.1 Lighting Terminologies Introduction A basic understanding of lighting fundamentals is essential for specifiers and decision makers who make decisions about lighting design, installation and upgrades. For more detailed terminology used in the lighting industry please refer to the glossary at the end of this manual.

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1.2.1.1 Lighting Concepts and Units

(a) Luminous Flux (Φ). All the radiated power emitted by a light source and perceived by the eye is called luminous flux (Φ) commonly called light output. Unit of measurement is lumen (lm)

LUMINOUS FLUX Is the light output of a light source. Unit: lumen (lm)

(b) Luminous Intensity (I). Generally speaking, a light source

emits its luminous flux (Φ) in different directions and at different intensities. The visible radiant intensity in a particular direction is called luminous intensity (I). The unit of measurement is the candela (cd).

LIGHT INTENSITY

Light intensity is the measure of light output in a specified direction. Unit: candela (cd)

(c) Illuminance (E). Illuminance (E) is a measure of the amount

of light falling on a surface. The distance of the light source from the area being illuminated influences it. An illuminance of 1 lux occurs when a luminous flux of 1 lumen is evenly distributed over an area of 1 square meter. Unit of measurement is lux (lx).

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ILLUMINATION Average illumination of a surface is luminous flux per unit area.

Lux = lumens/m2

(d) Luminance (L). The luminance (L) is the brightness of an

illuminated or luminous surface as perceived by the human eye. Unit of measurement is candelas per square meter (cd/m2).

Illuminated surface

Visible surface

Light intensity

LUMINANCE Is the measure of the brightness of a surface, as seen by the eye. Unit: candela/m2 (cd/m2) Luminance depends on the surface size seen and the light intensity, reflected by the surface towards the eye.

(e) Luminous Efficacy (η). Luminous efficacy indicates the

efficiency with which the electrical power consumed is converted into light. The unit of measurement is lumens per watt (lm/W).

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(f) Luminaire Efficiency. Luminaire efficiency (also known as

the light output ratio) is an important criterion in gauging the energy efficiency of a luminaire. This is the ratio between the luminous flux emitted by the luminaire and the luminous flux of the lamp (or lamps) installed in the luminaire. 1.2.2 Laws for Point Sources of Light The Inverse Square Law and the Cosine Law of Incidence are used to calculate the illuminance at a single point in a plane.

(a) Inverse Square Law. In order to determine the required

illuminance for different task applications, importance is placed in determining the method for calculating this quantity. In the mid-18th century, J. H. Lambert established one of the earliest lighting laws to enable the calculation of illuminance, called the Inverse Square Law (Lambert’s First Law).

To understand this law, consider a cone-shaped beam of light coming

from a small point source and hitting a surface some distance away (see figure below). Suppose that the luminous flux within the cone is one lumen, and that it strikes a surface 1-meter away, producing an illuminated area of 1 square meter. By dividing the luminous flux by the area we can find the illuminance, which will be 1 lux.

Figure 1.7 Inverse Square Law

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From figure above, if the surface is moved further away to a distance of 2 meters, then the luminous flux within the cone will stay the same, but the illuminated area will increase in size to 4 square meters. This will result in an illuminance of 1/4 lux. By doing this, the area has increased in proportion to the square of the distance from the light source, and the illuminance has changed inversely with the square of the distance. If the surface is moved still further away to a distance in 3 meters, the inverse square law operates again. The area has increased in proportion to the distance squared and is now 9 square meters and the resultant illuminance falls inversely to 1/9 lux. All of this is encompassed by the inverse square law, which states that the illuminance E equals I, the intensity of the light source, divided by the distance squared.

I E = —

d2

The LUMINOUS INTENSITY is a measure of how much flux is

emitted within a small conical angle in the direction of the surface and its unit is the CANDELA. If a source emits the same luminous flux in all directions, then the luminous intensity is the same in all directions. For most sources, however, the flux emitted in each direction is not the same.

(a) (b)

Figure 1.8 Inverse Square Law – Example

For example, in Figure 1.8, the luminous intensity of a spotlight

varies with angle. It may have a maximum value of 1000 candelas at the center of the beam. If this spotlight is aimed directly downwards onto the floor 2 meters below [see Figure 1.8(a)], the illuminance will be:

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E = 250 lux

However, if the spotlight is angled [see Figure 1-8(b)] so that the

luminous intensity directed downwards is 100 candelas, the illuminance will now be:

E = 25 lux

(b) Cosine Law. If the surface is turned so that the rays hit it at an

angle, the illuminated area will increase in size and the illuminance will drop accordingly. The ratio of the original illuminated area to the new area is equal to the cosine of the angle through which the surface has been moved. Therefore the illuminance will fall by the factor of the cosine of angle. This is where Lamberts Second Law comes in, the COSINE LAW of illuminance.

If a surface is illuminated to 100 lux and is twisted through an angle

of 60 degrees then the illuminance will fall to half or 50 lux, because the cosine of 60 degrees is ½.

Figure 1.9. The Effect Upon the Illuminance when Hitting a Different-Angled Surface

This cosine law can be combined into one equation with the inverse

square law.

E = Id 2

C o s A

E = 100022 lux

E = 10022 Lux


Figure 1.10 Inverse Square

Lawand Cosine Law

Figure 1.11 Inverse Law and

Cosine Law–Example Returning to the angled spotlight mentioned earlier, if it is 3 meters

above the floor, aiming at a point 3 meters away (see above figures), then its intensity in this direction is 1000 candelas. The distance from the point of illumination to the spotlight is calculated using Pythagorean Theorem and is computed to be 4.24 meters. The light is striking the floor at the angle of 45 degrees so using the combined Inverse Square and cosine law equation, we can calculate the illuminance.

E = Id2 Cos A

1000 4.242 Cos 450=

= 39 lux

These calculations have only referred to one light source but when there are several, the illuminance is calculated in the same way for each source in turn and then these are added together for the total illuminance.

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Table 1.1 Lighting Terminologies and Basic Units

Quantity Quantity is a Measure of

Symbol Unit in SI

Definition of Unit

Luminous intensity (Candlepower)

Ability of source to produce light in a given direction

I Candela (cd)

Approximately equal to the luminous intensity produced by a standard candle

Luminous flux Total amount of light

Ø Lumen (lm)

Luminous flux emitted in a solid angle of 1 steradian by a 1 candela uniform point source

Illuminance (illumination)

Amount of light received on a unit area of surface (density)

E Lux (lx) One lumen equally distributed over one unit area of surface

Luminous exitance

Density of light reflected or transmitted from a surface

M Lm/m2 A surface reflecting or emitting 1 lumen per unit area

Luminance (brightness)

Intensity of light per unit area reflected or transmitted from a surface

L Cd/m2 A surface reflecting or emitting light at the rate of 1 candela per unit of project area

1 meter (m) = 3.28 ft; 1 cd/m2 = 3.14 lm/m2

1m2 = (3.28ft)2 = 10.76 ft2; 1cd/in2 = 452 lm/ft21fc = 10.76 lux 1.2.3 Sources of Artificial Light

1.2.3.1 Introduction

Our prehistoric ancestors burned wood to provide themselves with heat and light. The glowing flame enabled people to live in caves where the rays of the sun never penetrated.

The light of the campfire, the pine torch, and oil and tallow lamps

made a decisive change in the way of life of prehistoric man.

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Since then, chronologically, oil lamps, candles, gas lighting, and

electric lamps have been used for lighting. 1.2.3.2 Types of Modern Artificial Light Sources. Electric light

sources are probably the most commonly used electrical equipment. The primary purpose of the electrical light source is to convert electrical energy into light energy. Commercial, industrial, residential, institutional and other facilities use different light sources. Each lamp type has particular advantages and disadvantages. Selecting the appropriate source depends on installation requirements, life-cycle cost, color qualities, dimming capability, and other required effects.

1.2.3.3 Commonly Used Types of Lamps. Incandescent lamps produce light by the passage of an electric

current through a filament, which heats it to incandescence (e.g. general service, reflectorized, and tungsten-halogen).

Electric discharge lamps produce light by the passage of an electric

current through a vapor or gas, initiating the discharge to fluoresce.

• Low intensity discharge lamp - Fluorescent (tubular, circular, and compact)

• High intensity discharge - Mercury vapor - Metal halide - High pressure sodium - Low pressure sodium

1.2.3.4 Color Characteristics of Artificial Light Sources. White

light is luminous energy containing a mixture of wavelengths that are perceived as color when the eye transforms the energy into a signal for the brain. This mixture determines whether an environment will appear warm or cool and how well people and furnishings will look.

(a) Color and Efficiency. Some lamps are more efficient in

converting energy into visible light than others. The efficacy of lamp refers to the number of lumens leaving the lamp compared to the number

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of watts required by the combination of lamp and ballast. Efficiency or efficacy is expressed in lumens per watt. Sources with higher efficacy require less electrical energy to light a space or area. Thus, for the most efficient lighting, designers should seek the highest efficacy possible for the type of system desired.

(b) Color Rendering. The general expression for the effect of

the light source on the color appearance of objects in conscious or subconscious comparison with their color appearance under a reference light source.

(c) Color Rendering Index (CRI). The measure of the degree

of color shift, which objects undergo when illuminated by the light source, as compared with the color of those same objects when illuminated by a reference source of comparable color temperature.

The CRI uses filament light as a base for 100 and the warm

white fluorescent for 50. Values for common light sources vary from about 20 to 99. The higher the number, the better the color rendering or color appearance (less color shift or distortion occurs).

(d) Color Temperature (Chromaticity). The absolute temperature (in Degrees Kelvin) of a blackbody radiator whose chromaticity nearly resembles that of the light source. This indicates visual “warmth” or “coolness”. The chromaticity of general lighting lamps, measured in Degrees Kelvin (K) falls in the range 2200 to 7500 K. For interior lighting, the chromaticity values of 4000 and above are usually described as “cool”. Around 3500 K, sources have a neutral appearance, but at 3000 and below, the lighting effect is usually judged to be “warm”. Hence, the lower the number, the warmer the light (more red content). The higher the number, the cooler is the light (more blue content).

As with any technology, continuous research is being carried out to improve existing light sources and to develop new ones. In the last 10 years, many new lighting products have been brought to market.

Listed in Table 1.2 is a Qualitative Comparison of Different

Artificial Light Sources. The succeeding Chapters describe the construction, operation and application of these light sources.

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*Although shown in this figure, some lamps are not included in this manual because they are not considered efficient energy-saving lamps.

Figure 1.12 Lamp Families and Some Common Lamp Types

Table 1.2 Qualitative Comparison of Artificial Light Sources Light source Advantages Disadvantages Applications

Incandescent Lamp

(General Service Lamp)

Compact Size No Ballast (no noise or

humming sound) Low initial cost Good optical control (easy to

control light distribution) Good color rendering

(favorable color for humans) Dimmable Good lumen maintenance Light output not affected by

ambient temperature No delay on starting or re-

starting No stroboscopic problems at

60hz

Short life Very low efficacy (lm/W)

Extremely bright point source

High operating temperature*

High infrared component*

Light output affected by voltage variation

*70% Heat and 30% light is produced by the 100% of energy

supplied

They are a good choice for social areas where good rendering and a warm, pleasant, low key effect is desired

Tungsten-Halogen

(Quartz and Iodine Lamp)

Compact size No ballast Good color rendering Moderate life Excellent optical control Dimmable Excellent Lumen Maintenance

Lamp handling is difficult during maintenance

High cost Low efficacy (lm/W) Operating temperature affects lamp life & output

UV output component

For special accent and display lighting in stores and art galleries where good light control is necessary for localized or supplementary lighting, and for decorative lighting.

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Table 1.2 (Continued) Light source Advantages Disadvantages Applications

Fluorescent Lamp

Linear, circular and compact shape

Moderate cost Optical control limited Good efficacy (lm/W) Long lamp life Good color rendition (special color can give excellent color rendering)

Low point brightness Low operating temperature Low infrared output Can be operated with a higher system voltage

Only minor delay on starting and re-starting

Good lumen maintenance Dimmable, with special ballasts

Requires Ballast Stroboscopic effect when used with magnetic ballasts

They are widely used for large area general lighting in offices, commercial establishments and industrial plants

High Intensity Discharge Lamps (HID) general characteristics

High output in compact size Light output not affected by ambient temperature

Can be operated at higher system voltage

Cold weather starting problems

Very bright point source

Stroboscopic effect problem

Long warm-up and re-strike times

Difficult to dim

They are widely used for high bay interior industrial applications, such as street lights, parking lot areas, docks, flood lighting and security lighting, with the development of better color-rendering metal halide lamps, they are now being used with increasing frequency for indoor

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Specific HID types

Mercury Lamp Moderate efficacy Very long life Good lumen maintenance Burning position not critical Dimmable to 25%

Starting takes 3-5 minutes

Does not restart immediately

Has large ballast and may be noisy

Relatively high cost of lamp and ballast

Landscape lighting (greenish appearance)

Metal halide High efficacy Good coloring rendering Medium to long life Good optical control

Variation in color, especially at

end of life (some types)

Dimmable to 60% Burning position very

important With large ballast

and may be noisy High cost of lamp

and ballast Starting takes 2-8

minutes

Retail clothing and furniture stores; warehouses and factories where colors must be perceived correctly.

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High pressure sodium

Very high efficacy Long lamp life Excellent lumen maintenance Good optical control

Poor color rendering Dimmable to 50-60% With large ballast

and may be noisy High cost of lamp

and ballast Starting takes 1-4

minutes.

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Chapter 2. Low Intensity Discharge Lamps

INTRODUCTION

Low intensity discharge lamps or more commonly referred to as fluorescent lamps are among the most widely used light sources in the world because they require little energy to produce a great deal of light. The immense variety of modern luminaires provides a universal basis for the use of fluorescent lamps in the commercial, industrial and residential sectors. Different light colors and different color-rendering levels are available for a whole variety of lighting applications. First introduced in the mid thirties, fluorescent lamps have been developing further ever since. The slimmer 26 mm diameter versions with a new triphosphor coating were introduced in the early eighties and soon superseded the lamps with standard coating on account of their more efficient light and better quality.

2.1—TECHNICAL DESCRIPTION Fluorescent lamps, in common with other discharge lamps, cannot be operated direct from the electrical supply. This is due to the fact that discharge lamps have a NEGATIVE resistance characteristic. Unlike filament lamps, where the current decreases when voltage increases, in a discharge lamp, current INCREASES with an increase in lamp voltage. That means that the lamp will destroy itself if no action is taken to limit the current. Fluorescent lamps have various operating modes, depending on the way the electrodes are brought up to the required operating temperature:

• Current-controlled pre-heating in choke/starter mode, preferred in countries with a high mains voltage (200V or more). Used increasingly in most electronic control gear (ECG).

CHAPTER 2. LOW INTENSITY DISCHARGE LAMPS

• Voltage-controlled pre-heating with additional transformer windings in “rapid start” mode.

• No pre-heating (cold start). This type of starting reduces the lamp life more than any other type and is therefore not recommended for systems with frequent on/off switching.

• Electronic ballasts convert the mains voltage into a high-frequency oscillation of around 35 to 50kHz. As a result, the flickering that may appear as a stroboscopic effect in conjunction with rotating machine parts, for example, is much less noticeable or virtually invisible.

Fluorescent lamp technology has made tremendous advances over the past few years. The trend has been away from high energy consumption lamps to more energy-efficient products, improved color rendition, and a greater selection of color temperatures. These improvements are due in a large part to the use of rare earth phosphors in place of the traditional halophosphors that are used in standard "cool white" lamps. To a lesser degree, efficiency improvements are due to the more widespread use of smaller diameter lamps. The smaller diameter lamps can also increase luminaire efficiency and improve light distribution patterns. Fluorescent Lamps have three designations: Preheat, Rapid Start, and Instant Start. The terminals of Preheat and Rapid Start type lamps are the same: either miniature or medium bi-pin terminals. Instant Start lamps are usually easy to spot, as the terminals are single pins. There are exceptions, but the standard T8 commonly found in the Philippine market is used as if it were any of the above three types (i.e. used in any starting mode). Therefore, users should not mix and match lamps and ballasts without first confirming that the lamp matches the operation mode of the ballast to be connected. Without this confirmation step, it may be possible to experience short life and warranty or safety issues. 2.1.1 Fluorescent Lamp Operation. A fluorescent lamp is a glass tube with the inside surface coated with phosphor. The tube is filled with argon gas, or sometimes with a mixture of argon and krypton. A small amount of mercury is also inside, which is vaporized during lamp operation. Electrodes (also referred to as cathodes) are located at each end of the sealed tube. When a suitable lighting voltage is applied across the electrodes, an electric arc discharge is initiated and the resulting

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current ionizes the vaporized mercury in the tube. The ionized mercury emits ultra-violet (UV) radiation that strikes and excites the phosphor coating on the inside surface of the tube, causing it to glow or fluoresce and produce visible light. The exact makeup of the phosphors coating the tube is what determines the color temperature of the light produced by the lamp.

Figure 2.1 How a Fluorescent Lamp Produces Light

Manufacturers can vary the gas fill, phosphor type and content, as well as the lamp's tube length and diameter, in order to achieve different lamp characteristics. As a result, there is a wide range of lamps being designed and sold. The smallest standard linear fluorescent lamp is the 136 mm, 4-watt, T5 lamp, while the largest lamp is the 2.4 m, 100 watt, T8 lamp. The fluorescent tube is filled with a gas, which, with the addition of mercury, becomes the carrier of the discharge arc; the gas operates at a pressure from 1 to 5 millibar. Mercury is chosen for its ability to create a relatively high gas pressure at low temperatures. This ensures a presence of a large number of mercury atoms in the gas mixture. Mercury also has the advantage in that it does not easily combine with other components used in the discharge process and as a result retains its usefulness over many thousands of hours.

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The cathodes, usually tungsten filaments, at each end of a tube, are coated with an emitter material to aid the emission of electrons. The emitter material consists mainly of alkaline earth oxides. There is one other important point: Electrodes can vary according to the lamp type and may be referred to, for example, as either high resistance or low resistance cathodes. There are three different types of Fluorescent Lamps that are commonly used today. Listed below are the three types and the description for each.

(a) Preheat Operation. Lamp electrodes are heated prior to initiating the discharge. A "starter switch” closes permitting a current to flow through each electrode. The starter switch rapidly cools down, opening the switch, and triggering the supply voltage across the arc tube, initiating the discharge. No auxiliary power is applied across the electrodes during operation.

(b) Instant Start Operation. Lamp electrodes are not heated prior to

operation. Ballasts for instant start lamps are designed to provide a relatively high starting voltage (with respect to preheat and rapid start lamps) to initiate the discharge across the unheated electrodes.

(c) Rapid Start Operation. Lamp electrodes are heated prior to and

during operation. The ballast transformer has two special secondary windings to provide the proper low voltage to the electrodes.

Rapid start is the most popular mode of operation for 1200 mm T-12 40-watt lamps. The advantages of rapid start operation include smooth starting, long life, and dimming capabilities. (Lamps of less than 30 watts are generally operated in the preheat mode. Lamps operated in this mode are more efficient than the rapid start mode as separate power is not required to continuously heat the electrodes. However, these lamps tend to flicker during starting and have a shorter lamp life.) The 1200 mm 32-watt F32T8 and 36-watt F36T8 lamps are a rapid start lamp, but commonly operate instant start mode with electronic high-frequency ballasts. In this mode of operation lamp efficacy is improved with some penalty in lamp life.

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2.1.2 Fluorescent Technology. Discharge lamps cover around 80% of our total artificial lighting needs, with low-pressure mercury discharge lamps, “fluorescent lamps”, making up the bulk (95%) of the discharge family. Naturally, with this prominence, ongoing research is well justified, leading to developments such as:

• The change from T12 (38mm) to T8 (26mm) – reduced materials • Improved phosphors (triphosphor) – better color rendering/longer

life and better lumen maintenance • T5 technology – bringing efficiency levels above 100 lumens per

watt.

(a) Rare Earth (RE) Phosphor Lamps. Rare Earth (RE) phosphor technology improves the performance of fluorescent lamps. RE phosphor compounds are selected for their ability to produce visible light at the most sensitive wavelengths of the eye's red, blue and green sensors. When compared with conventional halophosphors, such as cool white (with a CRI of 60-62), RE phosphors produce better color rendering and higher efficacy, while improving lumen maintenance characteristics. For reasons of lumen maintenance, rare earth materials are required in small diameter lamps, e.g. compact fluorescent and T5.

RE phosphors raise lumen output up to 8% over conventional halophosphors. RE phosphor lamps are available for most fluorescent lamp configurations and are available in a wide range of color temperatures.

(b) Types of Fluorescent Lamps. There are many types of

fluorescent lamps to cater for a wide range of applications. Some require electronic control gear, such as T5 and T2 lamps, while others can be operated on conventional (electromagnetic) control gear or electronic control gear, such as T8 and T12.

The size of tubular fluorescent lamps are often referred to as T2, T5,

T8 or T12, which is an indication of their diameter, such as:

• T12 – 12/8” or 38mm diameter • T10 - 10/8” or 32mm diameter • T8 – 8/8” or 26mm diameter

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• T5 – 5/8” or 16mm diameter • T2 – 2/8” or 7mm diameter

2.1.3 Mercury Reduced Fluorescent Lamps. In recent years improved manufacturing processes have made it possible to reduce the absorption of mercury into the coating and the glass. This in turn was utilized to further reduce the mercury content of fluorescent lamps without compromising lamp starting at low temperatures. The mercury content in different types and brands of lamps varies. The older style T12 (38mm diameter) lamps contain between 15-30mg of mercury, while Standard T8 lamps contain up to 15mg of mercury. All triphosphor-coated lamps now contain approximately 4.5mg (+/- 0.5mg) of mercury against the previous (already reduced) levels of around 8mg. As such, triphosphor and reduced mercury content lamps (T8) are recommended for their contribution to the protection of the environment during disposal. Several countries have already established regulations for the disposal of FL lamps to prevent mercury from being dispersed in the environment we live in. 2.1.4 Operating Parameters

(a) Lamp Life. Lumen Depreciation and Mortality. Depending on the particular issue, we use various definitions of lamp life. The most commonly used term is “Average Life”. Average life is defined as the number of burning hours of a reasonably large sample of lamps at which 50% of the lamps are still operating. This applies for lamps under normal operating conditions at a 3-hour switching cycle as per IEC standards.

Abnormal operating conditions (high or low temperature, high or

low voltage, frequent switching, etc.) may cause premature failures and shorter life of the entire sample of lamps.

There are two different factors, which describe the performance of

fluorescent lamps, namely Lamp Lumen Depreciation (or Lumen Maintenance), and Mortality. Lumen Maintenance describes the reduction of light output over life. Mortality indicates the expected failure rate of lamps.

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The economical life, i.e.: the time after which the lamps have to be

replaced, depends on the maintenance factor in the lighting design calculation. Generally we should replace lamps when the total installed flux has dropped to 80% of the initial flux.

Based on Efficient Lighting Initiative (ELI) Performance

Specifications, the luminous flux of a lamp must be more than 90% of the initial luminous flux level at 40% of the model’s rated lifetime (Please refer to Appendix B2).

(b) Switching Cycles. Switching cycles can have a dramatic effect

on the life of fluorescent lamps. As stated above, the ‘average life’ of fluorescent lamps is based on a 3 hour switching cycle. The graph below (Figure 2.2) shows the relationship between lamp life and the switching cycle of fluorescent lamps used with conventional control gear (CCG). It can clearly be seen that switching cycles of less than 3 hours will result in a dramatically reduced lamp life; however, by extending the switching cycle, lamp life will also be extended.

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Lifetime [%]

Triphosphor 24 20155 3 0

20

40

60

80

100

120

140

5 min

45 min

3 h

1 h

3hrs-switching cycle (165 mins. ON/15 mins. OFF) Average lifetime: 13,000 hours 230 V/ 60Hz

Switching cycle [h]

Figure 2.2 Relation Between Switching Cycle and Lifetime (CCG)

(c) Luminous Flux and Ambient Temperature. Ambient temperature refers to the temperature immediately surrounding the lamp, not the actual room temperature, and has a major influence on the behavior of a fluorescent lamp. The most efficient mercury vapor pressure of 0.8 Pa occurs when the lowest wall temperature (that is, the cold spot), is between 40-50oC. This corresponds to an ambient temperature of 20-25oC in the case of T8 and T12 lamps and between 33oC to 37oC in the case of T5 lamps. As the bulb wall temperature will change with a change in ambient temperature, the lamp voltage and lamp

28


current will also change. As the product of both these components will be low for both higher and lower than optimum temperatures, the luminous flux produced by the lamp will also be low. Figure 2.3 shows the relative luminous flux/ambient temperature of a fluorescent lamp.

110

100

90

80

70

60 10 20 30 40 50

25°C 35°C

Ambient temperature Tu [°C]

Φ rel. [%]

The optimum luminous flux at 35°C for T5 (∅ 16 mm) can only be achieved with “cut off” technology.

“Cut off” technology (T5)

Conventional ECG (T8)

Figure 2.3 Relative Luminous Flux/Ambient Temperature

These characteristics of fluorescent lamps must be taken into consideration when luminaires are selected. In case of low ambient temperatures such as cool-rooms, for example, a carefully chosen luminaire can act as an insulator to an unfavorable ambient environment. In such a case, a lamp will need a warming-up period before it reaches maximum output. If, in this example, an open fixture was used, the lamp may not exceed 20 – 25% of its rated output. This shows that, in order to obtain the best possible result, correct heat balance of the lamp is of utmost importance.

Low temperature can also affect the starting behavior of fluorescent lamps.

29


The location of the cold spot (Figure 2.4) varies for different types

of lamps. For most linear fluorescent lamps, the cold spot is located half way along the glass tube, while for T5 linear fluorescent lamps the cold spot is at the same end as the lamp ‘stamp’. With most compact fluorescent lamps, the cold spot is at the bend of the glass tube; however, the cold spot in amalgam lamps is located in the lamp base.

Cold spot

Linear Fluorescent lamp - Cold

Cold spot

Compact Fluorescent lamp - Cold

T5 Linear Fluorescent lamp - Cold

Cold spot Lamp ‘stamp’

Figure 2.4 Cold Spots

(d) Energy Efficiency. The ratio of transformation of electrical energy into “visible energy” is an important indication as to the efficiency of a light source. It is this measure that greatly influences the choice of a light source and fluorescent lamps compare extremely favorably with other lamps.

To determine the effectiveness one must first consider the energy

loss of the conversion of UV radiation into visible radiation. This jump in wavelengths from 254nm (the most powerful UV radiation line) into the 550nm region represents an energy loss of around 50%. Assuming efficiencies of 80% for the mercury emission, 75% for the fluorescent coating and the losses in the electrodes, an overall efficiency of around

30


25% results. This is still 3 to 4 times greater than the energy transformation rate of an incandescent lamp.

2.2—LINEAR/TUBULAR FLUORESCENT LAMPS The commonly used old type 1.2-meter length 40-watt fluorescent (F40T12) lamp is filled with argon gas. It uses halophosphor “daylight” for its phosphor coating. The newer 36W T8 fluorescent lamp has basically the same construction (although of smaller diameter) and is filled with argon or a mixture of argon and krypton. Unlike the older lamps, T8 phosphor coating can either be halophosphor or triphosphor. The newest T5 lamps only use the triphosphor coatings. Figure 2.5 illustrates the nomenclatures used to specify fluorescent lamps. The F40T12 is still the most common light source in the Philippines even though there are now more energy efficient fluorescent lamps in the market, such as the F36T8 lamps. The number following the “T” represents the diameter of the tube in 1/8 of an inch increment.

31


Figure 2.5 Fluorescent Lamp Nomenclature [Illuminating Engineering Society (IES) Nomenclature]

[International Electrotechnical Commission (IEC) Nomenclature]

32


Table 2.1 Color of Light and Color Rendering Properties of Fluorescents

Color of Light Color

Rendering

Index (Ra) Daylight

above 5000 K Cool White 4000 K

Warm White below 3300 K

Group 1 Very good

1A Ra90-100

1B Ra80-89

950 Daylight 5400 K

965 Daylight 6500 K

860 Daylight 6000 K

940 Cool White 3800K

840 Cool White 4000K

930 Warm White 3000 K



Group 2 Good

2A Ra70-79 2B Ra60-69

Daylight 6000 K

Universal White 4000 K Cool White 4000 K

Group 3 Acceptable

Ra40-59

Warm White 3000 K

International Type Designations The international color code: The first digit stands for the color-rendering group:

9 = color rendering group 1A (Ra90-100) 8 = color rendering group 1B (Ra80-89) 7 = color rendering group 2A (Ra70-79) 6 = color rendering group 2B (Ra60-69) 5 = color rendering group 3 (Ra50-59) 4 = color rendering group 3 (Ra40-49)

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When connected with conventional electromagnetic ballasts, most lamps deliver less than 100% of their rated lumens. The percentage of actual lumens generated is known as the ballast factor, an important figure to consider when making lighting calculations. The ballast factor is the ratio of the light produced by a particular lamp ballast system to the rated light output of the same lamp(s) on ANSI reference ballast operated in free air at 25oC. The term "ballast factor" implies that it is a property of the ballast, but it is really a property of the lamp-ballast system. For instance, the ballast factor for a given ballast will be different depending on whether it is operating a F40T12 lamp or a F40T12/ES lamp. See Chapter 5 Energy-Efficient Fluorescent Ballasts for more information on the ballast factor. 2.2.1 Technical Advantages of Triphosphor Lamps

(a) Lower Depreciation of Luminous Flux. The fluorescent

coating is subject to natural ageing during a life of a lamp, with the result that the luminous flux decreases. This disadvantage has been minimized by the use of a special phosphor coating, which results in 90% of the original luminous flux being maintained even after 12,000 or more hours of operation.

(b) High Luminosity. The special triphosphor materials used

guarantee a high luminous flux with a high luminous efficiency of up to 96 lm/w.

(c) Large Selection of Light Colors and Optimum Color

Rendering. The triphosphor lamp is available in every light color for all the various requirements to be met by a modern lighting system in commercial and industrial use: the right light color for every lighting application – with color-rendering level 1B (excellent – Ra 80-89).

(d) More Environmentally Friendly. Mercury is essential for

ensuring the functionability and luminaire efficiency of the lamp. Triphosphor contains mercury, but no more than is necessary to guarantee reliable operation, even when used in outdoor applications.

All the materials used for the triphosphor, from the glass to the

phosphor coating and packaging, can be recycled and reused. In addition,

34


the high luminous efficiency and long service life as compared with the more common halophosphor lamps ensure that fewer lamps are required and extend the intervals between servicing. In summary: lower power consumption to generate more light, fewer lamps to produce the same brightness and 100% recyclability. 2.2.2 Advantages of Replacing Halophosphor Fluorescent Lamps with Triphosphor Lamps in Existing Systems. The triphosphor fluorescent lamps can be used to modernize existing systems with halophosphor lamps without necessitating any technical changes whatsoever and considerably improve the performance of these systems at the same time.

(a) Improved Economical Operation. Use of the triphosphor

lamps instead of halophosphor fluorescent lamps tangibly increases the luminous efficiency obtained with the same installed power.

Table 2.2 Comparison of Halophosphor and Triphosphor Lamps

Halophosphor Fluorescent Lamps 6500 K–Conventional Control Gear (CCG)

Wattage (W) 18 36 58 Luminous flux (lm) 1,100 2,600 4,000 Luminous efficiency (lm/W) 61 72 71

Triphosphor 6500 K-Conventional Control Gear (CCG) Wattage (W) 18 36 58 Luminous flux (lm) 1,350 3,350 5,200 Luminous efficiency (lm/W) 75 93 90

LUMINOUS EFFICIENCY +23% +30% +27%

The higher luminous efficiency of the triphosphor lamp guarantees up to 30% more light with the same number of lamps and the same installed power.

35


Halophosphor Fluorecent Lamps

Triphosphor

Figure 2.6 Lumen Maintenance

(b) Longer Service Life. The decline in the luminous flux of the triphosphor is tangibly lower than in conventional halophosphor fluorescent lamps. After 12000 hours of operation or more, the remaining luminous flux is still equal to 90% of the original value, as compared with only about 70% in a halophosphor fluorescent lamp.

Use of the triphosphor lamps guarantee:

(1) A constant average lighting intensity very close to the nominal lighting intensity of the system and in conformity with the relevant standards. That is a major advantage and also improves general safety: just imagine the risks associated with a roughly 30% drop in the lighting level when working with such machinery as lathes, milling and drilling machines, etc.

(2) Long intervals and less maintenance to maintain the average lighting intensity at the required level.

36


(c) Large Selection of Light Colors. The range of triphosphor lamps includes the ideal light color for every application, as the variety of light colors available is larger and more comprehensive than in the case of halophosphor fluorescent lamps.

(d) Better Color Rendition. Due to the special coating of the

triphosphor, the color rendering is improved from a level of 2A to 2B – good – for conventional halophosphor fluorescent lamps to 1B – excellent. In other words, the color rendering of illuminated objects is improved distinctly and that is a matter of great importance for instance in the textile industry, the graphics sector, at exhibitions, in sales and showrooms, and in private homes. 2.2.3 The Right Light Color for Every Application

(a) Choice of Light Color. Choosing the right light color is first and foremost a matter of personal taste, although it also depends on local customs, the mood and the manner in which a person perceives the light.

This table contains basic information for planning and tendering, so

that you can choose the right light color for every application.

Table 2.3 Appropriate Color Choices by Application

Application

Daylight/ Cool

Daylight

Cool White

830 Warm White

827 Warm White

OFFICES Offices, corridors ° ° ° Conference rooms ° ° ° INDUSTRY AND TRADE Electrical engineering ° Textile industry ° ° Graphics sector, laboratories ° ° Wood processing ° ° Storage rooms, haulers ° SCHOOLS & LECTURE HALLS Kindergartens ° ° ° Libraries, reading rooms ° ° °

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Table 2.3 (continued)

Application

Daylight/ Cool

Daylight

Cool White

830 Warm White

827 Warm White

SOCIAL AMENITIES Restaurant, inns, hotels ° ° Theaters, concert halls, lobbies ° PUBLIC AREAS Sports facilities ° Art galleries, museums ° ° ° BUSINESS OUTLETS Food trade ° ° ° Bakeries ° ° Deep-freezers and freezer cabinets ° Cheese, fruit and vegetables ° Fish ° Textiles, leather ° ° Furniture, carpets ° Sports equipment, toys, stationery ° Photographic supplies, clocks, watches, jewelry

° °

Cosmetics, hairdressing ° Flowers ° ° Department stores, supermarkets ° ° ° HOSPITALS Diagnosis and therapy ° Examination rooms, waiting rooms ° ° RESIDENTIAL SECTOR Living rooms ° Kitchens, bathrooms, hobby rooms, basement areas

° °

(b) Cultural Influences. A warmer color of light is preferred in northern countries, while cooler light is more frequently favored in the south. This is essentially due to the fact that people who are regularly exposed to strong sunlight tend to prefer an artificial light that is perceived as being “cool” and vice versa.

Lamps emitting a warm light will almost certainly be preferred in homes furnished with a great deal of wood, while white furniture, marble

38


and chromium look better in white light or a daylight color. Warm light conveys a sense of rest and relaxation, while white light and daylight colors are associated with concentration and a positive working atmosphere.

2.2.4 Color Temperature

(a) Daylight Color. Fluorescent lamps in color 860 are ideal sources of light in all rooms requiring artificial light of daylight quality. Rooms in which minor differences in color shades must be clearly recognizable and in which the colors must be reproduced as naturally as possible. This is important, for example, in retail outlets, selling garments, photographic supplies and optical equipment, jewelry or flowers, as well as in the textile industry, doctors’ surgeries, print shops, newspaper offices and the graphics sector.

(b) Cool White Color. With a color temperature of 4000 K, the

triphosphor cool white light is roughly halfway between the light color resembling daylight and the light of incandescent lamps. It is therefore ideal for use at workplaces, particularly in industry, commerce and trade, in offices at exhibitions and trade fairs, as well as sports events. The lamps can also be used for various purposes in the home, for instance in corridors, kitchens, bathrooms, basement areas and workshops and gyms.

(c) 830 Warm White Color. Triphosphor warm white is the ideal

light color whenever a bright, yet comfortable light is required. This light is perceived as being pleasantly “warm” on account of its color temperature of 3000 K. It creates a pleasant atmosphere in which to feel comfortable.

Triphosphor warm white lamps are used wherever a bright basic

light and a positive mood are required, such as in salesrooms, exhibition rooms, trade fair halls, schools, lecture halls, kindergartens, offices and conference rooms.

(d) 827 Warm White Color. Of all the triphosphor lamps, this

color version comes closest to the warm light of an incandescent lamp. With a color temperature of 2700 K, it gives its surroundings a feeling of homeliness and comfort. Wood, for instance, is highlighted particularly

39


strongly by this light color; this makes it ideal for use inside furniture and for indirect lighting. All residential rooms, conference rooms, lecture halls, libraries, hospital rooms and waiting rooms are other major areas of use for this light color. Triphosphor 827 warm white creates an extremely pleasant light in hotels, public halls, foyers, inns and restaurants, theaters and concert halls and creates a relaxing atmosphere in libraries, lecture halls and conference rooms. 2.2.5 Environmentally Friendly. There is a machine known as the “cut-and-separate machine” which selectively separates the various components contained in waste lamps and prepares these for reuse in the manufacture of new lamps. Ninety-three percent (93%) of the components removed in this way can be reused to produce new fluorescent lamps. The remaining 7% are recycled and processed into materials with a whole range of possible uses: for sandblasting, as additives for the cement industry, or mixed with foamed glass for the manufacture of bricks, prefab elements, pipes and material for the building industry. 2.2.6 Lower Mercury Content. With fluorescent lamps being discharge lamps, the use of the mercury in the filling gas is indispensable, for it is impossible to generate light without igniting the mercury. To this day, it is still not possible to completely eliminate the mercury content. 2.2.7 Recyclable Packaging Materials. The lamp packaging also constitutes a waste volume, the importance of which must not be underestimated for the environment. In addition to the individually packed versions, there is also simple industrial packaging, which makes it much easier for bulk customers to change lamps and reduce the volume of packaging waste by up to 45%. 2.2.8 Recent Products

(a) T8 Lamps. Two other fluorescent lamp types have significantly improved efficacy, when compared with the conventional F40T12 lamp-ballast system. These are the 36-watt (Asia) and 32-watt (US) T8 lamp

40


varieties, which uses the common medium bipin base. T8 28W lamps have also been introduced (US Standard) as an alternative to T8 32W lamps. These are compatible with existing 32W electronic control gear and offer lower consumption versus the 32W system but have a slightly lower luminous flux. Smaller lamp diameters and the exclusive use of rare earth phosphors increase the efficacy of these lamps over conventional F40T12 lamps. In addition specially designed ballasts may be used for even greater increases in lamp-ballast system efficacy.

The linear T8 lamps have the same medium bi-pin bases as T12

lamps, allowing them to fit the same sockets (this is not true for the U-bent T8 lamps, which have different leg spacing than their T12 counter parts). However, T8 lamps have different electrical characteristics, so they may not use a conventional F40T12-type lamp ballast designed for 430-milliampere operation.

Like conventional F40T12 lamps, the T8 lamps are rated at 8000

hours for 60 Hz operations. However, for highest efficacy, they are often matched with an electronic ballast that operates the lamps in an instant start mode and at 25 kHz (electronic ballasts for rapid start operation are also available). Instant start operation of T8 lamps reduces rated lamp life by 25% (based on 3 hours per start operation), but lamp efficacy is increased by more than 10% when compared with magnetically ballasted operation. In most commercial applications, where lamps are on for a period of 10 hours between starts, lamp life is only slightly less than that of rapid start operation. Like T12 1amps, T8 1amps may be dimmed, but they require specialized dimmers and ballasts to work properly.

Table 2.4 shows the comparison between several T8 lamp-ballast

systems as against T12 lamp-ballast systems.

41


Table 2.4 Linear Fluorescent Lamp Comparison (32/36/40W)

No.

Parameters

28W (Triphosphor)

Fluorescent Lamp

32W (Triphosphor)

Fluorescent Lamp

32W (Standard) Fluorescent

Lamp

36W (Triphosphor)

Fluorescent Lamp


Lamp


Lamp 1 Rating 28W 32W 32W 36W 36W 40W 2 Length 1200 mm 1200 mm 1200 mm 1200 mm 1200 mm 1200 mm 3 Lamp Base G 13 G13 G13 G13 G13 G13 4 Diameter T8

(26mm) T8 (26mm)

T8 (26mm)

T8 (26mm)

T8 (26mm)

T12 (38mm)

5 Color Temperature

Cool White Daylight/ Cool white Warm white

Daylight Daylight/ Cool white Warm white

Daylight Daylight

6 Life Time Average

26000 hrs (w/ electronic ballast)

20000 hrs (w/ electronic

ballast)

20000 hrs (w/ elec. Ballast)

20000 hrs (w/ electronic

ballast)

8000 hrs 8000 hrs

7 Color Rendering Index

85 82 75 80-89 60-69 60-69

8 Luminous Flux

2725 lm 2950 lm 2700 3250 lm 2600 lm 2500 lm

9 Luminous Efficiency

97.32 Lumens/ watt

92.18 Lumens/ watt

84.38 Lumens/ watt

90.27 Lumens/ watt

72.22 Lumens/ watt

62.50 Lumens/ watt

• Typically the two-lamp F32/36T8 system with an energy-efficient

magnetic ballast has an efficacy of around 15% higher, as compared to a standard two-lamp F40T12 lamp system.

• Even a higher efficacy can be achieved when using electronic

ballast. For example a two-lamp F32/36T8 system with an instant start electronic ballast can achieve a 15% higher efficacy than for an electronically ballasted two-lamp F40T12.

• Some T8 lamps contain rare earth phosphors. RE phosphor

coatings (triphosphor) give T8 lamps improved color rendering and lamp lumen maintenance over T12 halophosphor lamps.

42


• Standard T8 (halophoshpor) lamps are now cheaper than halophosphor T12 lamps. Overall, on a lifecycle cost basis, T8 lamp-ballast systems are always a better investment than any T12 system. As such, T12 lamps mostly remain on the market for replacement purposes, where the ballast cannot start a T8 lamp. T12 lamp/ballast combinations should never be used for retrofitting lamp and ballast systems nor for any new installations. 2.2.9 New Developments and Trends

(a) T5 Linear Lamp Technology. T5 technology has really evolved

as a lighting system rather than just an isolated lamp development. The T5 system consists of a 16mm double-ended tubular fluorescent lamp, optimized for use with an electronic ballast, which operates the lamp at high frequency (ECG), to enhance its efficiency.

One significant change introduced with this system is that the lamp

length and wattages are different to those available with either T8 or T12 fluorescent lamps. T5 lamps are 16mm in diameter, or 5/8 of an inch, which is why they are commonly referred to as ‘T5’. These lamps are available in lengths, which are approximately 50mm shorter than the most commonly used T8 lamps (26mm diameter) lamps.

(b) Applications. Some of the best reasons for using T5 lamps

include: (1) T5 lamps are more environmentally friendly than T8 or T12

lamps, they have:

a. Reduced glass b. Reduced gases c. Reduced phosphor d. Reduced Mercury

(2) Luminaire costs will benefit from the compact size of T5

lamps, with reductions in the costs of material, freight etc. (3) Higher luminous output (at a realistic temperature) can mean

fewer luminaires will be required

43


(4) Compact size allows for shallower luminaires, having a big impact on lighting design in areas with limited ceiling space and for suspended systems.

(5) The system as a whole, will contribute to energy savings. (6) Luminaires designed around T5 lamps and ECGs can be

more aesthetically pleasing, while at the same time, contributing significantly to the quality of the lighting.

With T5 lamps being shorter and slimmer than T8, one other

advantage is that there should not be any ‘mix-ups’, by contractors or maintenance personnel, once ongoing maintenance gets underway. For example, a T5 lamp cannot be installed in a luminaire designed for T8 lamps and vice versa.

Another advantage associated with the reduced length of T5 lamps is

the overall length of luminaires. With the most common size of ceiling grids being 1200mm x 600mm, it is impossible to have a continuous run of more than two luminaires when using T8 lamps, since the length of a 36W lamp alone is 1200mm. The T5 range includes two lamps that have a length of 1149mm—the FH 28W and the FQ 39W. This length of 1149mm, once the additional length of the lamp holders and metal ware is added, still allows the luminaires to fit neatly between the ceiling supports. 2.2.10 Efficient Operation of T5 Lamps - With ECGs. Electronic control gear, like the previously used magnetic ballast is firstly required to regulate the operating conditions of the lamp. However, it can achieve greater efficiency by incorporating high frequency operation and other circuitry refinements such as “cut off” technology, which eliminates filament losses, sensing concepts that react to adverse conditions to protect the lamp and electronic ballast (ECG) together, contribute considerably to prolonged lamp life. Most importantly, an electronic ballast by design minimizes losses within itself, contributing to overall efficiency of the system. They consume only 2 or 3-watts per lamp.

44


Incorporated into the ECG is a ‘soft start’ facility and power factor correction, eliminating two components that often contribute to the maintenance costs. 2.2.11 Burning Positions. When T5 lamps are installed in vertical burning positions, care must be taken to ensure the ‘stamp’ or marker is at the bottom. If two or more T5 lamps are installed very close together, it is best to ensure that the stamped ends are next to one another. Likewise, T5 circular (FC) lamps should be installed in a vertical burning position, for example, in wall-mounted installations, the base must be at the bottom (cap end) as shown in Figure 2.7 below.

Figure 2.7 T5 Circular (FC) Lamp Burning Position

2.2.12 Standard for Linear Fluorescent Lamps. Philippine National Standards (PNS) require the display of an energy label for all linear fluorescent lamps. This will allow the buying public to compare power input, light output, and efficacy (lumens per watt). Manufacturers, suppliers and importers are required to label every individual lamp with the above parameters. Figure 2.8 shows a sample of the newly required energy label for Linear Fluorescent Lamps by the Department of Trade and Industry-Bureau of Product Standards.

45


O512

-345

678 Brand Name :

Model/Type : Light output, lumens : Wattage rating, watts : * based on standard test conditions

Important : For lamps with same wattage rating, HIGHER EFFICACY means MORE ENERGY SAVINGS THE MINIMUM EFFICACY SET BY THE GOVERNMENT FOR THIS TYPE OF LAMP IS 70 lumens per watt.

lumens/watt

EFFICACY*

O512

-345

678

DEPARTMENT OF E N E R G Y

P H I L I P P I N E S

Figure 2.8 Energy Label for Linear Fluorescent Lamps

2.3—COMPACT FLUORESCENT LAMPS The continuing rise in the popularity of compact fluorescent lamp technology is good evidence of its value as an energy-efficient, long-lasting substitute for the incandescent lamp. The average compact fluorescent lamp consumes only one-quarter to one-third as much energy as its incandescent counterpart and will last up to ten times longer. For example, a 10000-hour, 13-watt compact fluorescent lamp (about 17 watts with a magnetic ballast) will provide about the same illumination as a 60-watt incandescent lamp that has a life of approximately 1000 hours. Compact fluorescent lamps are available in a wide range of color temperatures, from 2700 K to 6500 K. They have very good color rendering properties, and they are available in a variety of sizes, shapes, and wattages. The increasing availability of luminaires designed for compact fluorescent lamps in both new and remodel applications means that compact fluorescent lamps can meet most any design application requirement. Compact fluorescent lamps were developed in the late 1970’s and introduced in the Philippine market in the 1990’s. Early model lamp production concentrated primarily on the retrofit market. Integral lamp-ballast combinations with screw-in Edison bases provided a convenient and inexpensive alternative to traditional incandescent lamps for hotels, apartment complexes, and other high-volume user. Modular systems with replaceable lamps were popular, as well. Relatively recent large-scale

46


production of dedicated compact fluorescent luminaires has extended the range of applications for this technology. 2.3.1 Technology Description. Compact fluorescent lamps are actually lighting systems consisting of a lamp (often with a starter integrated into the base), a lamp holder, and ballast. Sometimes, a screw-in socket adapter is incorporated into the package. It is based on the principle of the fluorescent tube in which a phosphor coating transforms some of the ultraviolet energy generated by the discharge into light. Generally, there are three different types of compact fluorescent lamp-ballast systems:

• Integral systems are self-ballasted packages and are made up of a

one piece, disposable socket-adapter-ballast, and lamp combination.

• Modular systems are also self-ballasted packages, consisting of a screw-based incandescent socket adapter-ballast-lamp holder, and replaceable lamp.

• Dedicated systems exist when a ballast and fluorescent lamp socket have been directly wired in as a part of the luminaire. While integral and modular systems are designed to screw into existing incandescent medium base sockets, dedicated systems generally are OEM (Original Equipment Manufacturer) components, supplied with luminaires.

Lamps are easily replaceable in both modular and dedicated compact fluorescent systems. On the other hand, relamping in an integral system requires the replacement of the entire integral unit. Modular and integral compact fluorescent systems leave particular relevance in retrofit applications. Dedicated systems are designed primarily for new construction and complete remodel purposes, although several companies have introduced dedicated hardwire retrofit kits for downlights recently. Simple permanent conversion kits for exit signs and table lamps are also available.

(a) Lamp Types. The following lamp types are commonly available

from a number of manufacturers:

47


(1) T4 diameter twin-tube two-pin lamps that have a starter built into the lamp plug base. They operate on inexpensive reactor magnetic ballasts, come in wattages from 5 to 13 watts and are available for both modular and dedicated systems.

(2) T4 and T5 diameter quad-tube two-pin lamps that also have plug bases and built-in starters. These lamps produce more light than simple twin-tubes and are available up to 27 watts. These lamps are available for all compact fluorescent systems.

(3) Both T4 and T5 diameter twin-tube and quad-lamps are now available in four-pin versions that do not contain a starter in the base of the lamp. These lamps are designed primarily for use with electronic ballasts.

Compact fluorescent lamps for self-contained integral systems are

generally a twin or quad-tube integrated with ballast and a screw-in socket base. In some cases a reflector or surrounding diffuser may be included in the package as shown in Figure 2.9 below.

Figure 2.9 Compact Fluorescent Lamp-Ballast Systems (b) Amalgam Lamps. Amalgams are mercury compounds, which

allow the lamp to operate with a lesser degree of influence caused by operating temperatures. The luminous flux vs. temperature curve is spread out i.e.: the luminous flux will be at least 90% over a large temperature range, from 5oC to 65oC, as shown in Figure 2.10.

The cold-spot in amalgam compact fluorescent lamps is within the

base, rather than at the bend in the glass tube, as it is for standard CFLs.

48


Figure 2.10 Typical Luminous Flux/Temperature Curves for 18W Amalgam CFL

(c) Lamp Life-Lumen Depreciation and Mortality. Similar to

tubular fluorescent lamps, average life depends on the type of control gear as well as switching cycle and ambient temperature. Typically a high-grade compact fluorescent lamp would last about 8000 hours on Conventional Control Gear (CCG) and 10000 hours on Electronic Control Gear (ECG).

(d) Ballasts. Compact fluorescent lamps are discharge lamps

requiring ballasts to start and operate properly. A ballast provides the necessary voltage to start the lamp and, once started, keeps the lamp in

49


operation. Ballasts also consume energy that must be accounted for when determining the efficacy of a particular lighting system.

Integral and modular compact fluorescent systems combine an

Edison screw base with ballast for direct retrofitting of incandescent luminaires. All other compact fluorescent lamps are designed to have an external ballast that must be specified for each individual lamp type and wattage. Ballast options for compact fluorescent lamps are listed below.

(1) Normal Power Factor (NPF) Reactor Ballasts. NPF

ballasts are common for the smaller two-pin lamp sizes. These ballasts exhibit very low power factors (0.5 for 230 volt), so it is important for engineers to calculate circuit loading carefully when designing the electrical distribution system.

(2) High Power Factor (HPF) Reactor Ballasts. Also for the

smaller preheat lamps, these ballasts contain capacitors to raise the power factor to 0.90. They are more expensive and larger than the NPF type, but they allow for conventional branch, circuit design and lower installation costs.

(3) Conventional Electromagnetic Energy-Saving Ballasts.

The higher-wattage lamps, designed for 2G11-based four-pin operation, generally operate on single or multiple lamp ballasts similar to those used for conventional fluorescent lamps.

(4) Dimming Ballasts. The starterless four-pin lamps can be

used with either a magnetic dimming ballast with appropriate wall box dimmer, or a special electronic dimmer and electronic dimming ballast. Dimming capability of the lamp should be checked with the manufacturer/supplier.

Dimming can only be done with electronic control gear in

conjunction with a dimming system. (5) Electronic Ballasts. Most integral products are now

available that combine a twin, quad, or 6-tube lamp with an electronic ballast. These products eliminate the objectionable starting flicker that has been associated with compact fluorescent lamps in the past.

50


In addition to electronically ballasted integral products, several

manufacturers now offer compact fluorescent luminaires with electronic ballasts instead of standard magnetic ballasts. Electronic ballasts for compact fluorescent lamps offer several advantages over conventional electromagnetic ballasts:

a. The system efficacy (lumens per watt, including ballast

losses) is generally about 20% higher with an electronic ballast. Under test conditions of 25oC, the efficacy of an electronically ballasted compact fluorescent lamp ranges from 50-70 lumens/watt, compared to 40-55 lumens/watt for a magnetically ballasted compact fluorescent lamp.

b. The starting time of electronically ballasted lamps is generally less than one second, while magnetically ballasted lamps typically require one to four seconds to start.

c. Electronic ballasts reduce lamp flicker. d. Electronic ballasts operate without any perceptible noise. e. Electronic ballasts can be manufactured in much smaller

sizes and are lighter than conventional magnetic ballasts.

A disadvantage of electronic ballasts for compact fluorescent lamps is their higher price. This is compounded by the fact that there are few electronically ballasted modular type compact fluorescent systems where the lamp can be replaced separately from the electronic ballast; integral electronic designs require that the ballast be disposed of with the lamp. In addition, many of the current products exhibit a high percentage of total harmonic distortion (THD). The effects of THD produced by compact fluorescent lamp ballasts are still being evaluated by utilities, but it appears that the actual harmonic current is insufficient to cause major concern.

(e) Power Quality Issues. Low power factor is one indicator of the effect that compact fluorescent lamps can have on the power quality of a utility distribution system. Compact fluorescent systems generally have power factors much lower than the 90% level achieved for high quality ballasts in typical linear fluorescent lighting systems. Power factor is a performance measure that determines how effectively input current is converted into actual usable power delivered to the lamp. Optimum

51


power utilization would result in a power factor of 1.0, meaning that the product of voltage and the current (volt-amperes or VA) is equal to the power used. Most compact fluorescent lamp systems, regardless of whether they are magnetically or electronically ballasted, are supplied with NPF ballasts, rated between 0.50 and 0.70 at 230 volts. Thus, a 13-watt lamp drawing a total load with ballast of 17 watts at a power factor of 0.50 actually draws 34 VA at 230 volts-twice as much current as it would with a power factor of 1.0. Branch circuit current and over current protection are based on VA. This makes it important to consult with a utility representative or professional engineer when using large numbers of NPF ballasted compact fluorescent luminaires in a single facility.

High power factor ballasts for compact fluorescent lamps are available. Whether using HPF or NPF ballasts, building engineers should follow the input current instructions of each ballast when designing the circuit loading,

Harmonic distortion is another indicator of the effect of compact fluorescent lamps on power quality. Any nonlinear load, such as a personal computer, variable speed motor, television, or compact fluorescent lamp, causes harmonic distortion in power distribution systems. Most magnetically ballasted CFL lamps have a THD between 15% and 25%. The THD from most available electronically ballasted compact fluorescent lamps may be significantly higher, due to severe distortion of the current waveform. Distortion of the sinusoidal waveform may also be associated with a reduced power factor. A second potential concern is the presence of third (180Hz) harmonics. In principle, these harmonics may cause overheating on the neutral line of three-phase systems in older commercial buildings. This generally is not a practical problem for compact fluorescent lamps, because of the relatively small size of the load imposed by these lamps.

There are products currently available that reduce both the THD and the odd harmonics from electronically ballasted lamps to levels approaching those of magnetic ballasts. Electronically ballasted integral lamp-ballast packages with high power factors and low THD are currently available in the market. However, increased size requirements, increased radio frequency interference (RFI), and cost factors have slowed the development of similar products.

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(f) Dimming. In general, compact fluorescent lamps cannot be dimmed using conventional dimming equipment. For example, according to at least one lamp manufacturer, using conventional incandescent dimmers in an attempt to dim integral units especially those using electronic ballasts can cause a fire. However, there are two specific products that enable dimming of compact fluorescent lamps:

(1) Dimming adapters permit an incandescent dimmer to dim a

four-pin quad-tube lamp. The adapter must be used with a specific ballast that is factory-installed on the luminaire.

(2) Solid state dimming ballasts permit the dimming of four-

pin twin-tube and quad-tube lamps with a remote potentiometer or low-voltage signal.

(g) Switching. The longevity of any fluorescent lamp including

compact fluorescents, is affected by the number of times the lamp is switched on and off during its life. Fluorescent lamp life ratings listed in lamp manufacturers' catalogs are based on a specific switching cycle of 3 hours on per start. Fluorescent lamp life may be less than the rated value if the lamp is switched more frequently than this. However, with electronic ballasting technology, manufacturers can include circuitry that optimizes the starting sequence (so-called "soft-starting"), thus preserving manufacturers' rated lamp life even if the lamp is switched more frequently than every 3 hours. The manufacturer should be contacted for more information if the application calls for frequent switching. Of special concern are modern electronic control products. Devices such as illuminated wall switches, wallbox touch switches, wallbox time switches, and wallbox occupant sensors may not be compatible with most compact fluorescent lamps. Incompatibilities are usually caused by the use of solid-state switches (triacs) instead of air gap switches or relays. A small continuous current (insufficient to illuminate an incandescent lamp) passes through the load even when it is "off." In magnetically ballasted compact fluorescent applications, this idling current can cause continuous electrode heater and starter operation, resulting in reduced lamp life. In electronically ballasted applications, the ballast may prevent idle current, in turn rendering the control device inoperable.

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(h) Environmental Conditions and Efficacy. It is important to realize that laboratory environmental conditions under which lumen output ratings are made are often quite different from actual installation conditions. The two environmental conditions that most significantly affect the performance of compact fluorescent lamps are ambient air temperature and the orientation or burning position of the lamp.

Figure 2.11 gives typical performance curves showing how ambient

temperature affects lumen output of compact fluorescent lamps in both base up and base down burning positions. Note that while the compact fluorescent lamp produces rated lumens at 25oC with the lamp base up, its lumen output drops to 80% of its rated lumens at 50oC. In applications where compact fluorescent lamps are mounted in small volume fixtures with a lack of air circulation (such as in lensed downlights), the user should expect that the ambient temperature would be between 40oC and 50oC, and should lower the lamp lumen rating accordingly. Some compact fluorescent luminaire manufacturers provide luminaires designed to improve ventilation in order to lower ambient air temperature and increase lumen output.

Figure 2.11 also shows how lamp orientation (burning position) can

have a major influence on lumen output of a typical compact fluorescent lamp. Under identical ambient temperatures (25oC) a compact fluorescent lamp in a horizontal or base up orientation will produce about 20% more lumens than a lamp in a base down position. As such, in any application where a compact fluorescent is used in a base down position (such as in a retrofit of an incandescent table lamp), the expected lumen output should be lowered by at least 10%. At higher ambient temperatures, a lowering of 15% is appropriate for base down operation. Manufacturers’ data should be consulted for specific values for individual lamp types, as performance differences are related to lamp shape and wattage.

54


NOTE: Curves shown are for one specific lamp type in a draught-free environment. Performance-particularly in the base down position –will vary significantly depending on lamp configuration and wattage. (Source –Osram Corporation)

Figure 2.11 Typical Ambient Temperature and Lamp

Orientation Effects on Lumen Output of Compact Fluorescent Lamps.

2.3.2 Current Products. As stated previously, compact fluorescent lamps are highly efficacious, have very good color rendering capabilities and are available in several color temperatures. Their performance is due to the use of high efficacy, high color rendering rare earth (RE) phosphors. The relative balance among these phosphors determines the color temperature of the lamp. RE phosphors are essential to the operation of the compact fluorescent lamp because of the high power density in the small diameter tube. The same loading of conventional halophosphors would result in rapid and severe lamp lumen depreciation. Most compact fluorescent lamps are capable of generating about 50-60 lumens/watt. Their advantages notwithstanding, compact fluorescent lamps have similar overall efficacy as several other technologies of equal lumen output, such as low-wattage metal halide and high-pressure sodium lamps, and conventional straight, U-shaped, or circular fluorescent lamps.

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A new square-shaped "double-D" configuration is now available in different sizes and wattages. Its compact shape and size make it suitable for low profile surface and small recessed luminaires. A T2 diameter, sub-miniature, wedge base fluorescent lamp is now produced in a wide range of lengths and wattages. It is available in both hot and cold cathode versions. As is true with all compact fluorescents, these lamps use RE phosphor coatings for good color rendering. T2 lamp efficacy is more than 80 lumens/watt, exclusive of ballast losses. Suitable applications for this lamp will probably include task, sign, and showcase lighting. Several manufacturers are now offering compact fluorescent lamps consisting of three bent tubes (as opposed to twin-tube and quad-tube configurations). This allows for more lumens in a smaller package. Some manufacturers have begun producing an electronically ballasted 20-watt compact fluorescent, with high power factor and low THD. This type of lamp produces similar lumens as a 75-watt to 100-watt incandescent lamp.

(a) New Lamp Products. In addition to the familiar types of

compact fluorescent lamps, several new lamp configurations are becoming available.

Current research into new compact fluorescent lamp configurations

is concentrated on more varieties of lamps with higher powers, different shapes, and single-ended, four-pin bases (2G7, 2Gl1, etc.). These lamps can use electronic ballasts, can be dimmed, and will eliminate much of the starting flicker that has been associated with the use of compact fluorescent lamps. This development promises to increase the number of compact fluorescent lamp applications. Recently, high wattage self ballasted and externally ballasted CFL systems in the 70W-120W range have been introduced in the market, as well as decorative self ballasted CFLs with e27 bases in circular, spiral and bulb shapes.

(b) Luminaire Types. Lower wattage compact fluorescent lamps

are designed to be used in place of incandescent lamps in a wide variety of luminaire shapes and types. The twin-tube style is especially good for task lights, wall sconces, exit signs, step lights, and exterior path lighting.

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Two-lamp, horizontally aligned, twin-tube combinations have become an excellent substitute for incandescent recessed downlights, and many manufacturers of recessed luminaires have designed series of luminaires around this concept. The quad-tube lamp has similar applications as a downlight, wall washer, and sconce light. Figure 2.12 illustrates some luminaires that use compact fluorescent sources.

Figure 2.12 Compact Fluorescent Luminaire Application

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(c) Retrofitting. Modular and integral compact fluorescent systems

with Edison screw-in sockets are generally not as efficient as their dedicated counterparts, but they do offer a means to upgrade existing incandescent lighting. Modular and integral lamps are available with either electronic or magnetic ballast. The electronic ballast operates at a higher efficiency and without noise or flicker.

(d) Incandescent Lighting Alternatives. Compact fluorescent

lamps can generally be utilized in many areas where incandescent lamps would typically have been used before. Such areas can include recessed downlights, wall washers, desk lights, and wall sconce-type ambient fixtures, under cabinet fixtures, landscape lights, residential floodlights, and a variety of other applications. In most instances, compact fluorescent lamps produce three to four times more lumens per watt than incandescent lamps as shown in Figure 2.13.

Figure 2.13 Comparison between Incandescent Lamps and CFLs

12 watts, uses less electricity

50 watts, uses more electricity

ENERGY SAVER

=

570 lumens, white or yellowish color

520 lumens, yellow color

EXTRA BRIGHT

=

4,000-8,000 hours, can last up to 2 yrs

750-1,000 hours,

LONG LIFE

=won’t last a year

58


Replacing incandescent lighting with compact fluorescent lighting

offers significant cost savings to the user. Money saved through reduced energy use, fewer lamp replacements, longer lamp life, and related maintenance savings can quickly recoup the initial investment and provide continuing operating cost savings as shown in Table 2.5 below.

Table 2.5 Comparative Light Output, Efficacy and Operating Hours of Incandescent Lamps (IL) and Compact Fluorescent Lamps

(CFLs)*

Type of Lamps

Wattage rating and equivalent average Light output

Efficacy, lumens/watt

Average life, in hours

Compact Fluorescent

Lamp

5 W to

6 W

7 W to

8 W

9 Wto

12 W

13 Wto

14 W

15 W to

18 W

22 W to

23 W

45 W to 57 W

5000 to

8000 Light output,

In lumens 240 to

260

350 to

400

460 to

570

760 to

800

820 to

990

1280 to

1300 - -

Incandescent

Lamp 25 40 50 60 75 100 8 to 13

750 to

1000 Light output,

in lumens 200 390 520 720 890 1300 - -

*Source: Department of Energy – Lighting and Appliance Testing Laboratory

(e) Alternatives to Other Fluorescent Lamps. In the lower wattages, other smaller fluorescent lamp types, such as circling configurations, lack the convenient single-ended plug base, color temperature options, and consistent good color rendition of compact fluorescent lamps. Many typical fluorescent applications for smaller lamps, such as task lights, surface mounted “drum lights," and corridor lights, will be more effective if compact fluorescent lamps are used. Also, the high color rendering quality of the compact lamp is maintained with every lamp replacement.

(f) Limitations. Overall, compact fluorescent lamps are excellent

choices for many residential and commercial lighting situations. The major limiting factor associated with compact fluorescent lamps in retrofit applications has been their size. Compact fluorescent lamp-

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ballast packages have been somewhat larger than incandescent lamps of the same lumen output, meaning that they may not fit properly in luminaires designed for incandescent sources. For example, in recessed downlights, a screw-in compact fluorescent package may protrude below the ceiling line, resulting in an objectionable appearance and creating glare, In addition, the base portion of a compact fluorescent lamp that contains the ballast is larger and of a different shape than the standard incandescent lamp. The luminaire's reflector may therefore not allow enough clearance for the adapter to be screwed into the socket. For these reasons, designers are encouraged to try out a test lamp of the intended configuration prior to attempting an entire retrofit. Lately however, several manufacturers have introduced much smaller-sized CFLs to mitigate many of these size limitations.

Another limitation of compact fluorescent lamps is that they may not

be suitable in very high ceilings (more than 3.6 m), or in certain accent lighting applications requiring a tight beam spread or a point source sparkle. Furthermore, CFLs are not suitable for areas with voltage fluctuations of +/- 20%; as well as, areas with frequent and short duration switching operations. 2.3.3 Application Guidelines. In general, compact fluorescent lamps are best applied in situations where incandescent or other small fluorescent lamps would be considered. They may be used in a wide variety of residential, commercial, retrofitting, and new construction applications.

(a) Residential Applications. In general, the use of compact

fluorescent luminaires is especially appropriate for rooms such as kitchens and bathrooms where high lumen output and good color rendering are desired. Compact fluorescent lamps are also useful in all utility room lighting applications and in enclosed exterior fixtures (if “weatherized”) such as lantern, and path lights. They are useful as ambient light sources in wall sconces. The extended lamp life of compact fluorescents makes them an intelligent design decision in hard-to-reach places. They are also appropriate for task lights, especially those types designed for the configuration of compact fluorescent lamps. A commitment to increased residential use of compact fluorescent lamps could be quite significant, in terms of energy conservation. A savings of 25% to 50% of the lighting electrical energy used by every home could

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be realized if all acceptable fluorescent applications were utilized. Table 2.6 summarizes some of the residential applications suitable for compact fluorescent lamps.

The selection of compact fluorescent lighting equipment for

residential design applications should be made carefully. Newer designs using electronically ballasted compact fluorescent lamps are suitable for many residential applications, since these packages operate silently and start almost immediately without an initial flicker. An added benefit is the lighter weight and smaller size of the electronically ballasted products. When magnetically ballasted systems are used in residential applications, the benefits of energy efficiency and long life are sometimes outweighed by concerns for the acoustic noise of some ballasts, or by a negative reaction to starting flicker. In most residential applications, these conditions are not tolerable. In any case it is advisable to consult with and advise one's client about the overall benefits of compact fluorescent lighting. Table 2.6 Residential Applications for Compact Fluorescent Lamps

Kitchens Living Rooms

Bedrooms

Bathrooms Utility Area

Exterior

Recessed downlights Under Cabinet lights

Task lights Swing arm lamps Under Cabinet lights Recessed downlights Wall washers

Task lights Closet lights

Mirror lights Recessed downlights Shower & tub lights

Stairways Laundry rooms Attics Closets Crawl spaces

Lanterns Garage lights Path lights Security lights

(b) Commercial Applications. Commercial lighting represents the

best application for compact fluorescent technology. Compact fluorescent luminaires can be easily incorporated into lighting designs

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that are both aesthetically pleasing, and energy-efficient. It is now possible to design a first-class project using compact fluorescents in place of most incandescent lamps.

In office lighting design, not every incandescent luminaire has a

compact fluorescent counterpart, but many do. Offices and other types of commercial and institutional spaces will look good and operate efficiently through the proper use of compact fluorescent troffers, downlights, wall washers, and task lights.

In retail lighting design, fluorescent light is appropriate for general

illumination, wall washing, and some types of case lighting. The energy conscious designer uses standard incandescent or halogen sources only when point source sparkle or significantly more light intensity is required. Examples of this would include display lighting, jewelry case lighting, etc.

In restaurants and hotels, most of the circulation areas and other public spaces can be illuminated with compact fluorescent sources, unless ceilings are especially high, an application where HID sources might be more appropriate. Additionally, some pendant type luminaires and wall sconces can be equipped with compact fluorescent lamps. Incandescent lighting can then be used where it is especially important for full-range dimming and special accents. Many fast food/fast action spaces can take advantage of the smaller general illumination fixtures made possible by compact fluorescent technology. In hospitals, laboratories, schools, and other institutions, compact fluorescent lamps can generally replace most incandescent applications.

In industrial lighting, most compact fluorescent lamps have limited

applications. But the low heat of compact fluorescent lamps makes them safer in hazardous environments where HID lamps might otherwise be used.

Table 2.7 suggests some possible commercial applications for

compact fluorescent lamps.

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Table 2.7 Commercial Applications for Compact Fluorescent Lamps

General Lighting

Accent & Specialty Lighting

Decorative & Portable Lighting

Utility Lighting

Exterior Lighting

Recessed downlights Suspended luminaires Indirect lighting systems

Recessed & track mounted wall washers Under cabinet lights Cove lights Case display lights Modular Strip outlining Sign &display lights

Wall sconces Chandeliers Table & floor lamps Makeup & dressing lights

Security lighting Step lights Exit signs Task lighting

Landscape floodlights Pedestrian post top and bollard lights Step lights Under rail lights Vandal-resistant security lights

(c) General Downlighting. Many corridors and lobbies are

furnished with round or square recessed downlights for general or wall wash lighting purposes. Typical designs call for incandescent “cans" or "tophat" luminaires; an energy-efficient alternative is to use modular type downlights designed specifically for compact fluorescent twin-tube or quad-tube lamps. By careful selection, the specifier can choose a fluorescent luminaire that appears similar to standard incandescent downlights. A general rule-of-thumb is to use about 20% of the required incandescent lamp wattage. In other words, use a downlight with one 26-watt or two 13-watt lamps to replace a 100-watt incandescent lamp; two 18-watt lamps replace a 150-watt incandescent lamp and two 26-watt lamps to replace a 200-watt incandescent lamp. Avoid using screw-in socket adapters in new construction, as they are not as efficient and are easily compromised by incandescent relamping at a later time.

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(d) Outdoor Floodlighting. Compact fluorescent lamp sources have excellent floodlighting capabilities, and there is a significant potential for savings over the use of traditional incandescent sources. Many floodlighting schemes for shorter walls, signs, etc. use an incandescent PAR-38 flood lamp. In many situations, a short fluorescent flood lamp luminaire will serve as an energy-saving option, as long as ambient temperatures are high enough for proper operation. For example, a 22-watt quad-tube compact fluorescent luminaire with reflector would be a good alternative to an incandescent luminaire supplied with a 100-watt PAR-38 lamp. The 22-watt quad-tube luminaire would use 60 watts less (including ballast) than a 90-watt PAR halogen lamp and 70 watts less than a standard 100-watt PAR lamp.

(e) Decorative Lighting. Many pendant lights, wall sconces, and

other types of decorative luminance are available as compact fluorescent lamp sources. Manufacturers of wall sconces in particular have been quick to capitalize on the technology of compact fluorescent lamps, and many products are available. 2.3.4 Cost Savings Retrofit Profile

(a) Residential Retrofit Example. Retrofitting incandescent lamps

with compact fluorescent lamps offers energy savings to consumers. This scenario assumes that an 18-watt CFL replaces a 25-watt incandescent lamp (IL) in order to provide 8,000 hours of operation in the residential sector. It is assumed that the lamps operate 8 hours a day. One (1) CFL costing around PhP 240.00 would displace four (4) IL’s costing a total of P160.00, for a difference of PhP 80.00 (all cost figures are in present value). Over its burning life hours, the CFL would consume 144 kWh costing PhP 1,152.00 at PhP 8.00 per kWh, while IL’s would consume 600 kWh costing PhP 4,800.00, for a difference of PhP 3,648.00. Hence, total savings comes around to PhP 3,568.00 by retrofitting to CFLs as shown in Table 2.8.

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Table 2.8 Costs/Savings Comparison between Incandescent Lamps

and CFL Household X Y

Lamp Type A Incandescent Lamps CFL

Rating per Lamp, Watts B 75 18

Burning hours per lamp C 1 000 8 000

Total burning hours needed for operation

D 8 000 8 000

Number of lamps required E = D/C 8 1

Price per lamp, PhP F 20.00 240.00 Total Price of Lamp, PhP G = E x F 160.00 240.00

Savings on Lamp, PhP 80.00 — Lighting load per lamp, Watts H 75 18

Total electricity consumption, kWh

I = (D x H)/1000 600 144

Average Electricty Cost, PhP/kWh

J 8.00 8.00

Bill per lamp, PhP K = I x J 4 800.00 1 152.00 Savings in Electricity Cost over

the Life of each Quality CFL, PhP — 3 648.00

(b) General Downlighting Example. Energy efficiency with a

compact fluorescent downlight system is significant when compared with incandescent options. For example, to provide 220 lux in a corridor, luminaires are installed about every 3 m2. The fluorescent scheme (two 13 watt twin-tube lamps) operates at about 10.75 watts/m2, while the incandescent scheme (one 100-watt “A” lamp) operates at over 32.25 watts/m2. A saving of over 7.74 kWh/m2/mo. is realized translating into PhP 46.44/m2/mo., or about PhP 139.32/mo./fixture. Added benefits

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result from a much longer lamp life and fewer maintenance costs associated with replacements.

(c) Product Classifications. Lamp manufacturer tend to create

“marketable” product names and identifications. These names make for better marketing, but make it more difficult to write a generic specification. Hence, please refer to manufacturers’ product catalogs in the preparation of CFL specifications. 2.3.5 Standard for Compact Fluorescent Lamps. Philippine National Standards (PNS) require the display of an energy label for all compact fluorescent lamps. This will allow the buying public to compare power input, light output, efficacy (lumens per watt), and average life. Manufacturers, suppliers and importers are required to label every individual lamp with the above parameters. Figure 2.14 shows a sample of the newly required energy label for Compact Fluorescent Lamps by the Department of Trade and Industry-Bureau of Product Standards.

66


Brand Name:

Model/Type:

Lamp Specifications 1

Light Output lumens

Power Consumption watts

Efficacy 3 lumens per watt

Average Life 2 hours

For lamps of similarlight output, higher

efficacy means more energy savings

1 when tested at standard test conditions

2 rated average life at 50% failure

3 The Minimum Efficacy Set By The Government For

This Type Of Lamp Is ___ LUMENS PER WATT.

CTRL NO. XXXX-XXXXXX

DEPARTMENT OF E N E R G Y

P H I L I P P I N E S

Figure 2.14 Energy Label for Compact Fluorescent Lamps

2.4—NEW TECHNOLOGY 2.4.1 Induction (Electrodeless) Lamps. Induction lamps (Figure 2.15) do not have electrodes. In contrast to conventional fluorescent lamps, the discharge needed to generate light in the induction lamp does not take place between two electrodes but through a closed “ring” with no starting

67


point and no end point. The energy is “injected” via ferrite rings from outside the lamp using magnetic fields (induction principle). The frequency generator produces a 2.65 MHz (radio frequency) alternating current and supplies it to the induction coil (a wire wrapped around a plastic or metal core). The current passing through the induction coil generates an electromagnetic (EM) field. The EM field excites the mercury in the gas fill. The ionized mercury emits ultraviolet (UV) radiation, which causes the phosphor coating inside the lamp glass to fluoresce. The advantage of eliminating electrodes is extended lamp life. The main reason why low and high intensity discharge lamps fail is because of the deterioration of the electrodes or filament, which is a result of the reaction of the light-generating substances with metal electrodes in conventional lamps. Since the lamp has no parts that can wear out, it lasts long and may take years before it needs replacement.

Figure 2.15 Induction (Electrodeless) Lamps

The best applications for induction lamps are in street, roadways, tunnels, high bays, parking lot, and area lighting where lamp change-outs are costly or dangerous. Other good applications include overhead machinery, and in production areas where lamp change-outs are disruptive or might decrease production. Advantages:

• Can last up to 30 years, dramatically reducing ongoing operations and maintenance costs,

• Super long life, quick start, no flicker, auto restart, • Deliver higher efficiency (more lumens per watt)

68


• Provide excellent color rendering (CRI over 80) versus HID (CRI: 22 for High Pressure Sodium, and 70 for Metal Halide)

• Energy saving. Saves as much as 60 – 70% without sacrificing illumination level,

• Environment friendly due to very long replacement period.

2.5—GUIDELINE SPECIFICATION

Specifying fluorescent lamps is not difficult. There are ways of ensuring that the preferred lamp and ballast requirements are clear to suppliers to avoid the substitution of inferior products. Furthermore, the designer should specify products that conforms with the following Philippine National Standards:

A. For Linear Fluorescent Lamps • PNS IEC 60081: 2006 (IEC published 2002) Double-capped

fluorescent lamps – Performance requirements • PNS IEC 61195: 2006 (IEC published 1999) Double-capped

fluorescent lamps – Safety requirements • PNS 2050-1-1: 2007 Lamps and related equipment – Energy

efficiency and labeling requirements – Part 1-1: Double-capped fluorescent lamps

B. For Compact Fluorescent Lamps • PNS IEC 969: 2006 (IEC published 1988) Self-ballasted lamps

for general lighting services – Performance requirements • PNS IEC 968: 2006 (IEC published 1988) Self-ballasted lamps

for general lighting services – Safety requirements • PNS 2050-2: 2007 Lamps and related equipment – Energy

efficiency and labeling requirements-Part 2: Self-ballasted lamps for general lighting services

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70

CHAPTER 3. HIGH INTENSITY DISCHARGE LAMPS

71

Chapter 3. High Intensity Discharge (HID) Lamps

INTRODUCTION High-intensity discharge (HID) lamps can offer better efficiency and longer life than fluorescent lamp, with color quality approaching that of incandescent lamp. HID lamps all utilize a compact “arc tube” in which very high temperature and pressure exists. This small arc tube resembles a point source of light, making HID lamps and their luminaires both compact and powerful. There are four main types of HID lamps: mercury vapor (MV), metal halide (MH), low-pressure sodium (LPS), & high- pressure sodium (HPS). Major applications of HID include outdoor floodlighting, roadway lighting, high-bay for industrial environment and sport’s gym. However, due to technology, HID lamps today are also being use in track lighting for offices, commercial and retail environments.

3.1—TECHNOLOGY DESCRIPTION Arc tubes may be made out of quartz needed for HPS lamps. However, because quartz cannot contain the hot and corrosive sodium and vapors, high purity aluminum oxide or “polycrystalline alumina” is being utilized for its high-temperature stability, strength and excellent light transmission characteristics. Recently, arc tubes of this alumina material are also employed in MH lamps, which are described as “ceramics arc tube metal halides”. Ceramic tube can withstand higher temperature and pressures than a conventional glass arc tube. Thus, the lamp has slightly higher efficacy and better color stability.


Figure 3.1 Metal Halide and High Pressure Sodium Lamp Construction

3.2 CURRENT PRODUCTS

As shown in Figure 3.2, HID lamps are available in a wide variety of sizes, shapes, and bases. HID lamp technology development is a continually enveloping process, as manufactures try to design lamp configurations and characteristic to meet an ever widening range of applications. Table 3.1 shows the Color Rendering Index (CRI) and lamp efficacy of the different high intensity discharge lamps as compared with low intensity discharge lamps.

72

CH

APT

ER

3. HIG

H IN

TE

NSIT

Y D

ISCH

AR

GE

LA

MPS

73

Table 3.1 Color Rendering Index and Lamp Efficacy for Typical Light Sources Table 3.1 Color Rendering Index and Lamp Efficacy for Typical Light Sources

Lamp Type Lamp Type Lamp Watts Lamp Watts (CRI)* (CRI)* Initial Lamp

Lumens* Initial Lamp

Lumens* Mean Lamp

Lumens* Mean Lamp

Lumens* Mean Lamp

Efficacy* Mean Lamp

Efficacy* Incandescent 100 100 1 750 1 575 16 Compact Fluorescent 26 82 1 610 1 370 53 Fluorescent (4') Standard Phosphor (T-12/ES)

34

62

2 650

2 300

68

Mercury Vapor Clear Color Improved

250 250

20 45

12 100 13 000

10 500 10 700

42 43

Metal Halide Clear Color Improved Pulse Start

250 250 250

65 70 65

20 500 19 745 26 300

17 000 16 000 21 040

68 64 84

High Pressure Sodium Clear Color Improved

250 250

21 65

28 500 23 000

25 600 20 700

102 83

Low Pressure Sodium 180 0 33 000 33 000 183


NOTE: Not drawn to scale

Figure 3.2 Typical HID Lamps Bases and Envelope Shape

3.2.1 Metal Halide Lamps Metal halide lamp are high-intensity discharge lamp in which the major portion of the light is produced by radiation from a mixture of metallic vapour, metal halides and the products of the dissociation of metal halides. NOTE: The definition covers clear and coated lamps

74


Wattages of metal halide lamps range from 32 to 2000 watts. A large number of envelope and base configurations are available. Major variations of metal halide lamps include:

• Universal-burning-position lamps that are relatively insensitive to

lamp physical orientation • Position-specific lamps that have maximum efficacy and lamp life • Clear or phosphor-coated lamps ranging from 3400-4100K in

chromaticity • Optional warm (3000K) and cool (6500K) lamps in some sizes • A few warm (3000-3200K) clear lamps, especially in lower

wattages • Lamps for open luminaires with internal arc rupture shields (see

section 6.5 for luminaire information) • Silver-bowl lamps that minimize glare and light trespass from

directional luminaries • Compact lamps without outer glass envelopes that produce a

brilliant, high color rendering light in a comparatively small arc tube

(a) Universal-Burning Position. Because of their ability to be

burned in any operating position, the "universal" metal halide lamps are the most easily used. However, they perform best (maximum light output and life) when the arc tube is within about 15 degrees of vertical position. They are also typically less efficacious than lamps optimized for limited burning positions.

Lamp color choice with universal metal halide lamps is generally

limited to standard clear (4000-4500K, 65 CRI) or coated (3700-4000K, 70 CRI). Recent improvements include the addition of more wattage, as well as the development of medium-based compact lamps. These lamps operate on ANSI standard ballasts and generate 65-100 lumens per watt.

(b) Vertical- or Horizontal-burning Position In addition to universal-burning- position products, metal halide

lamps are also available that are designed to operate either vertically or horizontally. When designed for specific burning position, metal halide

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lamps can generate more light and offer more color options than are available with universal-position lamps.


Figure 3.3 Metal Halide Lamp Configurations Vertical Burning. The vertical-burning metal halide lamp is

optimized for base-up, base-down, or base-up/base-down operation, primarily for use in down-lights. In addition to standard clear (4000-4500K) and coated (3700-4000K) lamps, warm color (2700-3200K) clear and coated lamps are available in various wattages. The newest products tend to have lower wattages with medium bases and smaller envelopes. One product—the 32-watt lamp—is designed specifically (and only) for operation on electronic ballast. A principal advantage of vertical-burning lamps is efficacy. Lamps generate 70-110 lumens per watt, or about 10% more than universal-burning lamps. Table 3.2 provides performance information for vertically burning pulse-start metal halide lamps.

Horizontal Burning. As in vertical-burning metal halide lamps,

optimum lamp design in horizontal lamps is achieved when operating position is predetermined. Horizontal high output or "super" lamps may

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have bowed arc .tubes, and use a position-fixing pin in the base, called a prefocus or position-orienting mogul (POM) base. This base and matching socket assure correct positioning of the lamp.

Since these lamps are primarily used in outdoor lighting—

floodlighting and highway signs are two major applications—the smallest wattage product available is 175 watts. The most popular metal halide lamp colors are offered (3200K coated, 3700K coated, and 4100K clear). As with vertical lamps, efficacy is 70-110 lumens per watt.

(c) Color Shift It is characteristic of metal halide lamps to shift in color both

between lamps and over time. As metal halide lamps operate, the circulation of hot gases in the arc tube, the area and position of the "pool" of molten halides, lamp temperature and age all contribute to a continuously changing mixture of halides and their moment-to-moment light and color output. Unfortunately, the most likely lamp color characteristic to change is chromaticity, which is also the most visible to the eye.

There are, however, several strategies that can minimize lamp color

shift so that MH lamps can be used as energy-efficient alternatives to incandescent and fluorescent light sources. Further, lamp manufacturers have struggled with the problem and are beginning to achieve some success, which is apparent with the newer pulse-start and ceramic arc tube products.

There are a number of strategies for minimizing lamp color shift: Specification Considerations

• Determine what color shift is acceptable for the application

and if the acceptability applies to the overall appearance of the lamps over time or the lamp-to-lamp variation at any given time. Recognize that the color stability of metal halide lamps is not expected, at least in the near term, to be the same as that of incandescent and fluorescent lamps.

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• Consult with the lamp manufacturer to determine what variation can be expected and what variation might be put into writing as a warranty of performance.

• Ask lamp and ballast manufacturers about lamp/ballast systems that work together to minimize color shift and variation. Some electronic HID ballast now has sensing and feedback circuitry that helps to stabilize lamp operation.

• Use the same ballast model throughout the installation. • Choose ballasts with good regulation characteristics, especially

if the supply voltage is subject to voltage variations. • Specify newer-technology lamps. Lamps with "shaped" arc

tube chambers; pulse-start technology and ceramic arc tubes are designed to have minimal color shift characteristics.

Installation and Operation Considerations

• Before judging the color of new lamps in an installation, burn

the lamps for at least 100 hours to stabilize the lamp color characteristics.

• If lamps have been moved, and particularly if the lamps have been tipped or shaken when warm, they must be re-stabilized. Operate them for several hours in their new positions.

• Operate all of the lamps in an installation in the same burning position.

• Do not operate metal halide lamps on a dimmer. • If lamp-to-lamp color variation over time is an important issue,

specify group relamping. Lamp manufacturers may select lamps with matching color values on request or at extra cost for critical installations.

• In general, operate lamps with quartz arc tubes vertically. Off-vertical positions are more likely to change the surface area of the halide "pool."

(d) Double-Ended Double-ended metal halide lamps in compact packages (without

enclosing outer glass envelopes), illustrated in Figure 3.4, were originally introduced in Europe and have been very successful there. Some manufacturers produce these lamps with special halide chemistries,

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resulting in lamps with very high CRI of 80 or more. These lamps operate in the range of 35-95 lumens per watt, and the 70-watt lamp with electronic ballast achieves a system efficacy of about 75 lumens per watt, over 10% more than with magnetically ballasted operation. Moreover, the reduced ballast package lends itself to smaller luminaires including track lighting equipment.

Double-ended lamps must be operated with the arc tube within 45

degrees of horizontal.

Figure 3.4 Double –Ended Metal Halide Lamps With FC2 and RSC Bases

(e) Open Luminaire/Protected Lamps Most metal halide lamps require enclosed luminaires to protect

people and property in the event of lamp rupture and, in the case of single-envelope lamps, high levels of UV emissions. Although rare, metal halide arc tubes can fail and burst - especially near its end-of-life, if the lamp has been burned continuously.

However, a few metal halide lamps are listed for use in open

luminaires. These are typically indicated in the "notes" column of

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manufacturers' catalogs. One type is simply a lamp design tested by the manufacturer determined to have a failure risk of virtually zero. Another type is called a protected lamp. These lamps typically employ an inner glass shield or reinforced arc tube so that, in the event of arc tube failure, the pieces are contained within the lamp's outer envelope. Protected lamps have a special base design. If the open luminaire is equipped with the matching exclusionary lamp holder, non-protected lamps cannot be installed.

Of course, the best protection is the use of an enclosed luminaire,

especially if lighting maintenance procedures are such that there is a significant chance that a non-protected lamp could be installed. Protected and non-protected lamps are electrically interchangeable; the use of exclusionary lamp holders will prevent mechanical interchangeability.

Protected lamps are usually designed for universal or vertical

burning. They are rated slightly lower in lumen output compared to standard vertical burning lamps. 3.2.2 Mercury Lamps High-pressure mercury (vapour) lamp are high-intensity discharge lamp in which the major portion of the light is produced, directly or indirectly, by radiation from mercury operating at a partial pressure in excess of 100 kilopascals. NOTE: This term covers clear, phosphor coated (mercury fluorescent) and blended lamps. In a fluorescent mercury discharge lamp, the light is produced partly by the mercury vapour and partly by the layer of phosphors excited by the ultraviolet radiation of the discharge. Mercury lamps were first developed in 1901, but compact arc tube versions didn't appear until some 30 years later. They became widely used for roadway lighting after the development of long-life lamps in 1960 and began to be used for indoor general lighting after improved-color or "deluxe white" phosphors were introduced in 1966. The efficacy of mercury lamps that peaked at about 50 lumens per watt together with relatively poor depreciation characteristics has made the mercury lamp obsolete for energy-efficient lighting. It should not be used in new

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installations and existing installations should be upgraded to use a more energy-efficient source. 3.2.3 Low-Pressure Sodium Lamps Low-pressure sodium (vapour) lamps are discharge lamps in which the light is produced by radiation from sodium vapour operating at a partial pressure of 0.1 pascal to 1.5 pascal Low-pressure sodium (LPS) lamps use sodium as the primary light-emitting material. LPS lamps relatively have good performance characteristics and operate at higher efficacies than of fluorescent or other type of HID lamps. However, due to their relatively large physical size, difficult to control optics and monochromatic color (CRI=0). Limiting their application to security, roadway, tunnel & other similar application where color rendering and appearance are not of concern. 3.2.4 High Pressure Sodium Lamps High-pressure sodium (vapour) lamp are high-intensity discharge lamps in which the light is produced mainly by radiation from sodium vapour operating at a partial pressure of the order of 10 kilopascals. NOTE: The term covers lamps with clear or diffusing bulb. High-pressure sodium lamps were developed and introduced in 1968 as energy-efficient sources for exterior, security, and some industrial lighting applications. HPS lamps were mostly placed into roadway lighting service. HPS lamps are the most efficient of the HID lamp sources, and they are useful in most applications where high color rendering is not a crucial concern. Figure 3.5 shows the typical HPS lamp configurations. Unlike metal halide lamps, HPS lamps do not contain starting electrodes. Due to the HPS ballast's electronic starting circuit; warm-up and restrike periods are much shorter than those of metal halide lamps.

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Figure 3.5 Typical High Pressure Sodium Lamp Configurations

(a) Universal Burning Position. HPS lamps, unlike most metal halides, do not require enclosure except to prevent moisture from accumulating on the lamp. This makes HPS lamps especially easy to use in many fixture types. Moreover, the virtual insensitivity of HPS lamps to operating position means that fewer lamp types are needed, as compared to metal halide.

Lamp color temperature in HPS lamps does not vary much. While

the "deluxe" HPS lamp has a relatively light CRI (65) for HPS technology, its color temperature of 2100-2200 K is not much different from standard HPS, which varies between 1900 K and 2100 K. All HPS

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lamps except "white" sodium appear in golden-orange color, and are not recommended for non-industrial interior lighting.

HPS lamps are offered in variety of wattages. Lumens per watt,

ranging from 90 to 130, increase with wattage. Electronic ballasts are available in the market and will provide a small increase in system efficacy.

Some HPS lamps can be obtained with 2 arc tubes. These so called

“standby” lamps are a reasonable alternative to instant strike circuits, providing rapid restrike cycles while offering extended lamp life. It should be noted that lamp warm-up time would still be in effect in the event of a power interruption. However, the lamp will not have a cool down before the second arc can be struck. These lamps are especially applicable for roadway and parking lot applications. In normal operation, standby lamps alternate operation between the arc tubes.

Performance characteristics of screw base “Deluxe" HPS lamps with

their respective CRI are described in Appendix D, as well as standard screw base HPS lamps.

(b) Universal Position Directional HPS Lamps (See Appendix D).

R-configured HPS lamps are useful for compact directional light sources, such as track lighting and outdoor lighting luminaires. The poor color rendition of these lamps, however, limits the usefulness to specific industrial and security floodlighting and general lighting applications.

(c) Double-Ended HPS Lamps. The double-ended HPS was

designed to take advantage of luminaires and lighting installations originally designed for the double-ended metal halide lamp. The double-ended HPS lamp offers comparable lumen output, but offers HPS’ longer life and excellent lumen maintenance characteristics.

(d) White Sodium Lamps. White HPS lamps offer lamp life and

lumen maintenance characteristics similar to those of other HPS lamps whose color temperatures and CRI may be unsuitable for many interior spaces. However, ballast designs for “white” HPS lamps employ electronic circuits designed to increase color temperature and CRI. The color temperature, of white sodium lamps, at 2600 K to 2800 K, closely

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resembles incandescent lighting. During the lamp's stable color-life, the color performance is more consistent and appealing than most metal halide lamps (including 3000 K lamps). Although efficacy is relatively low 35-45 lumens per watt, the white sodium lamp is in many ways the best (if not the only high-efficacy substitute for incandescent lamps). 3.2.5 Ballasts and Ignitors HID lamps require ballasts to regulate the arc current flow and to deliver the proper voltage to the arc. Depending on the lamp design, some larger metal halide lamps employ a starting electrode within the lamp to initiate the arc. See Figure 3.1. Smaller metal halide and HPS lamps, on the other hand, do not contain starting electrodes. Instead, a high-voltage pulse to the operating electrodes starts the lamp. An external electronic starting circuit associated with the ballast generates this pulse. This circuit is commonly called an ignitor. A few electronic ballasts are now available for HID lamps. Electronic ballasts for HID lamps do not use the same principles as for fluorescent lamps. The primary benefit of electronic HID ballast is more precise management of the lamp’s arc tube wattage over life. By better managing the arc tube wattage, more consistent color and longer lamp life usually occur. With few exceptions, high-frequency operation does not increase HID lamp efficacy. 3.2.6 Lamp Dimming While it is technically possible to dim some HID lamps, the results are not likely to be satisfactory from either a functional or energy-saving standpoint. HID lamps are designed to be operated only at rated power. Anything less will compromise performance. This usually affects the efficacy, life and color. For example, a metal halide lamp can be dimmed to about 50% of rated power, but at this level it generates only about 25% of its rated lumens, and it will change color in an undesirable manner. HID dimming requires specialized ballasts and dimming electronics. Specifiers should carefully evaluate proposed systems with respect to warrantee responsibility in case of system performance problems.

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An exception is the step-dimming (hi-lo) systems for HPS and MH lamps. These systems provide full light then switch to a lower standby level via a special circuit in the HID ballast. They are typically supplied by the HID ballast manufacturer and can be linked to manual or automatic controls for use in warehouses, parking areas and other installations where continuous high-level lighting is not required. Standby levels of about 50% (input power) are typically available. Since, for the low setting, the HID lamp is already on, lamp warm-up times after switching to full output are relatively short. 3.2.7 Lamp Starting and Restrike HID lamps start in a “glow” state or at a very low output before reaching its full brilliance. Starting the arc initially may take a few seconds and the duration of the warm-up period can range from 2 to 10 minutes depending on the lamp and ballast characteristics. During this period, heat from the arc increases the arc tube temperature, causes the internal gas pressure to build and the metal compounds to melt and vaporize. As these gas mixtures enter the arc, they are ionized and emit energy. Even in brief power interruptions, HID lamps will extinguish. The lamp must cool down first before the arc restrikes again. Restrike period could create hazardous conditions especially when there are frequent momentary power failures or voltage dips. In this situation, several options may be applied such as using MH or HPS luminaires with “instant restrike” capability. These luminaires have special ballast or circuit, which develops very high voltages necessary to instantly restrike a hot HID lamp. Another option is by using HPS systems that have a second arc tube connected in parallel with the one in operation. Only one arc tube can operate at a time and in the event of momentary power failure, the “cool” arc tube begins to operate immediately upon the resumption of power. MH lamps that operate on standard MH ballasts with no auxiliary starting circuits contain three electrodes. Two main electrodes are mounted at the ends of the arc tube. At one end, an auxiliary or starting electrode is mounted next to the main electrode. The lamp begins the starting process when the gas between the main and starting electrode ionizes. After starting, a thermal switch in the lamp disables the starting electrode. Unlike conventional metal halide lamps, HPS lamps and the

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newer “pulse start” MH and ceramic arc tube MH do not contain starting electrodes. An external high voltage pulse circuit matched to the ballast characteristics initiates starting. The system used for HPS lamp-starting results in warm-up and restrike periods that are much shorter than those of metal halide lamps. 3.2.8 Lamp Life and Failure Modes. The lamp life and failure of HID lamps varies considerably depending on the type, burning orientation, size and configuration. Near the end of lamp life, many HID lamps will exhibit a noticeable degree of color shift, which may be objectionable in some applications.

3.2.8.1 Metal Halide. The subsequent blackening and failure of the arc tube or seals, or the loss of sodium through the wall of the quartz arc tube are due to cathode deterioration. Arc tubes in lamps that are burned continuously are more likely to rupture at end-of-life; manufacturers recommend that such systems be turned off at least once a week to minimize the chances of such failures.

3.2.8.2 Standard High-Pressure Sodium. Loss of sodium through

the ceramic wall of the arc tube causes the operating voltage of the lamp to rise beyond what the ballast can supply. The lamp then "cycles" on and off as the ballast tries unsuccessfully to maintain the arc. The arc tube seals can also crack and leak sodium into the space between the arc tube and outer bulb of the lamp.

3.2.8.3 Low-mercury HPS Lamps. These "unsaturated" HPS lamps drop significantly in light output when their sodium is lost. When this happens, color shifts to blue (depending upon design) which signal their end-of-life.

3.2.8.4 No-mercury HPS Lamps. Xenon may be used as substitute for mercury vapor as a buffer gas so that the arc tube of these HPS lamps contains only xenon and sodium. Xenon, however, shifts the chromaticity of the discharge towards green color appearance of these lamps.

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HID lamps offer some of the longest lifetimes of any light Source. Incandescent and Fluorescent lifetimes are shown here

0 10 20 30 40

Source: Manufacturer data

Typical rated lifetime (thousands of hours)

1814

20

High-pressure sodium White HPS 7.5 Standard HPS 40

24

Low-pressure sodium 16

Double Arc-tube

7.6 Metal halide

1

24 16

Mercury vapor

20 7.5 3

Incandescent Fluorescent

Figure 3.6 Life of HID Lamps 3.2.9 Energy Efficiency. HID lamps are among the most energy-efficient lamp technologies available. The most efficacious HID sources are standard high-pressure sodium lamps, ranging from 65 (40-watt lamp) to about 130 lumens per watt (1000-watt lamp). Metal halide lamps range from 55 (40-watt open fixture lamp) to 110 lumens per watt for a 1000-watt horizontal high-output lamp. White sodium lamps have the lowest efficacy of the HID sources, producing between 40 and 50 lumens per watt (about the same as a CFL). These values include ballast losses, and they are based on new, but burned-in lamps. As a safety measure, HID lamps should not be operated 24 hours a day and 7 days a week.

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High-pressure sodium Metal halide

Low-pressure sodium

White sodium Mercury vapor

Compact fluorescent 5-26 W Compact fluorescent 27-40 W Fluorescent (full size and U-tube)

Standard incandescent Tungsten halogen Halogen infrared reflecting

0 20 40 60 80 100 120 140 Efficacy. Including ballast (lumens per watt)

Figure 3.7 Graphical Comparison of Different Lamp Efficacy 3.2.10 Color Characteristic. Manufacturers have taken advantage of new technologies in recent years to improve color characteristics of HID lamps considerably. This development has allowed lighting professionals to use HID lamps in an ever-widening range of applications. In terms of lamp Correlated Color Temperature (CCT) and Color Rendering Index (CRI) capabilities, HID lamps can be summarized as follows:

(a) Metal Halide Lamps. Some metal halide lamps are available in 2400-3200 K (warm), but most lamps range from neutral to cool in color appearance, with a crisp white light of 3500-4300 K. Color rendering indices are usually between 65 and 40, although a few of the more recently developed lamps achieve very high CRI (up to 96).

(b) High Pressure Sodium Lamps. Most HPS lamps have a

distinctive, golden orange color of 1900-2100 K, accompanied by a relatively poor CRI of less than 25. There are a few "deluxe" HPS products with a CRI of 65. In addition, "white" sodium lamps have color temperatures of 2500-2800 K and a CRI over 45. Neither deluxe nor white sodium lamps are as efficacious or as long lasting as standard HPS lamps.

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3.2.11 Temperature Sensitivity. Metal halide lamps are sensitive to low starting temperatures, and lamp life will be reduced if they are frequently started below -12 0C. High-pressure sodium lamps are fairly insensitive to temperature, and will start to about -30 0C. 3.2.12 Burning Orientation. Many HID lamps are designed to operate in a specific burning position, such as universal, horizontal, vertical with base up and vertical with base down. Lamp manufacturers usually designate the correct burning position for position-sensitive lamps in their catalogs. Operating HID lamps in burning positions other than those recommended by the manufacturer will adversely affect lamp life and lumen output. In particular, some metal halide lamps are extremely sensitive to burning position. High-pressure sodium lamps generally are not. 3.2.13 Other Applicable Technologies. HPS and metal halide lamps are the highest efficacy point sources in moderate output lumen packages. However, in certain situations, other sources might be more applicable, these include:

Metal halide lamps using ceramics instead of glass to enclose the arc. These lamps are especially useful for display illumination and are generally available only in the lower wattage ranges.

Compact and linear fluorescent lamps, particularly in general lighting and wall-washing situations

3.2.14 HID Ballasts When HPS lamps were developed, lamp life was found to be dependent upon the ballast being able to compensate for the changes in lamp electrical characteristics as the lamp burned. In typical systems, due to changes in lamp voltage over time, HPS lamps initially operate at less than rated watts, then lamp watts increase to above rated values and finally, as the lamp approaches end-of-life, lamp watts again fall below rated values. That makes HPS ballast circuits somewhat more costly and complicated. Add to that was the need to have a high-voltage pulse applied to the lamp for starting. Now, of course, pulse-start metal halide

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lamps also require a starting pulse so both HPS and metal halide ballasts must have starting ignitor circuitry. Depending upon the lamp, the best match between the power system, the ballast and the HID lamp for a given application therefore requires consideration of:

• Lamp watts and nominal line voltage. Determines the basic size, weight and circuit type of the ballast.

• Variation of the line voltage. How does the voltage available to the ballast change during the operating period? Determines the ballast "voltage regulation" characteristics required.

• Input voltage "dip" tolerance. Transient changes in the input voltage that may cause the lamp to extinguish.

• Power factor requirements. Affects building power quality, system load and utility costs.

• Lamp wattage regulation. How well does the ballast control the power flowing to the lamp and therefore the lamp light output?

• Ballast losses. Affects luminaire temperatures, system efficiency and therefore operating costs.

• Line current (starting and open circuit). Especially important during lamp warm-up when ballasts may draw higher than average current. The electrical system must be sized to handle the maximum current and only a certain maximum number of ballasts can be used per circuit.

• Current crest factor. Defined as the ratio of the peak lamp current to the root-mean-square (rms) value. Values of 1.4 to 1.6 are ideal. Higher values negatively affect lamp depreciation and life.

• System operation when there are rare or abnormal conditions such as short circuits or momentary power interruptions or when the lamp reaches end-of-life.

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3.2.15 Interchangeable Lamps. Metal halide lamps have superior color when compared to either mercury vapor or high-pressure sodium technologies. For interior spaces where either of the poorer color lamps was originally used, it may be desirable to retrofit with metal halide without having to change the ballasts in the existing luminaires. Specific products are available in a few configurations and wattages to serve this function. Similarly, some high-pressure sodium lamps can be retrofitted into existing mercury vapor luminaires, particularly roadway lightings, with reduced wattage and substantially increased lumen output. Performance characteristics of exchangeable metal halide and HPS lamps are noted in Appendix D.

3.3—APPLICATION GUIDELINES . HID lamps are point sources that lend themselves to projection and floodlighting situations, as well as to general illuminations. The best interior applications are those where lights are left on for long periods or are controlled by a time switch. Examples would include manufacturing, corridor, and display lighting, as well as commercial area lighting. Some of the best applications for HID lamps are in all kinds of exterior lighting sources. HID sources are especially suitable for roadway, architectural, landscape, parking lot, security, and sports lighting. 3.3.1 Typical Applications. In general, HID lamps are best applied in one of the following ways:

• Energy-Efficient Flood and Display Lighting. In suitable

modern luminaires, HID lamps can be used for a wide variety of display and floodlighting situations, including track, recessed, and surface installations.

• Energy-Efficient Lamps in General Lighting Luminaires. As long as switching is not a concern, wide opportunities are possible in using HID lamps for area lighting in both interior and exterior situations. HID lamps are particularly well

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suited to large rooms with high ceilings, such as gymnasiums, industrial plants, and warehouses.

(a) General Limitations. All HID lamps require warm-up and

restrike periods, so applications requiring frequent switching should not utilize HID lamps. Additionally as noted previously, lamps of these types can only be dimmed with highly specialized dimmers and ballasts. The effort of dimming is not nearly as appealing or as extensive as it is with incandescent or fluorescent light sources. Lamp efficacy and color stability may suffer when HID lamp are operated at less than full output.

(b) Residential Applications. Because frequent switching is

common to residential operation, HID lamps are not commonly used in homes. Nevertheless, low-wattage HID lamps may be useful in outdoor security and landscaping lighting applications, particularly if timers or photoelectric sensor control these sources.

(c) Commercial Applications. HID lamps offer the designer an

alternative to incandescent down-lights, up-lights, and accent lights. Unlike fluorescent alternatives, HID lamps are point sources of light that give sparkle to polished surfaces and produce dramatic shadowing when used to accent displays. The compact lamp size of the smaller HID lamps allows for the use of many traditional luminaire types and shapes while employing a reasonable lumen package.

(d) Special Interior Applications. The best interior applications

for HID lamps are for corridor and lobby down-lighting, commercial wall washing, lobby and office up-lighting, and commercial and general lighting. The smaller HID lamps are valuable in accent and display lighting applications, as well. In addition, some types of highly decorative fixtures, such as wall sconces and pendant chandeliers, can be designed for compact HID lamps

(e) Exterior Applications. There is a wide range of exterior

applications for HID lamps. In addition to those listed previously, HID lamps can be used in many landscape applications, such as bollards and tree up-lights, as well as in wall lights, step lights, and architectural facade and floodlighting luminaires. The large 1500-watt metal halide lamp with a lamp life of 2000 to 3000 hours is widely used in sports lighting applications where television cameras are used.

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3.3.2 Special Application Considerations for HID Lamps. There are several precautions to consider when using HID lamps in certain situations. Manufacturers' literature on this subject is extensive, and troubleshooting guides and engineering and technical bulletins are available. Some of the most important considerations are noted here.

• Backup lighting. In HID applications where a brief power outage could cause hazardous conditions or a major manufacturing shutdown, and where no backup non-HID emergency lighting system is in place, it's a good idea to specify that some portion of the luminaires be furnished with either instant-restrike or quartz backup lamps. This ensures that some type of backup lighting is in place until the HID lamps can be reignited.

• Strobe effects. All HID lamps are turned on and off 120 times per second in synchronization with the 60-Hz alternating current power supply, both with electromagnetic and typical electronic HID ballasts. Because of this, the use of HPS lamps in general lighting luminaires near rotating machinery may produce a stroboscopic effect, making the machinery appear to be motionless, a potentially hazardous situation. This can occur when the moving object rotates at any speed that is a multiple of 60 (for example, 2400 revolutions per minute). Strobe effects of this type can be mostly eliminated by the proper phasing of the luminaire power supply circuits, so that none of the machinery is lighted solely by luminaires on the same phase circuit.

3.4—EXAMPLE A high ceiling hotel lobby might employ recessed incandescent down-lights supplied with 250-watt PAR-38 quartz lamps to provide general illumination for the space. If, instead, 40-watt double-ended metal halide (3000K, 81 CRI) electronically ballasted lamps were used, the following benefits could be realized:

More than 160 watts per socket saved, including ballast losses Fewer luminaires needed due to increased lumen output (5500

lumens to 3300 lumens)

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Decreased maintenance charges for relamping due to increased lamp life of 64% (10 000 hours to 6000 hours)

The metal halide luminaires in this application will use much less energy than the incandescent down-lights, while providing an essentially similar aesthetic to the hotel lobby. Although the initial costs for luminaires and lamps will be higher than would be the case for the incandescent design, the reduced quantity of luminaires needed, combined with the energy savings achieved by the design, will more than offset the higher start-up cost, while producing significant long-term savings.

Table 3.2 Typical Application of HID Lamps

Application

Metal Halide

High- pressureSodium

White High-

pressureSodium

Low-pressureSodium

Mercury Vapor

Interior: decorative down lights

a

Parking areas General outdoor Roadway/tunnel

Sports Arena High-bay spaces (Hangars, Warehouse, etc.)

a

Low-bay spaces (Supermarkets, light industrial shops, etc.)

Outdoor signage

a

NOTE: a - where access is difficult or dangerous

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Chapter 4. Light-Emitting Diodes

INTRODUCTION Almost everyone is familiar with light-emitting diodes (LEDs) from their use as indicator lights and numeric displays on consumer electronic devices, and later used in seven-segment alphanumerics that became briefly popular in digital watches and other display applications during the early 1970s.

Figure 4.1 Light Emitting Diode Anatomy

4.1—INVENTION AND DEVELOPMENT

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In 1906, Henry Joseph Round first reported “electroluminescence” while experimenting with Silicon Carbide (SiC). In 1955, Rubin Braunstein (born 1922) of the Radio Corporation of America first reported on infrared emission from Gallium Arsenide (GaAs) and other semiconductor alloys. In 1962, Nick Holonyak Jr. (born 1928) of

CHAPTER 4. LIGHT-EMITTING DIODES

General Electric Company invented the first practical light-emitting diode operating in the red portion of the visible spectrum. Throughout the later 1960s and 1970s, further invention and development produced additional colors and enabled LEDs to become a readily available commercial product.

4.2—HOW LEDs WORK Basically, LEDs are solid-state semiconductor devices. A semiconductor is a material with a varying ability to conduct electrical current. When certain elements (see Table 4.1) are combined in specific configurations and electrical current is passed through them, photons (light) and heat are produced. The heart of LEDs, often called a “die” or “chip,” is composed of two semiconductor layers – an n-type layer that provides electrons and a p-type layer that provides holes for the electrons to fall into. The actual junction of the layers (called the p-n junction) is where electrons and holes are injected into an active region. When a sufficient voltage is applied to the chip across the leads of the LED and the current starts to flow, electrons in the n region have sufficient energy to move across the junction into the p region. Once in the p region the electrons are immediately attracted to the positive charges due to the mutual Coulomb forces of attraction between opposite electric charges. When an electron moves sufficiently close to a positive charge in the p region, the two charges “recombine”. When the electron and holes recombine, photons (light) are created (Figure 4.2). The photons are emitted in a narrow spectrum around the energy band gap of the semiconductor material, corresponding to visible and near-UV wavelengths.

Table 4.1 Elements Important to the Construction of LEDs

Base materials p-type dopants n-type dopants Boron (B) Aluminum (Al) Carbon (C) Silicon (Si) Gallium (Ga) Nitrogen (N) Germanium (Ge) Indium (In) Phosphorus (P)

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Figure 4.2 LED Structure

4.3—COLOR

The color-emitted light of LEDs depends on the chemical composition and dominant wavelength of the semiconducting material used. LED development began with infrared and red devices made with GaAs. Advances in materials science have made possible the production of devices with even shorter wavelengths, producing light in a variety of colors. Table 4.2 lists some common light emitter materials, the emission wavelength and corresponding energy gap. The first materials, GaP and AlAs, are used to make emitters in the visible portions of the spectrum. The next three materials, GaAs, InP, and AlGaAs, are used to make emitters in the near infrared portion spectrum. The last material, InGaAsP is used to make emitters in the infrared portion spectrum. The energy gap corresponds to the energy of the emitted photons and also is indicative of the voltage drop associated with a forward biased LED.

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Table 4.2 Common Light Emitter Materials and Characteristics

Material Formula Energy Gap Wavelength

Gallium Phosphide GaP 2.24 eV 550 nm Aluminum Arsenide AIAs 2.09 eV 590 nm

Gallium Arsenide GaAs 1.42 eV 870 nm Indium Phosphide InP 1.33 eV 930 nm

Aluminum-Gallium Arsenide AIGaAs 1.42-1.61 eV 770-870 nm

Indium-Gallium-Arsenide-Phosphide InGaAsP 0.74-1.13 eV 1100-1670 nm

4.3.1 Tri-color LEDs The most popular type of tri-color LED has a red and a green LED combined in one package with three leads. They are called tri-color because mixed red and green light appears to be yellow and this is produced when both the red and green LEDs are on. The diagram shows the construction of a tri-color LED. Note the different lengths of the three leads. The center lead (k) is the common cathode for both LEDs, the outer leads (a1 and a2) are the anodes to the LEDs allowing each one to be separately, or both together to give the third color.

Figure 4.3 Tri-Color LED

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4.3.2 Bi-color LEDs A bi-color LED has two LEDs wired in ‘inverse parallel’ (one forwards, one backwards) combined in one package with two leads. Only one of the LEDs can be lit at one time and they are less useful than the tri-color LEDs described above.

Figure 4.4 Bi-Color LED

Assembled as an LED, phospides and nitrides of aluminum, indium, and gallium produce lights of different colors and efficacies. The two major material groups are the Indium-Gallium Phospide (InGaP) compounds, used to create red and amber, and the Gallium Nitride (GaN) compounds, used to create blue, cyan, and green. These LED materials can also generate infrared and ultra-violet radiation outside the visible range. The plastic may be colored, but this is only for cosmetic reasons or to improve the contrast ratio; the color of the packaging does not substantially affect the color of the light emitted. LEDs that emit different colors are made of different semi-conductor materials, and require different energies to light them.

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Table 4.3 Color Producing Inorganic Semiconductor Materials

Color Production Inorganic Semiconductor Materials

Red and infrared

Aluminum Gallium Arsenide (AlGaAs)

Green

Aluminum Gallium Phospide (AlGaP)

Orange-red, orange, yellow, and green

Aluminum Gallium Indium Phospide (AlGaInP)

Red, red-orange, orange, and yellow

Gallium Arsenide Phospide (GaAsP)

Red, yellow, and green

Gallium Phospide (GaP)

Green, pure green (or emerald green), and blue

Gallium Nitride (GaN)

Near ultraviolet, bluish-green, and blue

Indium Gallium Nitride (InGaN)

Blue

Silicon Carbide (SiC) as substrate, Silicon (Si) as substrate, Sapphire (Al2O3) as substrate, Zinc Selenide (ZnSe)

Ultraviolet Diamond (C) Near to far ultraviolet

Aluminum Nitride (AlN), Aluminum Gallium Nitride (AlGaN)

4.4—SIZES, SHAPES AND VIEWING ANGLES LEDs are available in a wide variety of sizes and shapes. LED die sizes range from tenths of millimeters for small-signal devices to greater than a square millimeter for the power packages available today The ‘standard’ LED has a round cross-section of 5 mm diameter (T-1 ¾ lamp) “bullet shape” and this is probably the best type for general use, but 3 mm round LEDs are also popular.

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Round cross-section LEDs are frequently used and they are very easy to install on boxes by drilling a hole of the LED diameter, adding a spot of glue will help to hold the LED if necessary. LED clips are also available to secure LEDs in holes. Other cross-section shapes include square, rectangular and triangular. As well as a variety of colors, sizes, and shapes, LEDs also vary in their viewing angle (beam of light spreads out). Standard LEDs have a viewing angle of 60° but others have a narrow beam of 30° or less.

Figure 4.5 LED Shapes

4.5—LUMINOUS FLUX AND EFFICACY The luminous flux from a LED varies according to its color, and depends on the current density the LED die can manage. Package properties also limit the electrical current that can be safely driven through LED assemblies. The more current an LED device can handle, the more luminous flux it will produce. The efficacy of individual LEDs varies by material type, packaging, radiation pattern, phosphors, and processing. The average commercial LED currently provides 32 lumens per watt (lm/W), and new technologies promise to deliver up to 100 lm/W. Most typical LEDs are designed to operate with no more than 30-60 milliwatts of electrical power. Around 1999, commercial LEDs capable of continuous use at one watt of input power were introduced. These

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LEDs used much larger semiconductor die sizes to handle the large power input. In 2002, 5-watt LEDs were available with efficiencies of 18-22 lumens per watt. In 2005, 10-watt units became available with efficiencies of 60 lumens per watt. These devices will produce about as much light as a common 50-watt incandescent bulb, and will facilitate use of LEDs for general illumination needs.

4.6—LUMEN DEPRECIATION Lumen depreciation is the lighting attribute most often used to determine the useful life (minimum maintained illuminance level) of LED sources. LEDs do not fail abruptly; instead, they dim with time. Although a 50,000 to 100,000-hour life is commonly attributed for LED. The best LED achieved 70 percent of original light output at 50,000 hours of operation under standard use conditions. One of the key limitations affecting LEDs is temperature. A common maximum junction temperature rating is more than 130oC. The higher the design junction temperature, the faster the light output will degrade. LEDs of different colors do not have identical lumen depreciation rates. Various packaging materials and manufacturing methodologies can also influence depreciation rates in the same base color.

4.7—POWER SOURCE LEDs are low-voltage current-driven devices. It operates at relatively low voltages between 1 to 4 volts, and draw currents between 10 to 40 mA. Voltages and currents substantially above these values can melt a LED chip. Power sources include electronic circuit choices such as drivers and switch-mode power supplies. A single direct-current (dc) power source may drive one LED or a cluster of LEDs. Unlike incandescent light bulbs, which light up regardless of the electrical polarity, LEDs will only light with correct electrical polarity (see Table 4.4). When the voltage across the p-n junction is in the correct direction, a significant current

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flows and the device is said to be forward-biased. If the voltage is of the wrong polarity, the device is said to be reverse biased, very little current flows, and no light is emitted. LEDs can be operated on an AC voltage, but they will only light with positive voltage, causing the LED to turn on and off at the frequency of the AC supply. Because the voltage versus current characteristics of an LED are much like any diode, they can be destroyed by connecting them to a voltage source higher than their turn-on voltage. Most LEDs have low reverse breakdown voltage ratings, so they will also be damaged by an applied reverse voltage of more than a few volts.

Figure 4.6 LED Configuration

Table 4.4 Determination of LED Correct Polarity

Polarity positive negative Sign + -

Terminal anode cathode Wiring red black Pinout long short Interior small large Shape round flat

Marking none stripe

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4.8—ADVANTAGES OF USING LEDs

LEDs are capable of emitting light of an intended color without the use of color filters that traditional lighting methods require. The shape of the LED package allows light to be focused. Incandescent and fluorescent sources often require an external reflector to collect light and direct it in a useable manner. LEDs are insensitive to vibration and shocks, and they are solid-state devices that do not use gases or filaments. Thus extremely high reliability against mechanical shocks and vibrations are achieved. LEDs are built inside solid cases that protect them, making them hard to break and extremely durable and moisture-tolerant. However, the electronic circuitry (drive circuitry/power) that surrounds them in a system is not. Since LEDs are low-voltage devices, LED systems are safer than other lamp systems that require high voltages. In addition, visible-wavelength LEDs do not generate appreciable amounts of ultra-violet or infrared. LEDs have an extremely long operating hours, twice as long as the fluorescent lamps and fifty times longer than the incandescent bulbs. Further, LEDs fail by dimming over time, compared with the abrupt burn-out of incandescent bulbs. LEDs give off less heat than incandescent light bulbs with similar light output. LED lights up very quickly and will achieve full brightness in approximately 0.01 seconds, 10 times faster than an incandescent light bulb (0.1 second), and many times faster than a compact fluorescent lamp, which starts to come on after 0.5 seconds or 1 second, but does not achieve full brightness for 30 seconds or more.

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4.9—DISADVANTAGES OF USING LEDs LEDs are currently more expensive than more conventional lighting technologies. The additional expense partially stems from the relatively low lumen output (requiring more light sources) and drive circuitry/power supplies needed. LED performance largely depends on both current density and junction temperature. More light output degradation occurs whenever either of these parameters is increased. It is very important that the specified LED junction temperature not be exceeded for effective LED system operation. Adequate heat sink is required to maintain long life.

4.10—LED APPLICATIONS While LEDs may be more expensive than incandescent lights up front, because they’re built around advanced semiconductor material, their lower cost in the long run can make them a better buy. The main drivers for conversion to LEDs are higher efficiency, long life, reduced maintenance, and increased and superior visibility, making LEDs a more cost-effective lighting option for a wide range of situations. Below are examples of different usage of LEDs.

(a) seven segment in showing numbers in calculators and measurement instruments.

(b) in dot matrix arrangements for displaying messages displays in public information signs (banks, hotels, airports and railway stations and as destination displays for trains, buses, and ferries).

(c) remote controls for TVs, VCRs, etc., using infrared LEDs. (d) traffic signals (e) pedestrian signs (f) highway sign panels (g) railroad signals (h) marine navigational lights (i) emergency beacon or strobe lights at airports (j) exit signs

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(k) channel letters (l) street signs (m) moving messages (n) marquis (o) building façade graphics (p) scoreboards. (q) walkway lighting (r) floor of spaces that are often dark or that only have low-

level lighting (movie theaters and passenger aircrafts) (s) car brake and indicator lights in automobile (t) bicycle lighting (u) task lighting for desks, workstations, and display-cases (v) downlighting for elevators and emergency applications (w) appliance lighting for refrigerators and vending machines (x) portable lighting for flashlights or torches (y) miners’ and dive lights. (z) indicators for audio and video equipment. (aa) fiber optic communications (ab) in photographic darkrooms (ac) backlights for LCD screens. (ad) disco/club lighting products. (ae) projectors (af) movement sensors (i.e. in mechanical and computer mice

and trackballs) (ag) pulse oximeters, both a red and an infra-red LED are used. (ah) phototheraphy (use of light for healing process) (ai) christmas lights and other for decorative display.

Figure 4.7 Seven-segment LED

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Figure 4.8 Dot matrix LED

Figure 4.9 Exit and Emergency Sign Backlight LED

Figure 4.10 Cyclist Belt LED

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Figure 4.11 LED for Task Lighting

4.11—ENVIRONMENTAL AND DISPOSAL ISSUES As LED systems become more efficient, the environmental benefits from decreased energy consumption will increase. Since LEDs are solid-state devices, they do not contain mercury, glass, filaments, or gases. Because LEDs are small and have long lifetimes, their use might reduce the material flow entering the waste-stream.

4.12—LEDs: THE FUTURE OF LIGHTING LEDs are finding their way into many new applications within the lighting community. Research by dozens of companies is underway to deploy LEDs even further. The ultimate goal is to move these special light sources into common usage for general lighting wherever applicable.

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Chapter 5. Energy-Efficient Fluorescent Ballasts

INTRODUCTION Advances in fluorescent lamp ballast technology have created opportunities for improved lamp performance and increased system energy efficiency of lamp and ballast. Products, such as high frequency electronic ballast and heater cutout ballasts are now widely available and accepted in the marketplace. The recent trend toward more competitive pricing of these products should continue, due to an expansion of manufacturing facilities and more competition between manufacturers. Energy-efficient ballasts are an excellent energy-saving strategy that should not be overlooked by anyone who is interested in saving money through the use of efficient lighting products. The most prevalent fluorescent fixtures found in general commercial lighting today employs the rapid start F40T12 lamp/ballast combination. However, the more efficacious smaller diameter F36T8 lamps are gaining popularity in general lighting applications and as an energy-efficient replacement for standard lamps. This Chapter mainly addresses electronic ballasts that operate linear fluorescent lamps at high frequencies, but it also covers energy-efficient electromagnetic ballasts with heater-cutout circuits that switch off a lamp’s electrode heaters after startup.

5.1—TECHNOLOGY DESCRIPTION 5.1.1 Lamp Ballasts To generate light output of a fluorescent lamp, a control gear generally known as “ballast” is needed to provide sufficient voltage for start-up across the end electrodes of the lamp, to maintain constant current during

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CHAPTER 5. ENERGY-EFFICIENT FLUORESCENT BALLASTS

steady state operation of the lamp, and to maintain stable voltage across the lamp during supply voltage fluctuations. Lamp ballasts are designed to meet the voltage and current requirement for every specific type of fluorescent lamp for the optimum operation of the lamp and ballast combination. Good quality ballast accounts for 15% of the lamp and ballast total energy consumption while the poor quality ballast can account as high as 30%. It is therefore very important to consider energy efficient ballast when choosing lamp and ballast optimum combination. Well-designed electronic lamp ballast that are presently in the market makes for an energy efficient alternative to the electromagnetic ballast. The high frequency operation of the fluorescent lamp when used in connection with electronic ballast allows up to 10% increase of light output using the same level of energy consumption compared with electromagnetic ballast. The cost, however, is prohibitive. It can go as high as 6 to 10 times more expensive than the energy efficient electromagnetic ballast. 5.1.2 Types of Fluorescent Lamp Ballasts

(a) Electromagnetic Ballast. Electromagnetic ballasts (Fig. 5.1) are also known as "core-and-coil ballasts", "choke ballast", "conventional ballast" and "ferromagnetic ballast". They use a heavy magnetic core of several laminated steel plates wrapped with copper windings. These types of ballasts are inexpensive to manufacture. The electromagnetic type of ballast is the predominantly use ballast in the country.

The Lighting and Appliance Testing Laboratory of the Philippine

Department of Energy provides regular updates of the list of PNS compliant electromagnetic ballasts. This list can be readily obtained from the laboratory for reference or from the DOE-CWPO (Department of Energy, Consumer Welfare and Protection Office). The list provides complete information on the ballast loss category of all electromagnetic ballast tested and available in the market.

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Figure 5.1 Typical Electromagnetic Fluorescent Ballast

(b) Energy Efficient Electromagnetic Ballast (Low Loss Ballast). Low loss ballasts contain a magnetic core of several laminated high grade (usually silicon) steel plates, wrapped with high-grade copper windings. By utilizing high quality materials the heat generated by the ballast is greatly reduced resulting to lower losses and increase in energy efficiency. New production technology and use of more energy efficient materials reduce ballast energy consumption by 50% (about 5W to 10W loss for each ballast) compared to the commonly used low quality electromagnetic ballast, as shown in Table 5.1 below.

Table 5.1 Ballast Loss Comparison

Type of Ballasts 18/20 watts Flourescent Lamps

36/40 watts Flourescent Lamps

Conventional Electromagnetic

10-12 watts 12-20 watts

Low-Loss Electromagnetic

6-8 watts 6-8 watts

Electronic 2-4 watts 2-4 watts Source: Department of Energy – Lighting and Appliance Testing Laboratory

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(c) Cathode-Disconnect Ballasts. Cathode-disconnect ballasts are

also known as "hybrid ballasts", "low-frequency electronic ballasts", and "filament cutout ballasts". These ballasts use magnetic core and coil transformer and an electronic switch for electrode-heating circuit. The electrode-heating circuit disconnects after the lamp starts.

(d) High Frequency Electronic Ballasts. Electronic ballasts, also

called "solid-state ballasts" operate fluorescent lamps at frequencies above 20 kHz using electronic switching power supply circuits.

Electronic high-frequency ballasts increase lamp-ballast efficacy,

leading to increased energy efficiency of the fixture and lower operating costs. Electronic ballast converts the 60Hz input frequency to above 20kHz to the lamp circuit. Electronic ballast that operates at high frequency increases lamp efficacy by 10% to 15% compared to 60Hz operation. See figure 5.2 below.

Figure 5.2 Lamp Efficacy vs. Frequency (Adapted from Thorn Lighting Manual)

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Electronic ballasts have a number of other advantages over electromagnetic ballasts. Electronic ballasts are readily available that operate three or four lamps, allowing the use of a single ballast in three-lamp and four-lamp luminaires. This reduces both installation and field wiring labor costs, and may negate the necessity of tandem luminaire wiring. Electronic ballasts are designed to operate lamps in either series or parallel mode. The advantage of the parallel mode of operation is that a single lamp failure will not affect the operation of the remaining lamps controlled by the same ballast. However, ballast losses will increase slightly in the parallel mode. Other advantages of the electronic ballast include reduced weight, quieter operation, and reduced lamp flicker. Electronic ballasts are directly interchangeable with electromagnetic ballasts, and they are available to operate most full-size and compact fluorescent lamps.

5.1.3 Starting Requirements To attain the most efficient lamp ballast combination it is recommended that the ballast can start the lamp successfully at rated starting voltage and current.

PNS IEC 60081: 2006 (IEC published 2002) provides complete data for each lamp and the required ballast for each corresponding lamp. This same standard provides the required starting voltage and current for each lamp type. New generations of lamps are not included under this standard. It is, therefore, important that the manufacturer be requested to provide the required data. 5.1.4 Operating Requirements When lamps are successfully started, the economical and optimum utilization is not guaranteed if the required operating voltage and current are not maintained.

PNS IEC 60081: 2006 (IEC published 2002) provides the data for proper lamp and ballast matching. The new generations of lamps are not covered under this standard, which makes it more difficult to make proper matching of lamp and ballast.

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The ballast to be used should always match the starting requirement of the lamp.

Example: For a rapid start lamp, rapid start ballast is needed. Sometimes lamps are specified to be rapid start and at the same time preheat start, in cases like this, either a preheat type ballast or rapid start type ballast can start the lamp. 5.1.5 Lamp and Ballast Wattage Compatibility To attain optimum lamp and ballast operation the lamp wattage should always match with the ballast wattage rating. Example: An 18W/20W lamp should not be used for 36W/40W ballast. In some cases a 32W lamp is used for 40W ballast. This makes the lamp filament current operate higher than the designed value thus causing premature lamp failures due to over stress of the filament.

Lamp wattage and lamp starting requirement must always be matched to ensure optimum lamp and ballast operation. Example: a 36W lamp must have 36W ballast, carefully considering as well the starting requirement of the lamp. The most common issue now is utilizing a 36W lamp for 40W ballast. Aside from the issue of starting requirement to attain optimum operation, the issue of mismatch rating has to be resolved since it may possibly reduce the service life of the lamp. (See Table 5.2)

Table 5.2 Effects of Mismatching Ballast and Lamp Types

Type of Lamp

Pre-heat Ballast

Rapid-start Ballast

Instant-start Ballast

Pre-heat Lamp

Normal operation

Unreliable starting

Unreliable starting;

Shortened lamp life

Rapid-start Lamp

Normal operation Normal operation

Shortened lamp life if cycle time

is short Instant-start

Lamp Will not start Will not start Normal operation

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5.1.6 Direct Lamp Change over using the Existing Installed Ballast Care must be taken when an attempt to change T12 40W lamp with T8 36W lamp using the existing installed ballast.

Most ballasts in old buildings are designed to operate T12 40W lamp and most of these were manufactured even before T8 36W were introduced to the market. Meaning, most of these (old installed ballast) are not designed to operate T8 36W lamps.

Sometimes it is possible to make a direct change over of a lamp without changing the ballast. However, this does not guarantee optimum lamp and ballast operation.

Lamp starting requirement sometimes hinders the proper starting of 36W T8 lamp when used to directly replace the 40W T12 lamp due to differences in the gas composition inside the lamp. 36W T8 lamp utilizes heavier gas inside the tube, which results to starting problems when direct replacement is done.

The optimum operation of lamp and ballast cannot be attained when the lamp and ballast are not properly matched. Problems such as early failure of lamp and hard starting of lamp may result. 5.1.7 Efficient and Cost-Effective Lamp and Ballast Changeover To attain optimum lamp and ballast operation from the change over of 40W lamp to 36W lamp, it is recommended that well designed 36W electronic ballast should to be used. A cheaper alternative is the new generation 36W energy efficient design of electromagnetic ballast.

Most 36W lamp operates very well in connection with well-designed 36W electronic ballasts.

Ballasts (electromagnetic and electronic) which have passed the safety and performance requirements of the Philippine National

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Standards/International Electrotechnical Commission Standards (PNS/IEC) shall always be used in retrofit/new installations.

An example of the cost effectiveness in re-lamping and switching to electronic ballast is shown in Table 5.3 below.

Replacing 2x40W FL with 2x32W FL& Installation of Electronic Ballast

Table 5.3 Example on Cost Effectiveness in Re-Lamping and Use of Electronic Ballast

No. of Fixtures Considered

Total Lamp & Ballast Wattage (W)

Total Lighting Load (kW) (A x B)

Energy Consumption @ 6k hrs/yr (kWh) (C x 6k)

Energy Savings @ 6,000 hrs/yr (kWh) (D1 – D2)

Annual Monetary Savings @ Pesos 10.00/kWh

Investment

Php 250/pc of 32 W Fluorescent Lamp

Php1,000/pc of Electronic Ballast

Total Investment (G + H)

Payback (years) (I / F)

Existing2 x 40 W FL

Replacement2 x 32 W FL

500 500

90 70

45 35

270,000 210,000

60,000

600,000

250,000

500,000

750,000

1.25

A

B

C

D E F

G

H I

J

5.1.8 Types of Conventional Ballasts and their Associated Starting Methods The methods of starting fluorescent lamps are presented in the order in which they were developed and used. The preheat method was introduced with the original fluorescent lamp in 1938, followed by the instant-start method introduced in 1944. However, because of the disadvantages listed for these methods, the vast majority of fluorescent lighting installed at the present use the third method introduced in 1952, which is rapid start.


Fluorescent lamps require a ballast to regulate the electric current through the lamp. For optimum performance, a particular ballast must match a specific lamp's current requirements. Generally, there are three different types of conventional ballasts. Listed below are the three types and their methods of operation.

(a) Preheat. This is also called switch start ballast. All ballasts that operate in this mode are electromagnetic ballasts. In so called “switch start” or preheat mode operation, a switch or starter establishes a complete circuit through the ballast to preheat the filaments for several seconds prior to initiating discharge (Figure 5.3). When the filaments have heated up, the starter opens and the ballast then provides a suitable voltage of approximately 200 to 300 volts to light the lamp and limits the current flow to the proper value. This process causes the lamp to flash on and off for several seconds before finally staying lit. Lamps with either Low or High resistance cathodes can be operated on switch start circuits.

mains voltage B

S B = ballast to limit the discharge current

S = starter/switch for lamp ignition

Figure 5.3 A Typical Switch Start Circuit

(b) Instant Start Ballasts. Instant start ballasts start the lamps by supplying high voltage (usually above 400V) to the lamp electrodes without preheating resulting to forced discharge. The high voltage applied across the lamps typically ignites them within 50 milliseconds. Electrodes are not preheated during starting which greatly reduce the service life of the lamp, which is inversely proportional to the number of starts (more starting reduces lamp life). On the other hand since lamp operates without electrode heating, the lamp circuit has lower power losses compared to rapid start ballast system. Although these lamps are rapid start, the lamp electrodes are never heated. This increases system

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efficacy. Lamp life is reduced by approximately 25% (for 20000-hour lamps at three hours per start), but this is compensated for by increased energy efficiency. In most commercial applications, where lamps are operated at ten hours per start or longer, lamp life is only slightly reduced in comparison to rapid start operation. These ballasts are available for either one or multiple lamps.

Although instant start systems are more efficient, lamp life will be

slightly less, so instant start mode ballasts should not be used where the lamp is frequently switched on and off. Likewise, using occupancy sensors with instant start lamp-ballast systems may cause an accelerated reduction of lamp life due to short cycle times. Rapid start lamp operation is usually a better choice in such applications.

(c) Rapid Start. In “rapid-start” circuits, cathodes are generally the

“low resistance” types and transformers are introduced to pre-heat the cathodes. Rapid start ballasts ignite lamps by providing cathode voltage (approximately 3.6 volts) and voltage across the lamp simultaneously (Figure 5.4). As the cathodes heat, the voltage required to ignite the lamp is reduced. At some time after both voltages are applied, the cathodes reach a temperature sufficient for the applied voltage to ignite the lamps. Rapid start ballasts heat lamp electrodes continually during starting and operation and the resultant watts loss remain part of the circuit while the lamp is operating.

During this starting scenario, voltage across the lamps creates a glow

current that damages the lamp by sputtering off the cathode’s emissive material. The sputtering results in end blackening and a reduction in lamp life. After all of this material is depleted from the cathode, the lamp ultimately fails.

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FILAMENT Voltage time (5V/div)

LAMP time

time

Voltage (500V/div)

LAMP Current

T1 T2

T3

Figure 5.4 Traditional Rapid Start

Ballasts are available for one, two, three, and four-lamp operation. Appendix G shows the different wiring diagrams for connecting lamp-ballast systems. 5.1.9 Other Types of Ballasts and Their Associated Starting Methods

(a) Programmed Start Ballast. Programmed start ballasts incorporate a precise starting scenario, which breaks the process into unique and well defined steps that eliminate the pitfalls of the other starting methods (Figure 5.4).

The first step in the series is the application of the cathode heat. While this heat is being applied (preheat interval), voltage across the lamp is reduced to a level that reduces damaging glow current. Glow current is actual lamp current that flows during this preheat interval and causes end blackening and degradation in lamp life. It is important during this step that sufficient voltage is applied to the cathodes for a long enough duration so that cathode’s temperature is at least 7000 C. The duration of this step is pre-programmed into the ballast circuitry. Since the lamp voltage is kept very low, the lamps cannot ignite until the cathodes are heated to optimal temperature and the ballast program moves to the second step.

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V

Figure 5.5 Programmed Start with Zero Glow Current Lamp Ballast Compatibility

Rapid starting does not guarantee that the cathodes are at their proper temperatures prior to lamp ignition. If applied voltage across the lamp is too high, the lamps will ignite before the cathodes are at their proper temperature. This will also cause sputtering of the emissive material. The programmed start ballasts’ combination of pre-heating time and voltage are set at a level to assure that the cathodes have reached the desired temperature before starting.

As mentioned earlier, glow current is the actual lamp current that flows across the cathode during a preheat interval and causes end blackening and degradation in lamp life. As the amount of glow current increases, the cathode emissive material also increases which is further detrimental to the lamp. The programmed start ballasts are able to keep sputtering to a minimum by reducing voltage across the lamp during the first phase. Some, but not all, programmed start ballasts have the capability to eliminate glow current completely by not applying any voltage across the lamps during the first step.

The second step of the starting process is the application of lamp voltage. After the programmed time of step one has been reached, a

FILAMENT oltage

(5V/div)

LAMP Voltage (500V/div)

time

time

time

T1 T2 T3

LAMP Current

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voltage is applied across the lamps, igniting them with minimal loss of the emissive material. Minimal loss of the emissive material equates to gentle treatment of and prolonged life for the lamp.

The time required for the lamp to move from the cathode heating stage to the full arc current stage is called the transition time. The longer this process is, the more emissive mix is being removed from the cathodes. Most rapid start ballasts have a transition time of about 80 to 100 milliseconds. The length of this transition is based upon the cathode’s temperature and the voltage across the lamp.

(b) Two-Level Electronic Ballasts. Two-level electronic ballasts

increase the flexibility of standard electronic ballasts by allowing the light level to be switched between 50% and 100% of full light output. Standard switches, occupant sensors, photocells, or other building energy systems may automatically operate these ballasts. Two-level Electronic Ballasts are supplied with an additional input lead to allow the switching between 50% and 100% operation.

(c) Adjustable Output (Dimming) Ballasts. Dimming electronic

ballasts permit the light output of the lamp to be continuously controlled over a range of approximately, 10% to 100% of full light output. A low voltage signal (usually between 0 and 10 volts) to the ballast output circuit modifies the current to the lamp. Dimming electronic ballasts are equipped with feedback circuits that maintain electrode voltage when the lamp current is reduced. This allows the lamp to be dimmed over a wide range without reducing lamp life. This dimming technique contrasts with that of electromagnetic ballasts in which the input power to the ballast is modified to alter the lamp current, which also reduces electrode voltage. These limit the practical dimming range of the lamp to about 50% of full light output.

(d) Full Range Dimming Ballasts. A full dimming range of from

1% to 100% of full light output may be achieved through the use of premium-priced electronic ballasts designed for this purpose. At present, these ballasts are only part of special control systems (see Chapter 7.6 for the discussion of DALI-Standard ballasts and control systems).

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5.1.10 Ballast Factor (BF) One of the most important ballast parameters for the lighting designer/lighting engineer is the ballast factor. The ballast factor is needed to determine the light output for a particular lamp-ballast system. Ballast factor is a measure of the actual lumen output for a specific lamp ballast system relative to the rated lumen output measured with reference ballast under ANSI test conditions (open air at 25oC). ANSI reference ballast for standard 40-watt F40T12 lamps requires a ballast factor of 0.95. However, many types of ballast are available with either high (conforming to the ANSI specifications) or low ballast factors (70% to 75%). It is important to note that the ballast factor value is not simply a characteristic of the ballast, but of the lamp-ballast system. Ballasts that can operate more than one type of lamp (e.g. the 40-watt F40 ballast can operate either 40-watt F40T12, or 40 watt F40T10 lamps) will generally have a different ballast factor for each combination. As F40T12 lamps are lately only sold for replacement purposes, nowadays a BF of 80 or less is preferred with T8 or T5 systems. Ballast Factor (BF) is calculated as follows:

BF = BF’ E1

E2

Where: BF = ballast factor of the test ballast BF’= ballast factor of the calibrated ballast

E1 = the illuminance reading on the testing rack of the test ballast/test lamp system

E2 = the illuminance rating on the testing rack of the calibrated ballast/test lamp system

Ballast factor is not a measure of energy efficiency. Although a lower ballast factor reduces lamp lumen output, it also consumes proportionally less input power. As such, careful selection of a lamp-ballast system with a specific ballast factor allows designers to better minimize energy use by "tuning" the lighting levels in the space. For example, in new construction, high ballast factors are generally best, since fewer luminaires will be required to meet the high level requirements. In retrofit applications or in areas with less critical visual tasks, such as

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aisles and hallways, lower ballast factor ballasts may be more appropriate. It is important to note that to avoid a drastic reduction in lamp life, low ballast factor ballasts (<70%) should operate lamps in rapid start mode only. This is particularly relevant for 36-watt F36T8 lamps operated at high frequency.

To use the graph, locate the curve (A-H) for the lamp-ballast system of interest. Draw a vertical line from the cited input power to that curve. Draw a horizontal line from that point to the vertical axis to find the ballast factor for that lamp-ballast system. It is essential that the input power cited by the manufacturer be measured under standard ANSI test conditions. *Note: This graph is applicable only for two-lamp 1.2 m systems; other lamp-ballast systems will defer

Figure 5.6 Power vs. Ballast Factor Curves for Two-Lamp 1.2 m Flourescent Lamp-Ballast Systems

Finding the ballast factor for lamp-ballast combinations may not be easy, as few ballast manufacturers provide this information in their catalogs. However, if the input power for a particular lamp-ballast system is known (usually found in catalogs) an estimate of the ballast factor is possible. Figure 5.5 provides a set of curves for determining the ballast factor for several two-lamp ballast systems. It is based upon the average system efficacy measured for ballasts at standard ANSI conditions.

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5.1.11 Energy Efficiency Fluorescent lamps are reasonably efficient at converting input power to light. Nevertheless, much of the power supplied into a fluorescent lamp-ballast system produces waste heat energy. There are three primary means of improving the efficacy of a fluorescent lamp-ballast system:

• Reduce the ballast losses. • Operate the lamp(s) at a high frequency, • Reduce losses attributable to the lamp electrodes.

Newer, more energy-efficient ballasts, both electromagnetic and electronic, exploit one or more of these techniques to improve lamp ballast system efficacy, measured in lumens per watt. The losses in electromagnetic ballasts have been reduced by substituting copper conductors for aluminum and by using higher-grade magnetic components. Ballast losses may also be reduced by using a single ballast to drive three or four lamps, instead of only one or two. Careful circuit design increases efficiency of electronic ballasts. In addition, electronic ballasts, which convert the 60 Hz supply frequency to high frequency, operate fluorescent lamps more efficiently than is possible at 60 Hz. Finally, in rapid start circuits, some electromagnetic ballasts improve efficacy by removing power to the lamp electrodes after starting. 5.1.12 Lamp-Ballast System Efficacy The efficiency of a fluorescent lamp ballast changes depending on the type of lamp operated. Similarly, lamp efficacy is affected by ballast technology: the same lamp will perform differently when operated by a heater cutout ballast than it will when operated at high frequency. As a consequence, the only meaningful comparison between lamps or ballasts is the lamp-ballast system efficacy. The system efficacy can be calculated as follows:

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System Efficacy (lumens / watt):

x Number of Lamps x Ballast Factor Rated Lamp Lumens Input Power (watts) = =

The above equation calculates initial system efficacy as measured under ANSI test conditions. 5.1.13 Reliability of Electronic Ballasts The reliability of electronic ballast has been questioned since their introduction in 1981. Some manufacturers' initial products failed prematurely. Those manufacturers who were unable to improve their products are no longer producing electronic ballasts. Other manufacturers have been in production over ten years with documented ballast failure rates of less than 1% after five years of operation. At this time, it is apparent that long-term usage has demonstrated the reliability of electronic ballasts. A main reason for the questioning of the reliability of electronic ballasts has been the lack of large scale, controlled, on-site data. However, in 1988, the University of California-Berkeley energy management group presented their findings on failures of electronic ballasts installed in a variety of campus buildings over a period of three and one-half years. Over 32,000 electronic ballasts were installed, supplied by three different manufacturers. (Source: R.S. Abesamis, etal., "Field Experience with High-Frequency Ballasts," Trans. IEEE-IAS, 26, #5, 8 10, Sept./Oct. 1990.) Two of the manufacturers' ballasts had failure rates of less than 1%—well within acceptable limits. The third manufacturer's ballasts had a 6% failure rate, and the company has since ceased manufacturing electronic ballasts. For comparison purposes, the general failure rate for 60 Hz electromagnetic ballasts is about 0.5%. The results of the University of California case study clearly demonstrate that electronic ballast technology has advanced enough so that efficient, reliable ballasts can be successfully designed and manufactured in large volume. Based on these findings, the university's ballast retrofit program was expanded, and a total of over 75,000 electronic ballasts have been installed at the campus, leading to considerable energy savings.

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The above case study suggests that reliable electronic high-frequency ballasts can be produced with the quality control necessary to reach or exceed the ten to twelve year life spans common with electromagnetic ballasts. Most ballast failure, when they do occur, will happen within the first six months of installation. Early ballast failures are usually due to either poor quality control in the manufacturing process or incorrect installation procedures. Failures occurring after a normal “wear-out” period of ten to twelve years are usually due to the eventual degradation of the electrolytic capacitor. Electronic ballast problems can be kept to a minimum if specifiers are diligent in their selection of ballast manufacturers. They should research the track records of manufacturers and obtain verification for the reliability of any new or unfamiliar products. 5.1.14 Ballast Noise Level (Sound Rating) All electromagnetic ballasts emit a hum that is caused by vibration of the laminated core of the ballast, vibration that results from the expanding and collapsing magnetic field in the core. High temperatures can increase noise, and it is amplified by certain luminaire designs. The best ballasts use high-quality materials and workmanship to reduce noise. Noise is rated A, B, C, or D in decreasing order of preference. An "A" rated ballast will hum softly; a "D" rated ballast will make a loud buzz. The number of ballasts, their sound rating, and the nature of ambient noise in the room determine whether or not a system will create an audible disturbance. Virtually all energy-efficient electromagnetic ballasts for F40T12 and F36T8 lamps are “A” rated, with a few exceptions, such as low-temperature ballasts. Still, the hum of electromagnetic ballasts may be perceptible in a particularly quiet environment such as a library. Well-designed electronic high frequency ballasts, on the other hand, should emit no perceptible hum. All electronic ballasts are "A" rated for sound.

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5.1.15 Dimming Most fluorescent lamps cannot be properly dimmed with a simple wallbox device such as those used for incandescent lamps. For a fluorescent lamp to be dimmed over a full range without a reduction in lamp life, its electrode heater voltages must be maintained while the lamp arc current is reduced. As such, lamps operated in rapid start mode are the only fluorescent lamps suitable for wide-range dimming applications. The power required to keep electrode voltage constant over all dimming conditions means that dimming ballasts will be less efficient when operating lamps at dimmed levels. Dimming ballasts are available in both electromagnetic and electronic versions, but there are distinct advantages to using electronic dimming ballasts. To dim lamps, electromagnetic dimming ballasts require control gear containing expensive high-power switching devices that condition the input power delivered to the ballasts. This is economically viable only when controlling large numbers of ballasts on the same branch circuit. In addition, luminaires must be controlled in large zones that are determined by the layout of the electrical distribution system. Since the distribution system is fixed early in the design process, control systems using electromagnetic dimming ballasts are inflexible and are unable to accommodate changes in usage patterns. Dimming of electronically ballasted lamps, on the other hand, is accomplished within the ballast itself. Electronic ballasts alter the output power to the lamps by a low-voltage signal into the output circuit. High-power switching devices to condition the input power are not required. This allows control of one or more ballasts independent of the electrical distribution system. With dimming electronic ballast systems, a low-voltage control network can be used to group ballasts together into arbitrarily sized control zones. This control network may be added during a building renovation or even, in some circumstances, during a lighting retrofit. Low-voltage wiring does not have to be run in conduit, which helps keep installation costs down. In addition, it is less costly to modify the size and extent of lighting zones by reconfiguring low-voltage wiring when usage patterns change. Low-voltage wiring is also

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compatible with photocells, occupancy sensors, and energy management system (EMS) inputs. Dimming range differs greatly among ballasts. With most electronic dimming ballasts, light levels can vary between full output and a minimum of about 10% of full output. However, electronic, full-range dimming ballasts are also available that operate lamps down to 1% of full lumen output. Electromagnetic dimming ballasts also offer many dimming options, including range dimming. 5.1.16 Flicker Electromagnetic ballasts are designed to condition the 60 Hz input voltage to the electrical requirements of the lamps. Electromagnetic ballast alters the voltage, but not the frequency. Thus, the lamp voltage crosses zero 120 times each second, resulting in 120 Hz light output oscillations. This results in about 30% flicker for standard halophosphor lamps, operated at 60 Hz. The flicker is generally not noticeable but there is evidence that flicker of this magnitude can cause adverse effects, such as eyestrain and headache. Most electronic ballasts, on the other hand, use high-frequency operation, which reduces lamp flicker to an essentially imperceptible level. The manufacturer usually specifies the flicker percentage of a particular ballast. For a given ballast, the percent flicker will be a function of lamp type and phosphor composition. 5.1.17 Harmonics When a current or voltage wave shape deviates from the ideal (sinusoidal), current or voltage harmonics are produced. Harmonic are sinusoidal voltages or currents that are higher multiples of the fundamental frequency. For example, the harmonics of 60 Hz are 60 Hz, 120 Hz, 180 Hz, etc., representing the first (fundamental), second, third, etc. multiples. Fluorescent ballasts affect the current, as opposed to the input voltage; in the process, current harmonics are generated. The amplitude of these harmonics is expressed as a percentage of fundamental.

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Recently electrical utilities have been concerned with the growing use of electrical equipment that generates harmonics. Such equipment may include variable speed drives, uninterruptable power supplies, personal computers, and electronic ballasts. Any circuit that is nonlinear (e.g. a gas discharge lamp) uses rectifying circuits, or uses high-speed switching systems will generate harmonics. If any one or combination of the above systems makes up a significant portion of a building's electrical load, the following undesirable effects may result:

• Overloading of transformers • Adding of current to the neutral in three-phase electrical

distribution systems • Current/voltage surges and/or spikes due to circuit resonances

with one or more of the harmonic frequencies • Interference with electrical equipment or communications on the

same circuit • Distortion of the electrical service entrance voltage with

accompanying adverse effects on the performance of other electrical equipment in the building

(a) Harmonic Distortion and Electronic Ballasts. When electronic

high-frequency ballasts were first introduced in the early 1980s, some models generated relatively high line harmonics. Nevertheless, at that time, harmonic currents produced by lighting equipment and other electronic systems were not, as yet, a utility issue. However, by the mid-1980s, utilities and power engineers were becoming increasingly more concerned about power equipment that generated line harmonics.

The harmonics issue first surfaced as a concern to the professional

lighting community when a major utility announced that electronic ballasts were required to leave total harmonic distortion (THD) of less than 20% of the fundamental, in order to qualify for their rebate program. Electronic ballast manufacturers responded to the utility's requirement by employing passive filtering that met the 20% limit at a slightly higher cost to the end user.

To help understand the issue, it is of interest to examine and compare

the harmonics generated by electromagnetic ballasts. The harmonics for some electromagnetic ballast exceed the 20% limit, and have been even

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measured at levels over 37%. This suggests that there are presently many electromagnetic ballasts in use that exceed the 20% THD limit. These ballasts have not been known to cause any problems with the electrical distribution where they are installed, further suggesting that the choice of a 20% limit on THD may be arbitrarily conservative. In any case, most electronic ballast manufacturers now make electronic ballasts that are well under the 20% limit.

(b) K-Factor and Harmonic Distortion. K-Factor is a metric used

for electrical transformer design that accounts for nonsinusoidal currents (i.e. currents that cause harmonics). These line currents generate higher eddy currents than a pure 60 Hz sinusoidal fundamental. Eddy currents cause transformers to operate at higher temperatures, increasing losses. To reduce the effect of eddy currents, transformer manufacturers use secondary windings consisting of well insulated, multiple wire strands. This increases the resistance of those windings, helping to limit the flow of eddy currents.

Until recently, engineers rarely specified K-factors for transformers.

However, it is recommended that electrical engineers designing lighting distribution systems calculate the K-Factor from the known harmonic distortion generated by the lamp-ballast system under consideration. This figure should be available from the ballast manufacturer. ANSI/IEEE 57.110-1986 is the recommended practice for establishing transformer capability for non-sinusoidal line currents, and it contains the equations for calculating K-Factor. Transformers with K-Factors of 1, 4, 9, 13, and 20 are standard products. Transformers with K-Factors of 4 or less are usually sufficient for lighting systems.

(c) Harmonic Distortion and Power Factor. Utilities are

concerned with low power factors because end users draw higher currents for the power that they are using. Ideally, lighting equipment should have a power factor greater than 0.9 and as close to 1.0 as possible. Power factors of less than 1.0 occur when the voltage and current are out of phase and/or when the sinusoidal wave shape is distorted. Harmonic currents generated by electronic ballasts reduce power factor due to a distorted current wave shape. (Harmonic currents produced by other types of electronic equipment can also lower the

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power factor by producing a phase shift between the voltage and current.)

Electronic ballast manufacturers now make a habit of publishing the

percentage of total harmonic distortion (THD) produced by their products. This allows a lighting professional to quantify how the installation of electronic ballasts in a building will affect power factor. Electrical distribution wiring may be sized accordingly. The relationship between power factor and total harmonic distortion with no voltage-current phase shift may be determined as follows:

Power Factor = 1 1+ THD2

As long as there is no voltage-current phase shift contribution to the power factor, THD may be as high as 48% and maintain a power factor of over 0.90.

(d) The IEC 61000-3-2:2005 Standards on Harmonics. The International Electrotechnical Commission based in Geneva, Switzerland developed the IEC 61000-3-2 in November 2005. The standard defines the limits on the magnitude of each harmonics depending in which class (A, B, C, D) the equipment falls in.

Class A: Balance three-phase equipment (r.m.s line currents

differing less than 20%) and all other equipment except that stated in one of the following classes.

Class B: Portable tools. Class C: Lighting equipment including dimming devices with

active input power above 25 W. Class D: Equipment having an input current with a “special

wave shape” and a fundamental active input power between 75 and 600 W. Whatever the wave shape of their input current. Class B, Class C, and provisionally motor-driven equipment are not considered as Class D equipment,

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The Limits for Class C Equipment1 are given below:

Class C > 25 W

Harmonic order Maximum value expressed n as a percentage of the fundamental input current of the luminaires

2 2 3 30λ* 5 10 7 7 9 5

11 <= n <= 39 3 λ* is power factor

Where λ* = power factor (W/VA) e.g. PF = 0.63 H(1) = 0.3055A Harmonic # 3 = 0.305A x [(30x0.63) + 100] = 57.6A Harmonic #29 = 0.305A x [3 + 100]

= 9.15mA

Reference: IEC 61000-3-2-Harmonic Limits 1Lighting Products are included in this category. (e) Third Harmonics of Current Electronic Ballasts. There are

electronic ballasts that have third harmonic levels below 20% and 10%. Harmonic levels of 20% are achieved by passive filtering devices, such as chokes, resistors, and capacitors. Active filters, such as integrated circuits and other semi-conductive devices, can reduce harmonics down to well under 10%.

While both electronic and electromagnetic fluorescent lamp ballasts

generate harmonics, one should understand that it is a systems problem. The potential for adverse effects in a given building primarily depends upon the size of the load imposed by harmonics-generating devices as a

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proportion of the total building load. The current harmonics (triplens) for fluorescent ballasts in three-phase distribution systems (e.g., branch circuits) are 120 degrees out of phase and will add on to the neutral wire.

(f) Other Harmonics Research. At the present time, data are being

collected to measure the voltage distortion at the service entrance of buildings that are lighted with electronically ballasted fluorescent lamps. Based on these studies, new standards may be developed that would require more stringent harmonic limits. The new limits would take into consideration the relative contribution of lighting to the total electrical load in relation to the expanded use of other equipment (personal computers, variable speed drives, microwave equipment, etc.) that also generate line harmonics. 5.1.18 New Generation of High Performance Electronic Ballasts Current technology development in the semiconductor field particularly in the Power MOSFET and ballast design have made it possible to operate at a wider input voltage range from 200 to 300 VAC safely. The Total Harmonic Distortion of less than 10% can be easily attained and power factor at above 99% are now common. Some manufacturers refer to this New Generation of High Performance Electronic ballast as Linear Electronic Ballast because of its power factor reaching near unity and suitable for a 208VAC, 230VAC, 265VAC or 277VAC power supply. The new generation of High Performance Electronic ballast normally employs a parallel-resonant configuration circuit that allows it to operate at a single or double lamp load.

5.2—APPLICATION GUIDELINES Advance technology for ballasts improve the efficacy of fluorescent lamp systems and are appropriate for both new construction and retrofit applications.

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5.2.1 Electronic Ballasts Electronic ballasts for fluorescent lamps can save energy and money in nearly every application. There is a cost premium for electronic ballasts, but prices are becoming more competitive as the market expands. Users like the University of California have demonstrated that electronic ballasts are an excellent institutional investment. Electronic ballasts may be substituted for electromagnetic ballasts without any need for concern about lighting system performance. In fact, electronic ballasts can enhance lighting quality through the added benefit of a quiet, flicker-free lighting environment. This makes electronic ballasts an ideal choice for modern offices and in other applications with important visual tasks.

5.2.2 Ballast Selection Considerations Use the following criteria when making ballast selections:

Always consider electronic ballast for general-purpose

applications in new construction. The higher cost of electronic ballasts makes economic sense in terms of energy savings and improved lighting performance over the life of the system.

Always consider electronic ballasts for routine maintenance replacements and renovations. (It may not be cost-effective to retrofit large groups of existing low loss electromagnetic ballasts in working order that would not otherwise be replaced.).

Consider operating F36T8 lamps at full output with instant start ballasts to obtain maximum energy efficiency for dedicated (non-dimming) applications with minimal on/off cycles.

Exercise caution to avoid using instant start lamp-ballast systems with occupant sensors or other applications with rapid switching cycles.

Consider stepped multi-level electronic ballasts as an excellent alternative to switching adjacent lamps in luminaires (tandem wiring). An additional benefit will be quiet, flicker-free space.

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Consider the use of low ballast factor (<75%) rapid start electronic ballasts in aisles or other circulation areas where partial light output will suffice. Installation of low ballast factor ballasts is also a cost-effective solution for retrofitting spaces that are illuminated. Low ballast factor electronic ballasts should be operated in rapid start mode only to maintain lamp life at reduced lamp currents.

Consider full-range (1%-100%) dimming electronic ballasts for functional dimming requirements in applications such as boardrooms, conference rooms, and residences.

Continuously adjustable dimming electronic ballasts are especially appropriate for all of the following lighting control strategies (see the appropriate guidelines for application details):

Tuning: the adjustment of illuminance levels according to user

needs Daylighting: the control of electric lighting levels in spaces

where natural light is present Lumen maintenance: the reduction of lighting power in

conventional systems that are designed to produce excess light when new to compensate for future light depreciation

Peak demand limiting (load shedding): the reduction of lighting power during the time of day when utility charges are at their highest levels

Adaptation compensation: adjusting interior lighting levels to more closely correspond-with exterior illumination

In most instances, electronic ballasts are manufactured in standard ballast housings. This allows for quick and easy replacement in existing luminaires and permits their use in already tooled new luminaires. To facilitate replacement, the wires on typical non-dimming electronic ballasts use the same color-coding as electromagnetic ballasts. Installation of electronic ballasts is actually easier than installing electromagnetic ballasts, because they weigh less. Most adjustable output and dimming ballasts have separate, low-voltage leads that permit a low-voltage, Class I signal to control lamp output. These ballasts are often designed to use in the luminaire so that Class II low-voltage wiring can

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be used within the building. Other dimming ballasts require no additional control wiring. 5.2.3 System Compatibility of Electronic Ballasts Like virtually all-lighting products, there are some applications in which high-frequency electronic ballasts may be incompatible with existing technologies. One of these instances that have been identified occurs in libraries equipped with magnetic detectors used to prevent theft. However, as long as electronic ballasts are at least 3 m to 4.5 m away from the detector units, problems with the detectors are unlikely to occur. A second potential system compatibility problem with electronic ballasts may occur in conjunction with high-frequency power line carrier (PLC) control systems. The carrier frequency for PLCs usually ranges from 50 kHz to 200 kHz. These frequencies may be affected by one of the harmonic currents generated by electronic ballasts. The extent of this potential problem has not as yet been fully researched. However, in simple PLC systems for residential applications when lighting and other appliances share the same distribution network, electronic ballasts may not be compatible. This may be resolved by the selection of a more appropriate frequency for the PLC system. In commercial systems where the PLC is isolated from the lighting circuits, problems may be minimal. If, however, the PLC is used to control the lighting system, the probability of problems occurring will increase. It is important to realize that the possible compatability problems posed by the use of electronic ballasts arise only on rare occasions. The above incompatibilities can be resolved or avoided, and they should not be used to disqualify the use of electronic ballasts in other applications. 5.2.4 Heater Cutout Ballasts Heater cutout ballasts are less expensive than electronic ballasts and are a viable energy-efficient option to consider when a project budget does not permit electronic ballasts. Heater cutout ballasts can be used in any non-dimming situation involving linear F32T8 or F36T8 lamps. Typical applications include offices, schools, retail and wholesale stores, health care facilities, and general industrial and commercial lighting. Because

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of their lower initial cost they are especially appropriate for use as replacement ballasts in retrofit applications. Some heater cutout ballasts may have a problem starting lamps when the line voltage is below its rated voltage. In addition, some lamp manufacturers derate lamp life when heater cutout ballasts operate lamps.

5.3—STANDARD FOR FLUORESCENT LAMP BALLASTS

Philippine National Standard (PNS) 2050-4: 2007 “Lamps and related equipment - Energy labeling requirements – Part 4: Ballast” prescribes the ballast efficacy factor (BEF) labeling requirements for electronic and electromagnetic ballasts. Manufacturers, suppliers and importers will be required to label the individual ballasts with the BEF rating.

DEPARTMENT OF

E N E R G Y P H I L I P P I N E S

XXBALLAST

EFFICACYFACTOR

Important: HIGHER BEF means HIGHER SAVINGS.

*bas

ed o

n st

anda

rd te

stco

nditi

ons

BEF* O5

12-3

4567

8

Figure 5.7 Ballast Energy Label

5.4—GUIDELINE SPECIFICATIONS

Specifying fluorescent lamp ballasts is not difficult. There are ways of ensuring that the preferred ballast requirements are clear to suppliers to avoid the substitution of inferior products. Furthermore, the designer should specify products that conforms with the following Philippine National Standards:

• PNS IEC 60921: 2006 (IEC published 2004) Ballast for tubular fluorescent lamps – Performance requirements

• PNS IEC 60929: 2006 (IEC published 2003) AC supplied electronic ballasts for tubular fluorescent lamps – Performance requirements

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• PNS IEC 60923: 2006 (IEC published 2005) Auxiliaries for lamps – Ballasts for discharge lamps (excluding tubular fluorescent lamps) - Performance requirement

• PNS IEC 61347-1: 2002 (IEC published 2000) • PNS IEC 61347-1: 2002 Amd. 1: 2006 (IEC published 2000

Amd.1: 2003) • PNS IEC 61347-2-8: 2002 (IEC published 2000) • PNS IEC 61347-2-3: 2002 (IEC published 2000) • PNS IEC 61347-2-3: 2002 Draft Amd. 1: 2006 (IEC published

2000 Amd.1: 2004) • PNS IEC 61347-2-9:2005 (IEC published 2000) • PNS IEC 61347-2-9: 2005 Draft Amd. 1: 2006 (IEC published

2000 Amd.1: 2003) • PNS 2050-4: 2007 Lamps and related equipment - Energy

labeling requirements – Part 4: Ballast

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Chapter 6. Lighting Systems and Luminaires

6.1—LIGHTING SYSTEMS A lighting system is defined as one or more luminaire with one or more lamps having a characteristic lighting distribution. Several types of luminaires with lamps can be combined to make up a lighting system. The lighting system itself and thus the choice of luminaires to make up the system depend on the use of the space to be illuminated and other more perhaps “artistic” concerns.

6.2—LUMINAIRES

6.2.1 Definition Luminaire is a lighting unit consisting of the following components: optical devices to distribute the light, sockets to position and protect the lamps and to connect the lamps to a supply of electric power, ballast of the lamp, if separate from the lamp, and the mechanical components required to support or attach the luminaire. 6.2.2 Functions of Luminaires. The main function of the luminaire therefore, is to efficiently direct light to appropriate locations without causing glare or discomfort. Ideally, a luminaire directs lamp output to where it is needed while shielding the lamp from the eyes at normal angles of view. Often, modern lamp technologies require special luminaire features in order to be used correctly. For example, T5 lamps are 58.3% smaller in diameter than equivalent T12 lamps, even while producing nearly as many lumens. Because T5 lamps are brighter per unit length than T12 lamps, proper luminaire shielding is more critical.

CHAPTER 6. LIGHTING SYSTEMS AND LUMINAIRES

Different luminaires may significantly affect the operating temperatures of lamps. This can have significant effects on the total performance of the luminaire-lamp-ballast system. For example, luminaires that cause fluorescent lamps to operate above their optimum operating temperatures will also cause reduced light output in those lamps. Similarly, electronic ballasts have high-frequency outputs that are subject to greater power losses in applications requiring extended wiring runs between the lamps and ballasts. It is also important to have a matched lamp-ballast combination that is not simply a combination that lights the lamps, but that is truly energy efficient, as well. In addition, luminaire photometry should be performed using the specific lamp-ballast system under consideration. Furthermore, conventional photometric calculations should be supplemented with correction factors that account for the application conditions 6.3—CLASSIFICATION Thousands of different luminaires are made by hundreds of manufacturers. Choosing luminaires that efficiently provide appropriate luminance patterns for the application is an important part of energy-efficient lighting design. Luminaire classification helps specifiers and manufacturers describe, catalog, and retrieve luminaire information. Luminaire can be classified according to source, mounting, construction, application, and/or photometric characteristics. 6.3.1 Classification by Photometric Characteristics

6.3.1.1 CIE Classification Luminaires are classified by the Commission Internationale de

L’Eclairage (CIE) according to the percentage of light output above and below the horizontal. The system is usually applied to indoor luminaires they are as follows:

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Direct Semi-Direct General Diffuse

0- 10%

Direct Lighting. When luminaires direct 90 to 100% of the their

output downward, they form a direct lighting system. The distribution may vary from widespread to highly concentrated, depending on the reflector material, finish and contour, and on the shielding or control media employed. Troffers and downlights are two forms of direct luminaires.

Direct lighting units can have the highest utilization of all types, but this utilization may be reduced in varying degrees by brightness-control media required to minimize direct glare. Veiling reflections may be excessive unless the distribution of light is designed to reduce the effect.

Reflected glare and shadows may be a problem with direct lighting

unless close spacing are employed.

100%

40-60%90- 40-60%

10-40%60-90%

90-100% 0-10%

40-60% 40-60%

60-90% 10-40%

Direct-Indirect Semi-Indirect Indirect

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Figure 6.1 Example of Direct Luminaire Luminous ceilings, louverall ceilings, and large-area modular

lighting elements are forms of direct lighting having characteristics similar to those of indirect lighting discussed in the paragraphs below.

Semi-direct Lighting. The distribution from semidirect units is

predominantly downward (60 to 90%) but with a small upward component to illuminate the ceiling and upper walls. The characteristics are essentially the same as for direct lighting except that the upward component will tend to soften shadows and improve room brightness relationships. Care should be exercised with close-to-ceiling mounting of some types to prevent overly bright ceilings directly above the luminaire. Utilization can approach, or even sometimes exceed, that of well-shielded direct units.

Figure 6.2 Example of Semi-direct Lighting

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General Diffuse Lighting. When downward and upward

components of light from luminaires are about equal (each 40 to 60% of total luminaire output) the system is classified as general diffuse. Direct-indirect is a special (non-CIE) category within this classification for luminaires that emit very little light at angles near the horizontal. Since this characteristic result in lower luminances in the direct-glaze zone, direct-indirect luminaires are usually more suitable than general-diffuse luminaires that distribute the light about equally in all directions.

Direct-Indirect Luminaire

Figure 6.3 Examples of General-Diffuse Luminaire General-diffuse units combine the characteristics of direct lighting described above and those of indirect lighting described below. Utilization is somewhat lower than for direct or semidirect units, but it is still quite good in rooms with high reflectance surfaces. Brightness relationships throughout the room are generally good and the upward

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light reflected from the ceiling softens shadows from the direct component. Pendant-mounted luminaires designed to provide a general-diffuse or direct-indirect distribution are frequently installed on or very close to the ceiling. Such mountings change the distribution to direct or semidirect since the ceiling acts as a top reflector redirecting the upward light back through the luminaire. Photometric data obtained with the luminaire equipped with top reflectors or installed on a simulated ceiling board should be employed to determine the luminaire characteristics for such application conditions.

Semi-Indirect Lighting. Lighting systems that emit 60 to 90% of

their output upward are defined as semi-indirect. The characteristics of semi-indirect lighting are similar to those of indirect systems discussed below except that the downward component usually produces a luminaire luminance that closely matches that of the ceiling. However, if the downward component becomes too great and is not properly controlled, direct or reflected glare may result.

Indirect Lighting. Lighting systems classified as indirect are those

which direct 90 to 100% of the light upward to the ceiling and upper sidewalls. In a well-designed installation the entire ceiling becomes the primary source of illumination, and shadows will be virtually eliminated. Also, since the luminaires direct very little light downward, both direct and reflected glare will be minimized if the installation is well planned. Luminaires whose luminance approximates that of the ceiling have some advantages in this respect. It is also important to suspend the luminaires a sufficient distance below the ceiling to obtain reasonable uniformity of ceiling luminance without excessive luminance immediately above the luminaires. Since the indirect lighting the ceiling and upper walls must reflect light to the work plane, it is essential that these surfaces have high reflectances. Care is needed to prevent overall ceiling luminance from becoming too high and thus glaring.

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Figure 6.4 Example of Indirect Luminaire

6.3.1.2 NEMA Classification System This system is based on the distribution of flux within the beam produced by the luminaire. It is used primarily for sports lighting and floodlighting luminaires.

Source: Adapted from the IESNA Lighting Handbook, 2000 9th Edition

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6.3.2 IEC Classification System International Electrotechnical Commission has classified Luminaires according to the type of protection against electric shock, the degree of protection against ingress of dust, solid objects and moistures, and the material of the supporting surfaces.

6.3.2.1 Protection Against Electrical Shock Luminaire shall be classified according to the type of protection

against electrical shock provided, as follows: Class 0 Luminaire – Luminaire in which a basic type insulation is

provided for protection against electric shock; this means that no device is provided for connecting accessible conductive parts that may be present to a protective conductor forming a part of the permanent electric installation. If the basic insulation should be damaged, protection is entrusted to the environment surrounding the fitting.

Class I Luminaire – Luminaire in this class are electrically

insulated and provided with a connection to earth. Exposed metal parts that could become live in the event of basic insulation failure are protected by earthing.

Class II Luminaire – - Class II Luminaire are designed and

constructed so that protection against electric shock does not rely on basic insulation only. This can be achieved by means of reinforced or double insulation. No provision for earthing is provided.

III Class III Luminaire – Protection against electric shock relies on

supply at Safety Extra Low Voltage (SELV) and in which voltages higher than those of SELV are not generated( max. 50V ac rms)

Luminaires with a rated voltage in excess of 250V shall not be

classified as Class 0. Luminaire shall have only a single classification. For example, for a luminaire with a built-in extra-low voltage transformer with provision for earthing, the luminaire shall be classified

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as Class 1 and part of the luminaire shall not be classified as Class III even though the lamp compartment is separated from the transformer compartment.

6.3.2.2 Protection Against Ingress of Dust and Moisture Luminaires shall be classified in accordance with the “IP” number

system of classification.

The designation to indicate the degree of protection consists of the characteristics letter IP followed by the numerals (the “characteristic numerals”) indicating conformity with the conditions stated on Table 6.1, which has the following format:

IP XY

Where:

IP (Ingress Protection) Code is a coding system to indicate the degree of protection provided by enclosure against access to hazardous parts, ingress of solid foreign objects, ingress of water and to give additional information in connection with such protection. X = Protection of persons against contact with or approach to live parts and against contact with moving parts (other than smooth rotating shaft and the like) inside the enclosure and protection of the equipment against ingress of solid foreign bodies. Y = Protection of the equipment inside the enclosure against harmful ingress of water.

Examples of common IP ratings of luminaires are shown in Table 6.2

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Table 6.1 Table 6.2 IP Rating TableSource: Adapted from the Lanzini Illuminazione Catalogo Professionale Edizione Intel 1997

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Table 6.2 Luminaires Common IP Ratings:

IP

RATING DESIGNATION APPLICATION

IP 20 Ordinary Luminaire Ballproof no protection from water ingress

Indoor Dry rooms without dust development

IP 44 Splash proof Moist rooms, open air locations

IP 54 Dust/ splash water protected

Dusty rooms, workshops subject to fire hazard.

IP 65 Dust/jet water protected Wet rooms, but with instense dust development

IP67 Dust and impermeable to presswater ( Immersible)

For underwater illumination (≤1m)

IP 68 Dust-proof/submersible Type

For underwater illumination (≥1m)

6.4—TECHNICAL DESCRIPTION 6.4.1 Luminaire Components. Luminaires generally consist of some or all of the following parts:

• Lamp holders or sockets of a particular light source • Light Control Components • Electrical Components • Mechanical Components

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Plug/Tail wire

Ballast

Lampholder

Lamp

Louver Assembly

Reflector

Spring

Reflector Clip

Housing

Figure 6.5 Basic Components of Luminaires

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An efficient luminaire optimizes the system performance of each of its components. Careful evaluation of photometric data often reveals the overall quality of a particular luminaire design. In evaluating a luminaire, its efficiency (the ratio of lumens emitted by the luminaire to lumens emitted by the luminaire’s lamps) and its distribution characteristics are of considerable importance. When assessing luminaire distribution, one should consider how the luminaire controls glare, as well as the proportion of lamp lumens that reach the workplane, as measured by the coefficient of utilization (CU). The CU also takes into consideration the effects of room configuration and surface reflectances. Light Sources. Efficient luminaires use the most efficient sources appropriate for that luminaire type. Luminaires should be selected specifically to take advantage of the unique features—particularly with respect to source size and thermal performance of each respective light source. Luminaires are commonly available for these lamps:

(a) Incandescent filament including tungsten halogen lamps (b) Low Intensity Discharge lamps, including linear fluorescent,

compact fluorescent, & induction (electrodeless) lamps (c) High Intensity Discharge Lamps

(1) Metal halide (2) High Pressure Sodium (3) Mercury

(d) Low Pressure Sodium lamps

Luminaires are less common for xenon arc and carbon arc lamps. 6.4.2 Light Control Components

(a) Reflectors. A Reflector is a device, usually of coated metal or

plastic, that is of high reflectance and is shaped to redirect the light emitted by the lamp.

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a) powder coated or specular aluminum reflector for strip fluorescent luminaire, (b)&(c) specular&grooved aluminum reflector for a compact downlight luminaire, (d) faceted reflector for a floodlight luminaire, and( reflector with”kicker” to direct light for wall-wash luminaire.

Figure 6.6 Examples of Reflectors

Advances in materials science have resulted in several key new materials capable of improving luminaire efficiency. These reflector materials have a mirror-like or a specular finish that permits precise redirection of incident light rays. These differ from standard painted reflectors that produce diffuse, scattered, or widespread distribution of the incident light. New reflector materials include the following:

• Anodized, specular aluminum, having a total reflectivity of 85-

90% • Anodized, specular aluminum, enhanced with a multiple thin-

film dielectric coating, having a total reflectivity of 88-94% • Vacuum-deposited, specular silver, applied on the front or rear

surface of a clear polyester film and adhered to a metal substrate, having a total reflectivity of 91-95%

Some efficient luminaires use the specular materials listed above in

carefully contoured reflectors for maximum control and efficiency. Another use of these materials is in specular "imaging" reflectors, designed as retrofit components to be inserted into existing luminaires. For example, in theory, an existing three or four lamp fluorescent troffer can have one or two lamps removed, and some of the lost light output can be recovered through the use of a "one-bounce" or specular reflector. The specular reflector replaces the troffer's original white-painted reflecting surface. By removing a lamp from a four-lamp troffer and

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inserting an optically superior specular reflector, it is possible to recover efficiency losses due to degradation of the original white paint and reduce the amount of light and heat trapped in the luminaires. This typically results in approximately the same light output from three lamps as from four without the reflector. When reflector replacement is combined with relamping of a luminaire's aging lamps and cleaning of the luminaire surfaces, light output may actually be greater than it was prior to the retrofit. In addition, by further improving lamp-ballast combinations, more dramatic delampings can be performed. However, use of reflectors with delamping will almost always change the original candlepower distribution pattern of the luminaire, which may or may not be desirable, depending on the application.

Sometimes, spaces are actually over-lighted to the extent that lamps

can be removed without adding a reflector and adequate illumination can be maintained. In these cases, reflectors may still be considered because, with a reflector, the luminaire lens is more uniformly bright, and the luminaire does not appear as if some of the lamps are missing.

Specular reflectors are also included in a number of new products.

However, the efficiency improvements are not as dramatic, when compared to the retrofitting of white-painted reflectors, because some of the advertised effectiveness of these reflector products is due to improvements over poorly shaped and/or deteriorated, painted reflector surfaces in old luminaires.

(b) Refractors. Refractors are light control devices that take

advantage of the change in direction that light undergoes as it passes through the boundary of materials of differing optical density (index of refraction), such as air to glass or air to plastic (see figure 6.7)

(c) DIFFUSERS – Diffusers are light control elements that scatter

(redirect) incident light in many directions. This scattering can take place in the material, such as in bulk diffusers like white plastic, or on the surface as in etched or sandblasted glass. Diffusers are used to spread light and, since scattering destroy optical images, obscure the interior of luminaires, suppress lamp images, and reduce high illuminance by increasing the area over which light leaves a luminaire. Examples of diffusers are shown in Fig. 6.8.

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a) Prismatic lens, b) spread lens, c) glass refractor, d) Fresnel refractor e) wrap around prismatic lens f) prismatic lens on troffer, g) drop lens, and h) spread lens refractor

Figure 6.7 Examples of Refractor

. a) and b) wrap-around diffuser, c) jelly jar diffuser, and (d) drop glass diffuser

Figure 6.8 Examples of Diffusers (d) Shades, Blades, Louvers, and Baffles. Shades and shields are

opaque or transluscent materials shaped to reduce or eliminate the direct view of the lamp from outside the luminaire (Figure 6.9) Blades, usually opaque and highly reflective, can be shaped and positioned to eliminate the direct view of the lamp from certain directions outside the luminaire and to control the direction from which the light leaves. If arranged in a rectangular grid, producing cells, they are called louvers. If arranged linearly they are called baffles. Louvers and baffles often are made of specularly reflecting metal, though some are of coated plastic.

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(a),(b) and (c) louvers for linear fluorescent, (d) cross baffles, (e) shield for industrial luminaire, and (f) hoods and cowls for track luminaires

Figure 6.9 Examples of Louvers & Baffles

6.4.3 Mechanical Components The mechanical components of a luminaire consist of a housing or general structure to support other components of the luminaire, and a mounting mechanism for the attachment of the luminaire to its support. If the luminaire uses a refractor or transparent cover, then hinged frames or doors often are provided to hold the lens. 6.4.4 Electrical Components The electrical components of the luminaire operate the lamp. The luminaire contains and supports ballast, starter, capacitors, or emergency lighting devices.

6.5—TYPES OF LUMINAIRE DESIGN AND CHARACTERISTICS

The most widely used luminaires are those designed for general illumination of large areas. In commercial lighting, these luminaires are usually fluorescent lighting systems designed to be mounted onto or recessed into a ceiling. These lighting systems consist of a luminaire layout pattern or "grid" that provides uniform lighting throughout the

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space. General lighting systems constitute the majority of lighting installations and the majority of the energy consumed for lighting. 6.5.1 General Lighting Luminaire Types. Among the thousands of lighting products on the market, there are a few that represent opportunities for energy conservation in lighting systems design. These are discussed below for general types of lighting systems.

6.5.1.1 Commercial and Residential Luminaire

(a) Open Direct Luminaires. Open direct systems do not employ shielding at all. These systems include surface and pendant-mounted strip fluorescent fixtures and suspended open industrial and commercial luminaires. Unless equipped with reflectors, these systems radiate light in all directions (see Figure 6.10). Open direct lighting systems are often very efficient, with high coefficient of utilization (CU) values, but they may cause visual discomfort and disability glare.

Figure 6.10 Open Direct Luminaire

(b) Imaging Specular Reflector Open Luminaires. The basic, open luminaire can be equipped with an imaging specular reflector. The imaging reflector may not improve luminaire efficiency, but the luminaire's coefficient of utilization (CU) can be increased as more light is redirected toward the work plane, as shown in Fig. 6.11.

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Figure 6.11 Open Luminaire w/ Specular Reflector

(c) Shielded Direct Lighting Systems. Shielded systems use some form of lens, louver, or baffle to prevent direct viewing of the lamps at normal angles of view (see Figure 6.12). Surface and suspended luminaire types include industrial HID downlights, baffled industrial fluorescent luminaires, fluorescent wraparound lens luminaires, and commercial fluorescent lens luminaires. Recessed systems include HID downlights and a wide range of fluorescent "troffers" using lenses, louvers, or baffles to control glare.

Figure 6.12 Shielded Direct Luminaire

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(d) Shielded Industrial and Commercial Luminaires with

Specular Imaging Reflectors. These luminaires are similar to open industrial and commercial luminaires. However, they are equipped with louver shielding. Specular imaging reflectors can increase luminaire efficiencies and coefficient of utilization. (See Fig. 6.13)

Figure 6.13 Shielded Industrial Luminaire

(e) Parabolic Louvered Recessed Troffers. An increasingly popular commercial general lighting fixture is the recessed parabolic troffer. There are large-cell and small-cell parabolic luminaires. Large cell luminaires are generally more efficient, with relatively high coefficient of utilization values, while smaller cells usually offer better glare control. The large-celled parabolic louvered troffer is a luminaire that can combine sharp cut-off glare control with an efficient reflector/louver design. Many different standard sizes are readily available, including 600mm x 1200mm, 600mm x 600mm, 300mm x 1200mm and others.

Three variations of large-cell parabolic luminaires are available:

• Standard parabolic troffers generally have louvers about 75

mm deep. Standard parabolics are efficient, and have good glare control and reasonably low brightness.

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• Deep-cell parabolic troffers have louvers that are a minimum of 100 mm deep. Deep-cell parabolics have moderate efficiency and CU values, very good glare control, and very low brightness shielding. Specular imaging reflectors can increase luminaire efficiencies and CUs.

• Compound parabolic troffers have specially designed parabolic louver assemblies to create extremely low brightness for Video Display Terminal (VDT) work environments. These fixtures have excellent glare control and will not produce reflected images in VDT screens if they comply with the luminance limits specified in the Illuminating Engineering Society's VDT Lighting: IES Recommended Practice for Lighting Offices containing Computer Visual Display Terminals (RP24-1989).

Specular and Semi-Specular Louvered Luminaires. These

luminaires are high-end parabolic fixtures containing shielding components made of anodized high-reflectivity aluminum. Semi-specular finishes, similar to stainless steel in appearance, are the most common type, as they tend to give the luminaire just enough brightness to appear "on." This brightness, however, may still be enough to be reflected in VDT screens, causing a loss in visual task visibility. Mirror-like specular finishes tend to decrease luminaire brightness. Compound parabolic troffers (see Fig. 6.14) generally use specular louvers, and they are intended for use in VDT environments.

Compound Parabolic Luminaires. Work areas having VDT

screens generally require very low brightness luminaires and ceilings to avoid veiling or reflected glare. Specially designed compound parabolic luminaires serve this requirement much more efficiently than do the small-cell parabolic cube louvers often used for this application, because less light is blocked by a smaller number of larger cells.

(f) Standard Lensed Troffers Equipped with Specular

Imaging Reflectors. The traditional lensed troffer (see Fig. 6.15) can be equipped with a specular imaging reflector. The efficiency of a two-lamp, 600mm x 1200mm, reflector-equipped luminaire consisting of a pattern-12 (standard) prismatic lens, and properly aligned lamps, rises from about 70% to about 80% with the addition of a specular imaging

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reflector. CU values increase, as well. The increase in efficiency and CU is greatest when the reflector is designed exactly for the luminaire and the desired light distribution. Most common lens types, such as prismatic, bat wing, linear batwing, and polarized, can be used, though not all types will exhibit increased efficiency when used with a reflector. Final photometric performance—especially uniformity of illumination, may be significantly altered, when compared to traditional painted troffers.

Figure 6.14 Typical Four-Lamp Parabolic Troffer

Figure 6.15 Example of Troffer with Prismatic Lens

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(g) Indirect Lighting Luminaires. Luminaires that radiate light

up to a reflecting ceiling are called indirect types (see Figure 6.16). Indirect lighting systems generally employ luminaires suspended from the ceiling, though cove lights and lights mounted to walls and furniture can also be used. Indirect lighting systems using well-designed and properly spaced luminaires can provide excellent illumination, uniformity, and freedom from glare. Their success depends on maintaining a high ceiling reflectance combination with nearly uniform brightness. In this way, a maximum amount of light is reflected down to the work plane, yet light patterns are less likely to create reflected glare in VDT screens. IES RP24 specifies the maximum to minimum ceiling luminance (brightness) ratio if reflections in VDT screens are to be avoided. Additionally, when using indirect lighting systems, it may also be necessary to install energy-efficient task lighting, as CU values may be low.

Recent designs in fluorescent indirect lighting systems use lenses

or imaging reflectors to achieve high luminaire efficiency, by producing a broad batwing light distribution while allowing for close-to-ceiling mounting. These designs can increase indirect system's CU to nearly that of traditional lensed troffer systems.

Figure 6.16 Indirect Lighting Luminaire

(h) Cove Lighting Systems. New designs in indirect lighting luminaires, especially for cove and coffer installations, increase the

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effectiveness of traditional strip lights and eliminate socket shadows. Figure 6.17 shows a typical distribution pattern.

Figure 6.17 Cove Lighting System

(i) Compact HID Indirect Lighting Systems. Compact HID

lamps allow for smaller uplight luminaires that are easily installed in furniture-mounted luminaires and wall sconces. (HID luminaires may not be suitable for applications when periodic switching is anticipated.) Figure 6.18 shows an example of HID Indirect Luminaire (Uplighter).

Figure 6.18 HID Indirect Luminaire (Uplighter)

(j) Direct/Indirect Lighting Systems. These systems combine the efficiency and high CU of direct illumination with the uniformity and glare control of indirect lighting (see Figure 6.19). Some industrial

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lighting systems are designed for a limited percentage of indirect uplight; some office and school lighting systems are designed for an equal balance between direct downlight and indirect uplight. Additionally, there are high-efficiency versions of direct/indirect lighting systems for commercial and institutional lighting, including some especially designed for VDT work environments. When used in VDT environments, these systems should meet the performance criteria of IES RP-24 with respect to both direct and indirect lighting.

Figure 6.19 Direct/Indirect Luminaire

(k) Stage. Stage luminaires are designed to produce tight optical control and provide maximum flexibility. They are commonly used in theaters and television studios for lighting stage and people.

Figure 6.20 Examples of Stage/Theater Luminaires (a) Fresnel spot, (b) ellipsoidal spot, and(c) border spot.

6.5.1.2 Architectural Luminaires. Architectural lighting is generally employed in building spaces such as lobbies, corridors and the like. Typical lighting types include recessed downlights, wall washers, track lights, and some wall sconces. Since these luminaires are used

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initially for highlighting high-quality spaces, aesthetics is a principal consideration in their design and selection. Nevertheless, there are many opportunities to utilize efficient lighting in these applications.

(a) Recessed Low-Wattage HID Downlights. HID downlights suitable for lower ceilings and high-quality spaces have been made viable with high-CRI compact metal halide and white high-pressure sodium lamps. This allows for replacement of traditional incandescent downlights, making significant energy savings possible. Examples of Low Wattage HID downlights are shown in Figure 6.21 below.

Figure 6.21 Examples of Low Wattage HID Downlights (b) Recessed Compact Fluorescent Downlights. The popular

compact fluorescent downlight is now available in a variety of configurations, including dimmable lamps designed for use with electronic ballasts. In general, compact fluorescent lamps replace incandescent downlights on a 1 watt for 3-watt basis. By using parabolic downlight for compact fluorescent lamps it can improve efficiency by allowing replacement of incandescent lamps on a 1 watt for every 4-watts basis. An example of recessed architectural CFL downlight is shown in Figure 6.22

(c) Track-Mounted HID and Compact Fluorescent Floodlights. Tracklights use a system that includes luminaires and a track or rail that is designed to both provide mounting and deliver electric power. Several interesting designs in track luminaires using compact fluorescent and low-wattage HID lamps have been introduced. These products offer significant energy savings over standard

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incandescent luminaires of this type. Figure 6.23 illustrates an example of a compact fluorescent track light and floodlights

Figure 6.22 Example of Recessed Architectural CFL Downlight

a b)

Figure 6.23 a) HID Tracklight, b) Compact Fluorescent Floodlight

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(d) Compact Fluorescent Adapters with Screw in Power Connections. Techniques are available for retrofitting incandescent downlights with compact fluorescent technology. Except for the means of connecting power, these designs have elements used in conventional luminaires: a lamp holder with replaceable lamp and a housing for the ballast and other components. Some designs make use of the incandescent lamp holder's medium-base screw-shell for mounting and power connection. Some designs are also equipped with reflectors and/or lenses to improve light distribution and provide shielding (see Figure 6.24). The reflector and lens assembly is designed to correctly match the lamp for optimum performance. Also, the lamp can be replaced without replacing the rest of the assembly, reducing the chance that an incandescent lamp will be substituted at a later time.

Key items in the specification should include the lamp operating

current, lamp compartment temperature, and the lamp base temperature. In general, these types of luminaires cannot be used with dimmers.

Figure 6.24 Screw-in Compact Fluorescent Luminaire 6.5.1.3 Task Lights. Task-ambient lighting designs generally utilize

two separate lighting systems to improve lighting while saving energy. First, an ambient lighting design provides a medium-to-low level of uniform illumination in a room. Most general lighting systems can be used for ambient lighting. Second, task lighting is provided at and for

166


specific visual tasks. Compact fluorescent lamp technology has special relevance for task lighting applications. In VDT applications where high levels of ambient light often interfere with visibility, task lighting (Fig. 6.25) may be especially important for non-VDT tasks, particularly when those visual tasks are difficult to perform because of low contrast, high speed, and/or worker age.

Figure 6.25 Typical Compact Fluorescent Task Light 6.5.1.4 Decorative Luminaires. A renaissance in decorative lighting

fixtures in the form of pendants, wall sconces, chandeliers, exterior lanterns, and landscaping lights were introduced in the 1980s. In most instances, decorative lighting luminaires are used to provide general or ambient lighting in areas where a more customized appearance is desired. Although decorative lighting is still most often used in restaurants and hotels, an increasing number of applications exist in offices, retail stores, apartment buildings, and other commercial spaces. Energy-conserving decorative luminaires utilizing advanced lighting technologies have increased options for lighting efficiency.

(a) Low-Wattage HID and Compact Fluorescent Wall-Mounted Luminaires. Many traditional applications for incandescent wall-mounted sconces and brackets can be replaced with similar-appearing luminaires designed specifically for compact fluorescent or HID lamps. See Figure 6.26 for an example.

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Figure 6.26 Compact Fluorescent Wall Sconces

(b) Compact Fluorescent Pendants and Chandeliers.

Luminaire designs continue to evolve for compact fluorescent decorative chandeliers and pendants used in applications once limited to traditional incandescent fixtures. See Figure 6.27 for an example.

Figure 6.27 Decorative Pendant Luminaires

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(c) Compact Fluorescent Exterior Luminaires. Compact fluorescent lamps can be used in enclosed luminaires for exterior lighting. In colder climates, electronically ballasted compact fluorescent lamps may be required to ensure proper operation at lower temperatures. Compact fluorescent outdoor luminaires (Fig. 6.28) are especially well suited for landscape lighting applications, which previously used low-wattage incandescent lamps.

Figure 6.28 Examples of Compact Fluorescent Exterior Luminaires

(d) Low-Wattage HID Exterior Luminaires. While larger HID

lamps are commonly used as exterior light sources, low-wattage (100 watts or less) HID lamps offer the opportunity to use these lamps for more compact luminaires. In many cases, low-wattage HID luminaires can be used where incandescent lamps are typically chosen.

Low-wattage HID lamps can be used in every climate region

because of their wide temperature range for starting and operating. The small lamp size makes them suitable for many outdoor luminaires.

6.5.1.5 Emergency and Exit. Emergency lighting luminaires (Fig. 6.29) are designed to provide enough light for egress in emergency situations. They may operate from power provided by batteries. Under normal condition the batteries are continuously charged from line voltage. These luminaires contain circuitry that turns them on whenever line voltage is not present.

Exit luminaires help building occupants identify directions to an exit.

They are of illuminated signage, which are designed to provide critical

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help in emergency situations. Compact fluorescent lamps and LEDs are commonly used in exit luminaires.

Figure 6.29 Examples of Emergency & Exit Lights 6.5.1.6 Industrial Luminaires

(a) Linear Fluorescent. These luminaires are often designed for

high-output fluorescent lamps, with the reflector often being part of the housing. These luminaires are designed to minimize accumulation of dirt by providing for convection; in areas with large amounts of airborne particles, dust tight covers are used. Diffusers with gasketting are often used in wet locations. Examples of linear fluorescent luminaires for industrial application are shown in Figure 6.30 below.

Figure 6.30 Examples of Linear Fluorescent Luminaires for Industrial Application

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(b) Strips/Batten. These luminaires have one or more

fluorescent lamps and mounted to a small housing large enough to hold ballasts and sockets. Reflectors are uncommon since these luminaires are used in areas where a large amount of general diffuse lighting is required and efficiency and budget are a concern. Examples of strip or batten luminaires are shown in Figure 6.31 below.

Figure 6.31 Examples of Strip or Batten Luminaires

(c) High Bay. These luminaires use HID lamps to produce general lighting in an industrial area. They are for application of with spacing-to-mounting height ratios of up to 1.0. They are surface or pendant mounted, depending on the structure and openness of the area. These luminaires use reflectors and refractors to produce luminous intensity distributions that vary from narrow to wide, depending on the application and the need for vertical illuminance. Examples of high bay luminaires are shown in Figure 6.32 below.

Figure 6.32 Examples of High Bay Luminaires

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(d) Low Bay. These luminaires used HID lamps to produce

general lighting in an industrial area. They are for applications with space-to-mounting height ratios greater than 1.0. As with high bay luminaires, they are surface or pendant mounted. These luminaires usually have wide luminous intensity distributions to provide greater horizontal and vertical illuminances in areas with restricted ceiling heights. Examples of low bay luminaires are shown in Figure 6.33 below.

Figure 6.33 Examples of Low Bay Luminaires

6.5.1.7 Outdoor Luminaires

(a) Floodlight. These luminaires are often used for building lighting and other special application such as billboard lighting. Most types of HID lamps are used in floodlight luminaires. Lamp orientation and reflector arrangement normally determine beam characteristics. Depending on the portion of the building being illuminated and its distance from the luminaire mounting location, exterior building lighting use luminaires with narrow and wide distributions. Column lighting, accent lighting and distance mounting locations require narrow distributions. Lighting large areas with near mounting locations requires very wide distributions. Examples of floodlights are shown in Figure 6.34 below.

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Figure 6.34 Examples of Floodlights

(b) Sports Lighting. Some sports lighting luminaires (Fig. 6.35)

have very narrow luminous intensity distributions and typically mounted to the side and well above the playing area. High wattage metal halide lamps are common for sports lighting luminaires from 1000W-3500W. Reflectors are used to produce the required luminous intensity distributions. Since aiming is a critical part of their application, these luminaires are usually provided with special aiming and locking gear (goniometer). Internal or external louvers also may be provided to control glare and light trespass and to improve observer comfort.

Figure 6.35 Examples of Sports Lights

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(c) Street and Roadway. These luminaires are designed to produce reasonably uniform illuminance on streets and roadways. They are usually mounted on arms of a pole, or are post-top mounted. All types of HID lamps are used in these luminaires but commonly they use High Pressure Sodium Lamps for roadway applications. Some streetlights commonly use metal halide or mercury lamps. Luminaires with drop dish or ovate refractors are commonly used in roadway applications. Because of their appearance these luminaires are referred to as “cobra head” luminaires. (See Fig. 6.36).

Figure 6.36 Examples of Street and Roadway Luminaires

(d) Pathway. Walkway and grounds lighting is often accomplished with bollards. These luminaires are mounted in the ground and have the form of a short thick post similar to that found on a ship or wharf (see Fig. 6.37). They are used for localized lighting. Their size is appropriate for the architectural scale of walkways and other pedestrian areas.

Small sharp cut-off luminaires are also used on small poles to

provide pathway lighting. Luminaires for lighting outdoor stairs and ramps are used. These can be mounted on poles or recessed into the structure near the stair or ramp.

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Figure 6.37 Example of Pathway Luminaire

(e) Parking Lot and Garage. Parking lot lighting often uses

cut-off or semi-cut-off luminaires with flat-bottomed lenses. These luminaires are mounted on post-top brackets or on short arms and can be arranged in single, twin, or quad configurations. Wall mounted luminaires are often used for small parking lots immediately adjacent to a building or in parking structures, often referred to as “wall packs” wall-mounted luminaires.

Surface mounted luminaires in parking structures are mounted

on walls or ceilings. These are designed to produce a considerable amount of interreflected light in the structure. (See Fig. 6.38)

Figure 6.38 Examples of Garage and Parking Lot Luminaires

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(f) Security. Security luminaires (see Fig 6.39) are typically outdoor luminaires designed to help visually secure an area. This can mean providing sufficient illuminance for visual surveillance or security camera surveillance. These luminaires are typically mounted in inaccessible places and have particularly strong housings and lenses to help them become less susceptible to vandalism.

Figure 6.39 Examples of Security Luminaires

(g) Landscape. Landscape luminaires (see Fig. 6.40) are designed for outdoor use to light buildings, plants, water features, and walkways. They can be mounted on the ground, poles, trees, or underwater. Typically they have special housing, gasketting, lenses, and electrical wiring hardware that protects against the effects of water and corrosion.

Figure 6.40 Examples of Landscape Luminaires (a) ground and path luminaire, (b) and (c) direct burial and well-mounted landscape

luminaires, (d) bollards for lighting pathways

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6.5.1.8 Luminaire Design Considerations a) For T5 Lamps. Although the ambient temperature surrounding T5 lamps has a great impact on the lumen output, there is another factor, which is of great importance – the cold spot. Unlike T8 lamps, where the cold spot is located in the middle of the lamp, with T5 lamps, the cold spot is located at one end of the lamp as shown in Fig. 6.41 below.

Lamp stamping

2 mm between the glass and the measuring point on the G5 cap

FH28W/840

Measuring point with the best correlation to the cold-spot temperature

x

Figure 6.41 Measurement of the ‘cold spot’ Temperature for T5 Lamps

In designing the luminaire, heat dissipation should be such that the temperature at the ‘cold spot’ remains around 50oC. Any variation greater than 5oC to 7oC either way, will reduce the lumen output by 5%. This percentage increases with the variance.

It should also be noted that variations in lamp voltage is also

related to luminous flux. A 5% drop in lamp volts will translate into

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around 20% drop in relative light output, and a 15oC drop in cold spot temperature.

The slimmer diameter of T5 lamps allows more compact

luminaire designs. Thus suspended up/downlighters become more aesthetically pleasing and compact solutions for special applications can be realized.

When using louvered or open luminaires, glare control should be

given more attention because the T5 lamps have luminance levels nearly twice as high as T12 lamps. Table 6.3 below shows typical readings for various lamp types.

T2 T5 T5 Circular

T12 T8

7

6

5

4

3

2

1

0

0.86 0.6

1.1 1.2 1.5 1.72.5 2.8 2.9 3.2

1.72.1

2.6 2.63.0 2.8

3.9

7.0

3.6

Lum

inan

ce c

d/cm

2

L 40

W/2

5

FQ 3

9W/8

40FQ

54W

/840

FC 4

0W/8

40FC

55W

/840

DS

11W

/840

DD

18W

/840

DL

36W

/840

DL

55W

/840

DT/

E 57

W/8

40

Table 6.3 Comparative Luminance of Fluorescent Lamps

Compact Fluorescent

L 36

W/2

5L

58W

/25

L 36

W/2

1-84

0L

58W

/21-

840

FH 1

4-35

W/8

40FQ

24W

/840

FQ 8

0W/8

40FM

6-1

3W/8

40FC

22W

/840

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FH lamps are quite unique, in respect to their luminance, which

is the same (1.7cd/cm2) for each wattage (14W, 21W, 28W, 35W). This feature makes T5 FH lamps particularly suited for use in cove lighting systems. Since there is no difference in luminance, the lamps, regardless of their wattage, the illuminance on the ceiling will appear the same. With T8 lamps, when lamps of different wattages are combined to fill the length of a lighting cove, the appearance varies since the luminance of the lamps varies with the lamp wattage, i.e. it is clearly visible where the 36W and 18W lamps are located.

b) Other Technology Design Considerations Table 6.4 below shows the design considerations for other technologies:

Table 6.4 Technology Design Considerations Option Replaces Why More Efficient?

Shielded Direct Lighting Systems Parabolic large-cell louvered recessed and surface troffers

Low brightness “CRT”-type parabolic luminaires

Standard lensed troffers equipped with imaging reflectors

Shielded industrial/commercial fixtures with imaging reflector

Lensed painted troffers

Small-cell parabolic cube louvered luminaires

Standard lensed troffers

Painted reflector luminaires

Increase in luminaire efficiency and effectiveness; improved glare control

Increase in luminaire efficiency and effectiveness; no loss of glare control; no apparent ceiling darkness

Increase in luminaire efficiency, generally with an increase in coefficient of utilization

Imaging reflectors can increase luminaire efficiency by concentrating light downwards and can increase overall lighting effectiveness

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Table 6.4 (continued) Option Replaces Why More Efficient?

Indirect Lighting System High-efficiency and low-ceiling fluorescent indirect systems

Cove lighting systems

Compact HID lighting systems

Conventional up lights

Staggered Fluorescent Strips

Incandescent and halogen luminaires

Increased luminaire efficiency; wider spread in luminaires designed to be used in computer CRT spaces

Increase in cove efficiency combined with improved installation due to luminaire butt-joint without socket shadow better spread across ceiling due to asymmetry

Allows use of high-efficacy HID lamps in up lights, previous available only for low-efficacy incandescent and halogen luminaires

Direct/Indirect Lighting Systems High-efficiency direct/indirect lighting system

Conventional direct/indirect Luminaires

Improved cutoff for use in computer work is combined with efficient optical systems to provide greater efficiency and acceptability in modern office applications

Open Direct Lighting Systems Imaging specular reflector open luminaires

Painted open luminaires Imaging reflectors can concentrate light downwards increasing overall lighting system effectiveness

Architectural Luminaires Recessed compact fluorescent downlights

Incandescent downlights

Direct replacement in many situations with approximate wattage reduction of 67% at same illumination level and aesthetic effect. Especially useful in low-to-medium height ceilings.

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Table 6.4 (continued) Option Replaces Why More Efficient?

Architectural Luminaires Recessed low wattage HID downlights

Track-mounted HID and compact fluorescent floodlights

Compact fluorescent task lights

Low wattage HID and compact fluorescent wall lights

Compact fluorescent pendants & chandeliers

Incandescent downlights

Incandescent and halogen wall washers

Incandescent and halogen task lights

Incandescent and halogen wall lights

Incandescent and halogen luminaires

Direct replacement in many situations with approximate wattage reduction of 50-67% at same illumination level and aesthetic effect. Useful at most ceiling heights

Direct replacement in many situations with approximate wattage reduction of 50-67% at same illumination level and aesthetic effect. Useful at most ceiling heights

Significant wattage reduction



6.6—PHOTOMETRIC DATA FOR LUMINAIRES

"Photo" means light; “metric” means measurement. Photometry involves the measurement of the light radiated by luminaires. Photometric charts, diagrams and other data are used in all types of lighting calculations and design. The introduction of new technologies makes it difficult for the lighting industry to provide consistent photometric data because of the number of different combinations of luminaire components; each combination has a different effect on luminaire-lamp-ballast system performance. Additionally, product designs to be operated in conjunction with older technologies, such as F40T12 fluorescent lamps and electromagnetic ballasts, will behave differently and will require different measurements,

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when operated in conjunction with a newer technology, such as T8 lamps and electronic ballasts. Thus, the designer must consider the entire luminaire-lamp-ballast system and application when selecting the correct photometric data.

Figure 6.42 Polar Intensity Diagram The polar intensity diagram (see Fig. 6.42) provides a rough idea of the shape of the light distribution of a luminaire. In the polar intensity diagram, the luminous intensity is given in the form of a polar diagram. The luminous intensity is given in candela per 1000 lumen (cd/1000lm) of the nominal lamp flux of the lamps applied. The diagram gives the light distribution in two planes:

(a) Dotted Line. In the vertical plane through the length axis of the luminaire, the so-called C90-C270 plane is indicated as in Fig. 6.42(a):

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Figure 6.42(a) Dotted Line

(b) Continuous Line. In the vertical plane through the width axis of the luminaire, the so-called C0-C180 plane is indicated as in Fig 6.42(b) below:

Figure 6.42(b) Continuous Line

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If the light distribution of a luminaire is rotational-symmetrical, like downlights, spotlights, and industrial high-bay luminaires, the light distribution in only one C-plane is given. Note that for asymmetrical light distributions two planes are not sufficient for calculation purposes. Yet in the polar intensity diagram, only two planes will be given and this is universally accepted. 6.6.1 Light Loss Factors. In today's era of evolving technologies, the designer must account for a variety of light loss factors (LLFs) that must be used in conjunction with photometric data provided by manufacturers and testing laboratories. It is important to consider all factors that affect lighting system performance and to account for the influence of these individual factors as accurately as conditions permit. If these factors are not carefully considered, the designer may be tempted to use a very large LLF as a safety margin. This leads to inefficient designs that are wasteful, consuming more power than designs with well-conceived light loss factors. There are two types of LLFs: nonrecoverable and recoverable. (See Chapter 8 for a complete discussion.) Lamp lumen depreciation (LLD) from aging and dirt accumulation on lamps, reflectors, lenses, and room surfaces are the principal recoverable light loss factors. Since lumen output depreciates with aging, most lighting designs base calculations on “maintained,” as opposed to “initial,” lamp lumens. Many fluorescent lamps that use phosphors (such as halophosphor "cool white), depreciate significantly over lamp life. On the other hand, newer technology “triphosphor” lamps depreciate significantly less over the same period of time, as compared to conventional halophosphor lamps. This results in different LLD values. 6.6.2 Overall Light Loss Factor. The thermal factor (see the next section and Chapter 8), dirt depreciation factors, and lamp lumen depreciation can be significant. Accurate design calculations must consider these and other variables. As an example, if photometric data is given for standard F40T12 cool white lamps and electromagnetic ballasts, but the luminaire is to be equipped with F36T8 triphosphor lamps and an electronic ballast, the following adjustments should be considered:

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• Change in initial lamp lumens, due to the different lamp type. • Change in ballast factor, due to the electronic ballast • Increase in application thermal factor, due to the electronic

ballasts. • Probable increase in the LLD multiplier, because of the

triphosphor coatings in the T8 lamp (Note: an increase in LLD actually means that lamp lumen depreciation is less)

• Possible increase in luminaire efficiency due to the smaller diameter of the T8 lamp.

The end result of using the T8 lamps and electronic ballasts as described above would be a reduction of energy use of more than 20% with no significant change in lighting level. This would more than offset the higher cost of this lamp-ballast combination. When LLFs are considered, electronic ballasts produce even more dramatic energy savings and should be considered in almost every possible lighting application.

6.7—LIGHTING SYSTEM PERFORMANCE The lighting system consists of the luminaire itself along with the reflectors, lenses and housings, as well as the lamps and ballasts. System performance depends on how well all these components work together. With the introduction of many new products—especially electronic ballast – designers must pay special attention to the interactions between lamps, ballasts, and luminaires. Thermal effects, in particular, vary widely and affect luminaire-lamp-ballast system performance. With fluorescent lamp-ballast systems, light output (lumens), input watts, and efficacy are all sensitive to changes in the ambient temperature. When the ambient temperature around the lamps is significantly above or below 25oC, the performance of the lamp ballast system can change significantly. Figure 6.43 shows this relationship for two common lamp-ballast systems: (a) the F40T12 lamp with magnetic ballast and (b) the F36T8 lamp with electronic ballast. Figure 6.43 shows that the optimum operating temperature for the F36T8 lamp-ballast system is higher than the F40T12 system. This means that for installations when the lamp ambient temperature is greater than 25oC, the performance of the F36T8 system is actually higher than

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performance under the applicable PNS conditions. Performance of lamps with even smaller diameters, such as T5 twin tube lamps, peaks at even higher ambient temperatures. For example, the FT28T5 lamp peaks in lumen output when the ambient temperature approaches 32oC.

(a) F40T12 Lamp with Magnetic Ballast

(b) F36T8 with Electronic Ballast

Figure 6.43 Sensitivity of Lamp-Ballast Performance to

Ambient Temperature

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While the information in the Polar Intensity Diagram (Fig. 6.42) is interesting, it does not provide much information to the designer faced with the responsibility of designing an energy-efficient lighting system that provides specified design illuminance levels. Data like that shown in Fig. 6.43 should be combined with luminaire performance data from the manufacturers’ catalog. 6.7.1 Typical Luminaire Installations. Typical luminaires used locally are the following:

Parabolic troffer type, recessed mounted Same as above but with air vents for HVAC return air Surface mounted, “vandal resistant”, dust tight

6.7.2 Recommended Spacing for General Office Lighting Applications. When more than one luminaire is required in an area, the general procedure shown in Fig. 6.44 should be followed. Uniform light distribution is achieved by spacing the luminaires so that the distances between the luminaires and walls follow these recommended spacing guides. The spacing ratios for specific luminaires are given in the data sheets published by each manufacturer. This number, usually between 0.5 and 1.5, when multiplied by the mounting height, gives the maximum distance that the luminaires may be separated and provide uniform illuminance on the work surface.

6.7.3 Recommended Spacing for Other Applications. Uniform lighting requires that the spacing between adjacent luminaires must not exceed defined limits (refer to Figure 6.45). The diagram on the left shows a spacing arrangement that does not give uniform lighting. The diagram on the right shows that with reduced spacing, the lighting levels are reasonably uniform.

Spacing limitations between luminaires are a function of their intensity distribution patterns and their mounting heights. The luminaire spacing criterion (SC) is a classification relating to its distribution pattern. This classification is done numerically.

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Figure 6.44 Recommended Spacing

500 lx

6m

400 lx

3m 3m

500 lx 500 lx100 lx 400 lx 500 lx 500 lx

Figure 6.45 Spacing Requirements for Reasonably Uniform Lighting

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For luminaires using essentially point sources of light, such as CFLs or HID lamps, the maximum spacing applies equally to both directions in the room. Luminaires using fluorescent lamps, because of their length, do not necessarily fit this pattern. A very common and desirable arrangement is continuous rows of fluorescent luminaires in one direction in the room, usually lengthwise, as shown in Figure 6.46(a). The maximum spacing then applies only between the centerlines of each row. Where rows of fluorescent luminaires are not continuous, the maximum spacing along the rows applies as shown in Figure 6.46(b). For 1.2 m long luminaires, the maximum spacing is from centerline to center line (the same as for point sources). These guidelines are based on the fact that the distribution of light from the ends of fluorescent luminaires is not as good as it is from the sides.

Figure 6.46 Maximum Spacing Dimensions for Fluorescent

Luminaires

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In many lighting layouts, the final spacing is less than the maximum permitted by the spacing criterion. After the theoretical number of luminaires required for the layout has been calculated, it is necessary to adjust this number so that it can be evenly divisible by the number of rows. For point sources of light, the ratio between the number of rows and the number of luminaires per row should be in proportion to the width-to-length ratio of the room. This is required to give symmetrical spacing in both directions in the room for uniform lighting [refer to Figure 6.47(a)]. The exact spacing between rows is calculated by dividing the room width by the number of rows. Spacing between luminaires in each row is calculated by dividing the room length by the number of luminaires per row. This means that the spacing between the outer luminaires and the adjacent wall is one-half of the luminaire spacing. If it is known that desks or other work areas are to be located alongside the walls, then the wall-to-luminaires spacing should be reduced to one-third of the luminaire spacing. For fluorescent luminaires, it is often necessary to first establish the maximum number that can be installed in one row. Refer to Fig. 6.47(b). It is necessary to allow some space between the ends of the rows and the walls. Therefore, the maximum number is calculated by subtracting at least 0.3 meter from the room length and then dividing by the length of the luminaire. The spacing between rows of fluorescent luminaires is determined the same as previously indicated for rows of point sources. The final layout of luminaires in practice is very often influenced by the building structural details. Such things as the location of beams and columns must be considered in locating luminaires. Since these details introduce much more complexity into the design of the lighting system, they are not considered in the examples shown in this chapter. However, designers of lighting systems in the real world must be able to read structural, mechanical, and architectural drawings in order to coordinate the lighting systems.

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(a) CFL and HID

Figure 6.47 Layout Arrangements for Luminaires

(b) Flourescent, continuous rows

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6.8—GUIDELINES SPECIFICATION Lighting specifications for luminaires should be clearly described to avoid the substitution of inferior products that might sacrifice performance and energy savings. (Refer to ELI specifications in Appendix B). 6.8.1 Performance Specifications. Instead of specifying a product by name, it is possible to specify a product by thoroughly describing its performance characteristics. Key identifying characteristics are the photometric curves of the luminaire. Like fingerprints, photometric data are virtually unique to each luminaire. Characteristics may include coefficient of utilization, efficiency, distribution patterns, and candela at specific angles. It is especially important to have a performance specification in cases where visual performance may be impaired by poor luminaire characteristics as in, for example, VDT areas. It is also advisable to include construction parameters when writing a performance specification. Material gauge, construction method, tolerances, and other quality factors should be included to prevent substitution by photometrically correct but otherwise inferior products. Finally, the performance specification should require certified test data from an independent laboratory using IEC recommended testing methods.

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Chapter 7. Lighting Control Technologies

7.1—LIGHTING CONTROL STRATEGIES The 3 main purposes for the use of lighting controls are:

• Energy Management • Aesthetics • Code Compliance

Energy management controls for lighting systems provide energy and cost savings through reduced power or reduced time of use. Aesthetic controls provide the ability to change space functions and can create emotional appeal, offering control of lighting quality, mood, and attitude. Power density considerations are often given for control systems, providing additional lighting to be used in a space, or to reduce overall energy consumption to meet code requirements. 7.1.1 Energy Management Strategies

(a) Forecasted Schedule. Wherein the activities in a building occur routinely during the day, luminaires throughout the space can be operated on a fixed schedule (with overrides in case there are variations in the schedule). For example, staff arrival and departure times, lunch times, and cleaning hours are forecasted activities and schedules.

Forecasted scheduling strategies are particularly effective when work

schedules are well defined for the entire area. These strategies can reduce energy consumption by as much as 40 % by eliminating energy wastage caused by lights operating in unoccupied spaces. Automatic scheduling also frees the staff of the burden of operating lighting controls and can be used to signal times of particular activities, such as opening and closing of retail stores.

CHAPTER 7. LIGHTING CONTROL TECHNOLOGIES

(b) Un-forecasted Schedule. Many situations are unscheduled, such as workstations vacancies due to sickness, vacations, staff meetings and business trips. Unassigned areas such as comfort rooms, copy centers, conference rooms, filing areas, etc. are used (sporadically) in a wide range and are not readily scheduled. Although these areas may not be open to tightly scheduled lighting operation, local automatic control techniques can be more cost effective than to rely on manual operation of lights. Unforecasted scheduling strategies using occupancy/motion sensors have yielded energy savings of over 60 % in some areas.

To assess the benefits of automatic controls, it is important first

determine the proportion of time the space is vacant. It is also important to consider that switching lights on and off can disturb occupants of adjacent spaces, as in an open-plan office. For reasons of aesthetics, safety, and user acceptance, lights in these spaces can be dimmed rather than switched off completely.

(c) Daylighting. In the perimeter areas of buildings, part of the

illumination can often be provided by daylight. In these areas, reduction of power for electric lighting in response to the amount of available daylight reduces energy consumption.

Both dimming and switching strategies can be used. Successful

applications of daylight based switching, high levels of daylight must be present so that sufficient illumination for the task remains after the electric lighting has been lowered.

Energy savings realized from daylighting depends on several factors,

such as climatic conditions, building orientation, design and shape, sensor and control design and installation, and the activities within the building. In some conditions, daylight can reduce energy costs significantly when photoelectric sensor controls are used. It is therefore important that control of lighting be properly integrated with daylighting illumination pattern to maintain adequate illumination and quality of lighting. It is important during peak power demand hours when cost of energy can be much higher than off-peak hours.

Photo sensor controls, the size and form of control zones are usually

constrained by the rapid falloff of horizontal illumination from the

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window wall. Lighting zones can be laid out to cover a single task area, a room, or an entire building. In practice, the lighting zones should be adjacent to the window wall and no more than 4 meters deep. A separate control should be provided for the row of luminaires nearest the window. Occupancy sensors available today can have daylight sensing features.

(d) Brightness Balance. Lighting design often dictates limit to the

brightness within spaces. The design objective is to balance different brightness levels so that glare and shadows be reduced. Lighting controls can be used to mitigate the brightness produced by windows in interior spaces. The control technique is to limit light entering the space with blinds or louvers. A counterintuitive approach for interior spaces is to increase the illumination produced by artificial light. Often controls can be used to hide a luminous transition between two spaces having different brightness levels.

(e) Lumen Maintenance. Lighting systems are designed for a

minimum maintained illumination level. This requires the level of a new lighting system to exceed the design minimum by 20 To 35 % to allow for lamp lumen depreciation, luminaire dirt depreciation, and room surface dirt depreciation.

Lumen depreciation control strategy calls for the reduction of the

initial illumination of a new system to the designed minimum level. As lumen depreciation occurs, more power is applied to the lamps in order to maintain constant output. Therefore, full power is applied only near the end of the lumen maintenance period, significantly reducing energy consumption over the life of the lamps.

Lumen maintenance can be done by the use of a dimming system

with photo-sensor input. The control system for lumen maintenance is most cost effective when large portion of luminaires are controlled together. Group relamping is to maintain all the lamps at the same lumen output. This is required for the system to be effective in reducing energy and maintenance costs.

(f) Task Tuning. With a task tuning control strategy, the lighting

system can be adjusted, tuned, to provide local illumination as needed. Levels can be lowered in areas such as aisles and reception rooms and

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raised in areas where more difficult visual tasks occur. Significant savings are possible through task tuning. This strategy results in the efficient use of energy for lighting without sacrificing occupant visual performance.

Tuning is done by varying the light output of individual or small

groups of luminaires. It is necessary to tune the lighting only occasionally, upon a change in the space utilization or in the task being performed, the adjustment often can be done manually. Light controllers have features to tune up a zone of luminaires.

(g) Load Shedding and Demand Reduction. An electrical bill of a

building can be effectively reduced by controlling lighting power demand for short periods of time. Selective reduction of illumination in less critical areas can be effective in regions where peak power demand occurs in summer,. This is because a reduction in lighting load also reduces the cooling load. Peak power demand charges are used by many utilities to help avoid voltage outages, so the savings at peak periods can be significant.

(h) Aesthetic Control Strategies. Many spaces in buildings are used

for more than one purpose. Different tasks need a variety of lighting conditions. Aesthetic controls include switching and dimming. Dimming controls can provide dynamic effects or create a smooth transition between different room functions.

It is necessary to control illumination over a wide range for Aesthetic

applications. In a conference room, for example, a high illumination would be needed for reading tasks, while for a slide presentation the illumination should be 1/10th or less of the reading level. The differences in required illumination are due to the differences in the task visibility and the adaptation of the eye to changes in illumination. The square law curve for adaptation used by most controls generally require a measured illumination of less than 10 % depending on the room reflectance, the screen used, and the degree of note taking required.

It is necessary to use a light source that can be appropriately

dimmed. Incandescent and low voltage incandescent sources can be dim to zero output. Fluorescent sources can be dimmed to 1 % output when

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used with certain dimming ballasts. Neon and cold cathode lamps can be dimmed to approximately 10 % of maximum light output. HID sources can be dimmed to approximately 20 % of maximum light output, but they have a slow response time and strong color shifts, which make them poorly suited for aesthetic applications.

The strategies used for aesthetic control include manual controls,

preset control systems, and central control systems. Manual controls (switches and dimmers) are used in schools, residential, commercial and industrial buildings. To be effective, manual controls must be simple and convenient to use. The number of controls should be minimized to avoid confusion. Control panels should be clearly and permanently labeled. Switches and dimmers should match each other and fit into the overall architectural style of the area to be lighted

Preset control systems provide several lighting points to be

controlled simultaneously. All points are programmed to provide multiple scenes or moods. Each of these moods can be recalled with the touch of one button. Preset control systems are valuable in multifunction commercial areas such as ballrooms, conference rooms. They are also used in residential applications.

Central dimming systems are the most effective of the group of

dimming options. Similar to theatrical dimming systems, they have at least one central dimming panel with dimmers suited for the type of load. The dimmers are themselves the power handling devices. The control function logic is typically in the control panel, which can include processors and several forms of preset and manual controls.

Local, single room control systems composed of one control station

with manual sliders or non-dimming switches that can control large amounts of power. The dimmable wattage is limited only by the number of modules a dimmer panel can preset, assigned, and time clock control. They can include energy reduction controls such as occupancy/motion sensors and photo-sensors and can handle emergency power functions. Some systems allow wireless remote control and can interface to audiovisual and other systems in both residential and commercial applications.

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In divisible areas, assignment control points allow many independent lighting systems to be joined together through flexible master control. Convention Center and Hotel function areas are the most common applications.

Whole house systems are being applied more frequently today.

Using local or small modular dimmers, a central computer, and master control station, these systems can control all lighting features. Several of these systems can also operate other electrical systems such as whirlpool pumps, motorized curtains, and interface easily with burglar alarms, smart home systems and other electrical control systems.

7.2—LIGHTING CONTROL TECHNIQUES Selection of the major control technique is important in the specification process. There are three categories that establish the major selection; switching or dimming control, local or central control, and the degree of control automation. Once the strategies are decided, it is necessary to select the specific lighting control equipment to be employed. 7.2.1 Switching or Dimming Switching can be done manually with simple wall box switches, remotely via relays or switchable circuit breakers, by a control system, or by occupancy sensors. It has been found that where the use of local switching controls can save energy, switches might be used. Two-stage switching in private offices is an inexpensive way to give the occupant the ability to modulate the environment in response to daylight or specific task requirements. To achieve a different switching light level, it has to be done through light level switchable ballast. Instead of switching between lamps, the light level switchable ballast can reduce the light from all lamps in the luminaire. Central switching systems can be less expensive to install per unit area than equivalent dimming systems and the most applicable strategies such as scheduling, where the switching action can be confined to unoccupied times. Switching techniques should be treated carefully for other purposes, especially if the switching action can occur when the space is

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occupied, because sudden changes in the electric lighting can annoy building occupants, thus affecting productivity. In multi-ballasted lighting systems, switching can be used most effectively if the luminaires are split-wired. Split wiring 3 and 4 lamp luminaires can provide multiple intensities in a single area. With the aid of a control system, full lighting can be provided for certain portions of the day while allowing a reduction of lighting level for times when less demanding tasks are preformed. In retrofit applications, split wiring can be costly. Depending on the existing wiring system, relays can be installed near the circuit breaker stations to allow automatic control of blocks of lighting. Occupancy or motion sensors can be utilized to control lighting in offices, conference areas, and similar spaces. In these situations, the addition of toggle switches or sensors with override switches to provide the manual off condition for certain applications is recommended. With dimming control, the illumination in each area can be varied smoothly and continuously to dynamically match visual requirements. Dimming control can be well suited to daylighting applications. Moreover, the dynamic range of split wiring scheme allows 3 lighting levels with 4 lamp luminaires. NOTE: under IEC 61000-3-2- Lighting Equipment

1.) Independent Dimming Devices shall comply with class A limits. Where phase control is used on incandescent lamps, the firing angle shall not exceed 1450.

2.) Built-in Dimming Devices for incandescent lamp class A limits shall be satisfied. Where phase control is used, the firing angle shall not exceed 1450. For discharge lamps class D limits apply.

7.2.2 Local or Central Lighting controls can be utilized in buildings using either a local approach, a central system, or some combination of the two. The two approaches are distinguished by the size of the controlled spaces and by how the control inputs are integrated into the system.

A local lighting system is divided into independently controllable areas, their size and form typically dictated by the geometry of the building areas or according to functional needs. Sensor inputs are wired directly to

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the local lighting and HVAC control rather than to a central location. Therefore, each module is essentially independent of other modules. Sensors that can detect daylight availability can be especially effective in these situations. Central systems generally combine several local areas. Some central microprocessor systems are intended to handle either the lighting and mechanical (HVAC) systems or both. Total building energy management control and monitoring functions are easier with central systems.

7.2.2.1 System Integration. One advantage of a lighting control system is that the illumination can be automatically adjusted to suit the activity or tasks. With proper programming and appropriate sensors, some processors can control the lighting systems as well as the mechanical systems of the building. A common system allows the optimum control of energy use and also minimizes programming and training needs. By the use of distributive processing configuration, the difference between mechanical and lighting inputs and control strategies are easily meet. The local processor can be designed for the specific inputs and control outputs as well as the needed interface with the central processor.

All lighting control system has 3 major components: a logic circuit, a

sensing device, and a power controller. The function and wiring system must link these components. The controller such as switch, relay or dimmer is the business end of a control system that changes the output of the light source. The logic circuit is the one that decides when to supply electric lighting and the intensity. It receives the information from the sensor. Several sensors can be combined in a single system.

Control strategies can have different and overlapping sets of

hardware requirements. Some combination of strategies, such as daylighting and lumen maintenance, the equipment needed is essentially identical to that needed for both. Therefore, the economic benefit of employing several strategies with the same equipment can increase the cost effectiveness of the control system investment.

7.2.2.2 Hardwiring. There are several methods available for linking

the lighting control system elements. The control device itself is usually

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hardwired to a lighting system before the supply and the ballast. Some electronic ballasts incorporate circuitry to vary the output of the light source over a wide range, effectively combining the control equipment and ballast into one integrated package.

7.2.2.3 Power Line Carrier. The power line carrier is a

communication method that is looking for some application in retrofitting control installations. By permitting communication between the processor and the control equipment directly over the existing power lines, extensive rewiring is being eliminated. Moreover, some wiring systems in older buildings can significantly reduce the effective range of communications between the sensor, the processor and the controller. There are limitations to capacity and speed of these systems. Care must be taken to ensure that all of the control equipment on the power line is compatible as a system and suitable for the application. Several factors contribute to a successful installation, but often poor power quality and pre-existing power line carrier systems can compromise the proper operation of these systems.

7.2.2.4 Radio Links. Radio-controlled system eliminates the need

for wiring between the sensor, the processor and the controller. These systems are expensive but have some applications in outdoor systems and high bay warehouses where the controlled luminaires are difficult to access and maintain. They are also suited for retrofitting where control wiring would be difficult or expensive to install. 7.2.3 Degree of Control Automation and Zoning Controls vary in degree of automation, from manual to highly automatic. In terms of energy conservation, automatic controls can reduce energy consumption since they do not depend on human activity. In terms of cost and occupant response, automatic controls are not the most effective. Permitting occupants to override the automatic operation when needed is very important, especially when programmable controls are utilized for scheduling purposes. A strict lighting schedule can be applied if automatic control can be locally overridden when necessary.

7.2.3.1 Zoning. Compliance with energy codes needs much closer coordination between the electrical engineer and the mechanical engineer

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who design the HVAC system. Lighting and mechanical areas should match for coordinated control. In most cases this results in areas sized from 80 m2 to 300 m2. There is a tradeoff between the size of the control area and the cost of the system. Smaller areas are more costly both in equipment and in installation cost but have greater flexibility and potential for lowering lighting operating costs. Some control strategies, especially day lighting and task tuning are best applied with small control areas, 10 to 40 m2, while scheduling and lumen maintenance can be used effectively even if the control areas correspond to the area illuminated by an entire branch circuit, approximately 100 to 4002.

7.3—LIGHTING CONTROL EQUIPMENT 7.3.1 Manual Switching The energy savings attainable through switching should be the initial consideration in developing the plan for lighting circuits. The most common practice is to permit manual control of lighting. The design and the location of the manual control affect the energy consumption of the building. The energy savings depend on the willingness of the persons to utilize the switching system; the convenience and flexibility of switching greatly affect the extent of any lighting energy savings. Occupants of private offices are the most likely to use switches to modulate the illumination in their area and to do their part in saving energy. Light reminder stickers can improve occupant’s switching behavior. Each lighting plan presents a unique set of switching circumstances. The following general provisions should be considered:

1. Each office or space should have its own control switch, and those with daylighting should have at least two-level switching.

2. In large open areas, similar work areas should be grouped together on one circuit.

3. When single or two lamp luminaires are used, adjacent luminaires should be placed on alternate circuits to provide for half and full illumination.

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4. When three lamp fluorescent luminaires are used, the middle lamps should be connected to a separate circuit from the outer lamps. This produces three level lighting systems with one-third, two thirds and full light levels.

5. When four lamp luminaires are used, the inside pair of lamps should be connected to a circuit separate from the outer pair to provide half and full light levels.

6. Task areas high illumination should be on separate switches. 7. Luminaires along windows should be wired on separate

circuits and controlled independently. 8. Effective labeling may cause occupants to use simple wall

switches. 7.3.2 Timing and Sensing Devices

7.3.2.1 Timing Devices. The function of the timer is to control lighting in response to known or scheduled activities of events, wherein; turning of lights that is not needed is achieved. Timers range in complexity from simple integral timers to microprocessors that can program a sequence of events for years at a time. Coupled with microprocessors, timers can control multiple events and lighting effects. As a general rule, some form of override must be provided. To accommodate deviation from the preset schedule, the override should automatically reset to the programmed functions after a suitable period. Such timers can be effective in bathrooms in hotels, communication equipment rooms and certain stack applications where occupancy sensors cannot effectively cover the whole area.

With a simple integral timer, the load is switched on and kept

energized for a preset time. Timer limits range from a few minutes to twelve hours. Some models have a hold position for continuous service. These units can handle lighting loads of up to 20 amperes.

An electromechanical timer is driven by an electric motor, with

contacts actuated by mechanical stops or arms affixed to the clock face. Timers have periods from 24 hours to 7 days and can include astronomical correction to compensate for seasonal variations. They can initiate numerous on-off operations. Some units are available with up to 16 hours of back up power on the timing mechanism in case of power

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failure. Some can actuate a momentary contact switch to provide on and off signals for actuating low voltage relays. Wall mounted units are also available to control local loads such as security lighting.

Electronic timers provide programmable selection of several

switching operations and typically can be controlled to the nearest minute over a 7-day period. These devices offer the same switching options as the electromechanical timers. Battery backup is available to protect the system from power failures.

7.3.2.2 Photo-sensors. Photo-sensors use electronic components that

transform visible radiation into an electrical signal, which is then used to control another system. Generally these sensors are either immune to or filtered from UV and IR radiation. Some sensors generate a control signal roughly proportional to the irradiance on the photo sensor. The control signal can activate two modes of operation. The first, the photo-sensor output activates a simple on-off relay. The second, a variable output signal is made and sent to a controller that continuously adjusts the output of the lighting system.

When photo sensors for interior applications are used in connection

with relays for on-off control they should use a “dead band”, that is, the illumination above which the lamps are switched off should be higher than the illumination below which they are switched on. These prevent unnecessary on-off cycling near the threshold illumination levels. It is also important to consider that switching lights on and off can disturb occupants. A photo sensor can be an integral part of a luminaire, can be remote from the luminaire that it controls, or can control a relay that operates several luminaires. A photo sensor can also be used in conjunction with a timer which can switch lights off or lower their output.

Photo sensors used in outdoor applications are usually oriented to the

north. This assures more constant illumination on the sensor, as there is no direct sunlight contribution. The sensors are adjustable with respect to light levels for activation. Photo sensors designed for outdoor lighting should not be used to control interior lighting because of their limited sensitivity and adjustability.

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Systems that continuously vary their output disproportionately in response to varying photo sensor irradiance are cost effective when used for window or daylighting strategies. The photo sensor detects an increase in illumination and sends a mix signal to the controller to decrease the illumination from artificial lighting source. These systems can be adjusted by stepped or continuous dimming and are effective when used for lumen maintenance.

The use of photo sensors to control interior lighting is not trivial;

proper design, placement and calibration are critical. Several techniques are presently used. Placement of the sensor on the task surface has the advantage of direct measurement of task illumination but there can be difficulty in wiring the sensor to the controller and in ensuring that the sensor does not damage and is not damaged by the task materials. The second and most common method places the sensor on the ceiling, oriented toward the task. Third method measures the daylight entering through the fenestration; best results are achieved when sunlight does not directly shine on the sensor. A fourth method measures the external illumination directly. All methods need the sensor output to be adjusted to match the illumination on the task as nearly as possible. An accurate and easy means to calibrate the response of the sensor is essential. Lumen maintenance strategies typically use the second method, and daylighting strategies can use any of the three methods.

Another consideration with interior lighting is the amount of area

controlled by one sensor. The most important guide is that all of the areas controlled by one sensor should have the same task activity, illumination requirements and the surrounding. The space controlled should have the same daylight illumination conditions. The entire area should be contiguous, having no high walls or partitions to divide it. This is effective only if the task area monitored is truly typical and free of brightness extremes.

7.3.2.3 Occupancy/Motion Sensors. The primary function of

occupancy sensors is to automatically switch off luminaires when spaces are unoccupied to reduce energy use. Electrical consumption is reduced by cutting the number of hours the luminaires are operating. This method offers the best savings and payback of all control options. The failure of

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an occupancy sensor installation is almost always a result of poor sensor placement or incorrect equipment selection.

Occupancy/motion sensors provide local on-off control of luminaires

in response to the presence or absence of occupants in a space. Occupancy is sensed by audio, ultrasonic, passive infrared, or optical means. These devices are designed to switch lights on as an occupant enters and keep them on while he or she remains in the space; lights are switched off after a preset time following the departure of the occupant. The normal movements of a person should sustain lighting in the occupied space. Inactive and quiet activities such as word processing, reading or using telephone, however, may not be detected and lights being switched off can frustrate occupants in these situations. These nuisance actions can be minimized by suitable product selection and proper sensor location. Occupancy/motion sensors can be mounted in many ways; they can be recessed or surface mounted on the ceiling, corners, or walls; they can replace wall switches; and they can plug into receptacles. The floor area covered by individual sensors can range from 15m2 in individual offices or workstations to 200 m2 in large assembly areas. Larger areas can be controlled by adding more sensors.

When selecting a sensor and planning for its location, the designer

should ensure that all important movements within the controlled area are detected subject to the avoidance of false positive responses; responses to movement by inanimate objects inside the room or by people outside the entrance. It should also be recognized that the operating life of lamps can be reduced by ballast starting circuitry, and frequency of switching.

Large areas can require multiple sensors and power devices for

multiple circuits. Several combinations are available, with remote sensors, a variety of sensor technologies and coverage patterns, and voltage specific power packs.

Ultrasonic occupancy/motion sensors transmit a low power, high

frequency signal and receive a reflected signal using the Doppler shift to sense movement in an area. The frequency of ultrasonic sensor is usually between 25000 and 40000 hertz. Ultrasonic occupancy/motion sensors are normally better at detecting small movements and detecting

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movements around modular walls. Most ultrasonic occupancy/motion sensors should not be mounted on ceilings above 4 to 5 m.

There have been reports of ultrasonic occupancy/motion sensors

interfering with hearing aids. Passive infrared (PIR) sensors detect the changes in infrared patterns

across their segmented detection areas, tuned to the region of human body temperature. PIR occupancy and motion sensors have a line of sight coverage pattern with very predictable pickup patterns. They can be masked for controlling unwanted coverage.

7.4—IMPACT OF LIGHTING CONTROLS

HVAC Effects. Lighting can be responsible for a major portion of a building’s HVAC load. Therefore, lighting loads have major influence on both air conditioning loads and fan operation. Lighting loads affect the initial cost of the HVAC system as well as its annual consumption. If lighting controls are utilized to reduce the lighting consumption, it is important that the HVAC system and controls be designed to respond to changes in the operation of the lighting system. With the trend toward the use of daylighting to augment the lighting system, it is necessary to consider the effects of the glazing system on the heating and air conditioning system and its controls. Daylighting can increase the initial cost and the annual consumption if daylighting system is not carefully designed. Several modern occupancy sensors have dedicated control output for the simultaneous control of lighting and HVAC equipment. By properly integrating the HVAC system and its controls with the lighting system often both the initial cost of the HVAC system and consumption can be reduced. In order to achieve these benefits, the HVAC system must be properly designed with zoning and effective controls. The type of HVAC system is extremely important if full savings are to be attained from lighting controls. Especially in existing buildings where the air distribution system is either multi-zone, double duct or terminal reheat system. These systems supply a constant amount of air and vary the supply air temperature in order to maintain the area temperature.

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In building designs, the use of multi-zone and terminal reheat systems has been eliminated by building energy codes. Most commercial systems use numerous small single zone units or variable air volume (VAV)systems where the area temperature is maintained by an air supply of a contant temperature and varying volume. Lighting controls can be integrated with HVAC system within the building energy management and control system (EMCS). The primary application is the scheduling of the start and stop of various loads. The EMCS computer can also be used to consider the time of imposition of the various loads needed for optimal start and stop and the thermal storage effects of the building mass. Another consideration that affects energy consumption of the air conditioning system is the part load efficiency of the air conditioning, including the energy dissipated by fans and motors. Unless the air conditioning components and controls are designed to take into account the part load efficiency, the potential savings of air conditioning system from lighting controls will not be achieved. 7.4.1 Electrical Equipment Effects

7.4.1.1 Switching. Controls that switch lamps on and off excessively can reduce fluorescent and HID lamp life. Increased cycling does not decrease ballast life and reliability. The actual service life of lamps can be extended by eliminating of unnecessary burning hours.

7.4.1.2 Interference. Radio Frequency Interference (RFI) or

electromagnetic interference (EMI) is inherent in all control systems that rapidly switch a portion of input power.

There are two areas of concern with regard to radio noise: conducted

emission and radiated emission. Conducted emission is the noise fed directly into the power line by the device drawing power from that line. Radiated emission is the electrical noise radiated by the lamps in the luminaire, with the power line possibly acting as an antenna. Conducted emission follows the power line itself as a path of propagation. Generally, at high frequencies this noise is limited to the downstream

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portion of the circuit, from the branch transformer to the devices in question.

In most commercial and industrial buildings the lighting power

circuits are contained within metal conduits. These conduits attenuate radiated electromagnetic energy and limit the radio noise to the circuits contained within the same conduit. Conducted emissions are of concern to the extent that they interfere with the lighting control system and any other devices on the same branch circuit feeds, such as computers or security systems. Control systems use passive and active filters to keep the conducted emissions within allowable limits.

With shielded power lines, radiated noise is limited to the radio noise

emitted directly from the controller and luminaire. It is of concern to the extent that other devices within the immediate area of the controller and luminaire can be affected. The primary antenna within the luminaire is the lamp itself. While all ballasts, lamps, and control systems emit radio noise that can interfere with some equipment. There are precautions that ballast and control manufacturers can take to reduce such noise. For conventional ones, the noise is a type and magnitude that can be more easily suppressed or designed out of the ballast. There are also luminaires with conductive lenses specifically designed to attenuate the EMI radiated by the lamps. 7.4.2 Power Quality The power quality of electrical switching systems has become a concern to utilities with regard to power factor, safety and interference. Most incandescent dimming techniques use phase control in which the voltage to the lamp is reduced by high speed switching. This distorts the sinusoidal line current, producing other frequencies and leading to a decrease in the power factor. The designer should be aware of potential harmonics as they can overload the neutral conductor in three phase electrical distribution systems, which can damage its insulation, overheat transformers and distort the voltage at points of coupling. In addition, if only a single leg of a three phase system is dimmed, the system becomes unbalanced, further increasing the neutral current. In practice no problems have

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actually been attributed to the generation of harmonics by lighting control systems to date, but designers and engineers should become familiar with the issues when using these advanced lighting technologies. Very low harmonic content electronic ballasts can have a high in rush current associated with the front end power filtering. Consult the specific manufacturer’s literature for detailed information on this. 7.4.3 Human Performance Effects Lighting control systems can have a positive effect on the working environment, provided that they add to the comfort and the aesthetics of a space. Controls can have further economic benefit if the productivity of the occupants is increased. This is true, for example, where visual display terminals (VDTs) are used because the brightness of reflected images is reduced by dimming the lighting. In general, the ceiling and task lighting can be controlled in zones over a wide range of illumination to adjust the lighting to the specific requirement of the spaces. Care should be taken when attempting to reduce peak power demand or energy use to ensure that illumination is not reduced below the requirement for visual tasks in the space. Audible noise, flicker and source color changes caused by dimmer controls can also affect performance.

7.4.3.1 Illumination. The illumination determines the visual adaptation level, which has been demonstrated to affect performance in visual tasks such as reading, inspecting and assembling. Control systems must be designed so that the lighting system can provide proper illumination for these tasks.

7.4.3.2 Audible Noise. Lighting control systems can produce audible

noise in the environment, which can be a source of annoyance. The manufacturer should be consulted to minimize the noise produced by the control system. Noise control strategies include careful lamp selection, enhanced dimmer filtering and remote dimmer locations.

7.4.3.3 Flicker. Controls that modify waveforms can cause excessive

flicker. Flicker is noticeable if the variation in light amplitude is

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sufficiently high. Even imperceptible flicker can cause eyestrain and fatigue at 50 Hz. While theoretically less of a problem at 60 Hz, some people are still sensitive to flicker. Proposed control systems should therefore be examined for their effect on flicker.

Flicker is typically greater with uncoated HID lamps than fluorescent

lamps. This is because the phosphors in a fluorescent lamp continue to generate light throughout the ac cycle. Most phosphor coated HID lamps exhibit this reduced flicker. HPS lamps have high flicker because of the rapid recombination of sodium ions. Lamps should be selected that minimize flicker. Electronic fluorescent and HID ballasts should be selected because they drive the lamps without flicker. Flicker reduction can be attained with HID lamps by placing luminaires in room on different supply phases.

7.4.3.4 Color Changes. During lamp dimming, there can be a small shift in lamp color with fluorescent lamps. This color shift is not usually considered significant, but it is noticeable, especially with warm CCT lamps. Other light sources including incandescent lamps exhibit a more significant color shift. Care must be exercised when using such lamps. They should not be dimmed to levels that alter the aesthetics of the space, cause discomfort to the occupants, or affect tasks in which color rendition is essential. One approach is to limit the range of dimming so that no color shift is apparent. On the other hand, the shift in incandescent lighting to a lower color temperature by dimming can actually be desirable in certain applications, such as restaurants, where a warmer atmosphere can be inviting.

7.5—COST ANALYSIS The approach used to evaluate the economics of lighting systems can be extended to include systems with controls. Basically, the procedure involves adding the cost of the control system to the rest of the lighting system equipment costs and determining how the use of the controls affects operating costs. Since lighting controls can affect not only the operation of the lighting system but also other building energy systems, all of the system interrelationships must be considered. In office buildings, for example, lighting controls that vary the output of the

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general lighting in response to daylight, also change the amount and location of heat generated in the building. As the building’s cooling system take this into account, the HVAC costs are affected. Some lighting control systems can also affect the electrical system by changing the power factor, high in rush currents and high harmonic currents, the performance of the lighting system itself can be altered in terms of efficacy, lamp life and ballast life. Energy savings depend on the size of the space, availability of daylight, work schedule, activities being performed and the attitude and training of the occupants. To estimate the energy that could be saved by using automatic controls, the areas to be controlled should be divided into small areas of similar function and occupancy, such as private offices with windows and open-plan sales offices. Users should establish a valuable use scenario for each small area, including:

• Hours of use • Fixed or flexible work schedules • Weekly, monthly, or yearly changes in schedule • Periods when areas are unoccupied • Cleaning crew schedules • Use of daylight to reduce electric lighting

7.5.1 Cost Considerations Some costs normally associated with the installation and operation of lighting control systems include:

• Control hardware, including sensors, control and monitoring station equipment, cabling and over current protection

• Interface equipment • Installation and setup labor • Maintenance labor and spare parts • Energy costs and utility rate structures

7.5.1.1 Economic Analysis Techniques. Lighting controls are

frequently cost justified on the basis of expected energy cost savings over a period of time.

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7.5.1.2 Sources of Cost and Performance Data. Although cost information for lighting control hardware is easily obtained, performance information that affects operating and other system cost is not readily available and can be site specific. The main operating cost factors are the system input power and operating hours. Accurate estimates for on-off control systems can be made if the operating period of the system is known, but the systems with variable power inputs must be measured or carefully simulated. It can be helpful to construct a profile of system input power versus time or use computer modeling, especially if daylighting, time of day utility rates, or other special considerations apply.

Studies reveal that the impact of occupancy sensors is highly

dependent on the application. The energy reduction attained from the proper use of occupancy sensors has been measured to be from 10 to 50 %.

7.6—Digital Addressable Lighting Interface (DALI) DALI is the new interface standard for digital ECGs (IEC 929), and enables all the necessary functions of ECGs to be controlled digitally. A DALI ECG is capable of carrying out commands from a controller; its capabilities go far beyond that of the traditional analogue 1-10V interface. There are three main criteria defined by DALI systems:

• Digital addressability • Digital processing • Digital communication

DALI was created by all the leading ECG manufacturers acting together to define the functions of a DALI ECG and DALI- compliant loads in a lighting system. It enables ECGs to send status messages and store scene values. Each DALI ECG can store 16 group assignments and 16 scenes. DALI is not a system but an interface definition. Not all digital-ECGs or digital light control systems are based on DALI and therefore may not be compatible. If the products comply with the

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DALI standard, the products of the different suppliers can be combined with each other; however, the modules may provide different features. 7.6.1 DALI Advantages to Lighting Designers The DALI technology provides many key benefits for lighting designers such as:

(a) Simple Wiring of Controls. Hardwire control groups are eliminated; each individual device has only a power input and digital control input which are non-polarized, eliminating potential costly installation errors. Controls are wired using the same type of standard wire as is used for power.

(b) Control of Individual Lights. Up to sixteen (16) different light

levels, fade times and rates can be programmed and stored in the ballast memory. Each DALI loop can support up to sixty four (64) individual addresses.

(c) Flexible Group Control. Each DALI loop can support up to

sixteen (16) individual groups and each ballast may belong to any or all of the sixteen available groups for unpararelled lighting scene definitions. Simultaneous control of all units is possible at any time through broadcast addressing. Software control allows easy configuration and modification. Dimming specifications can be finalized much later in a project and buildings can be adapted more easily to meet client’s future needs. Lighting designs can be programmed and simulated on a PC for later downloading into the installation. This commissioning method also offers the flexibility of room layout changes without rewiring. Simple interface with Building Management Systems (BMS) DALI can add valuable extra flexibility through its feedback of lighting system information to the BMS, allowing automatic identification of failed lamps and ballasts as well as central monitoring of ballast power and dimming levels. In the simplest situation, the BMS can be used for central overrides such as timed on/off switching or dimming.

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7.6.2 DALI Advantages to Facility Managers

(a) Increased Space Flexibility. Various instructions can be programmed to accommodate different lighting tasks and situations, such as:

• Meeting spaces that require different lighting scenes for

multiple types of uses or events • Open offices where users can control their own lighting • Areas such as lobbies or restaurants that reflect time of day

lighting changes (b) Simple Modification. Lighting modifications in response to

changes in area usage or occupancy are done quickly and easily through a PC, PDA or infrared (IR) remote control. No rewiring is needed.

(c) Low Maintenance Costs. Diagnostic status of each ballast and

lamp is fed to a central monitor for proactive identification of failures or non-responsive fixture. Multiple service trips are eliminated.

(d) Energy Savings. Energy consumption can be reduced by 30-60

% through day lighting (dimming of lamps in response to changing amounts of natural light) and switching strategies such as occupancy sensors and scheduled on/off switching. Peak demand charges can also be avoided with well-planned control set points. 7.6.3 DALI Advantages to Building Occupants

(a) Customized Lighting Preferences. Any combination of ballasts can be grouped and controlled to accommodate the preferences of individual building occupants.

(b) More Comfortable Lighting. Continuous automatic adjustment

of fluorescent lighting in response to changing ambient light levels provides a constant light level on the working surface. Logarithmic dimming technology matches the eye’s sensitivity. Eyestrain is also eliminated due to better flicker management of luminaires.

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(c) Individual Control. The DALI system can be configured to allow the occupants control and fine-tuning of light levels.

(d) Easy Modification. When needs change, ballast can simply be

reprogrammed instead of disruptive moving and rewiring of fixtures.

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Chapter 8. Lighting System Design

INTRODUCTION The design of a lighting system for indoor and outdoor general illumination is considered to be more of an art than a science as described in Chapter 1 and involves many variable factors. The factors for indoor include the size and shape of the space; the types of finishes on the ceilings, walls, and floors; the details of the construction; the economic considerations of both the initial and the operating costs; the compatibility of the lighting system with the architectural design; and the type of activities that will be carried out in that particular area. For the outdoor, only the light that reaches the surface directly from the luminaire is considered. Light reflected from surrounding surfaces may be ignored. Light control is very important as well as proper beam spread selection.

8.1—BASIC INDOOR/INTERIOR LIGHTING DESIGN

The fundamental requirement for the design of indoor lighting system is to provide sufficient light for the performance of the visual task to enable the person to do these tasks efficiently and accurately, and at the same time to create a comfortable environment with a minimum of eyestrain and fatigue. It also promotes safety by preventing accidents often caused by poor visibility. The designer must have some information about the visual tasks, as follows:

• Usual task to be performed;

CHAPTER 8. LIGHTING SYSTEM DESIGN

• Age of person who will perform the task; • Importance of speed and accuracy; • Design of surrounding area (reflectance of task background).

8.1.1 Objectives and Design Considerations.

On the basis of design consideration, the designer must first and foremost determine the objectives and purpose in the design of interior lighting as shown below:

(a) Seeing Task (Determination of the Required Level of Illumination) Providing proper lighting for the seeing task is the basic reason for the design calculation. Seeing tasks relating to different areas (i.e. offices, schools, industries, and institutions) are shown in Appendix C with recommended illumination level.

(b) Quality Required. The quality of light involves the comfort of the seeing environment. The factors to consider for quality of light are glare, luminance ratios, diffusion, and color. Since lighting quality requirements vary with the application, specific recommendations and suggestions are given in the same Appendix as stated above.

(c) Quantity Required. The quantity of light involves adequate levels of illumination for the average person under normal condition.

(d) Area Atmosphere. Analyze the environment in which the lighting system will operate. For example, are dirt, water vapor, explosive gases or corrosive vapor present? Dirt may be classified as adhesive, attracted or inert and it may come from intermittent or constant sources.

(e) Area Description and Use. A complete description is required for each area to be lighted. This include the physical characteristics such as room dimensions, room reflectances, work locations or location of work-plane, and the operating characteristics of the lighting system such as the hours of operations per day (hours per start for fluorescent lamps) and annual hours of use of the system.

(f) Selection of System and Luminaire. Selection of the type of luminaire for a given application depends upon the requirements and

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conditions found in items (a) to (e) above and are classified on the basis of their distribution pattern; that is, on the relative amount of light projected upward and/or downward from the luminaire. Most manufacturers list these as direct, semi-direct, general diffuse, direct-indirect, semi-indirect, and indirect. (See Chapter 6 – Lighting Systems and Luminaires.) 8.1.2 Determining Average Illuminance The average illuminance level can be determined when a given number of luminaires that are used in a space is known. Alternatively, the number of luminaires can be determined given the average illuminance level. This calculation method is called Lumen or Zonal Cavity Method. The Lumen or Zonal Cavity Method calculation is preferable when applied to interior task-oriented spaces for a general uniform lighting system. This method assumes the following conditions:

• the room is empty, • the room surfaces are diffuse, • the illuminance on each surface is uniformly distributed over that

surface, and • the width to length ratio is approximately 1.0 to 1.6.

Within the room, the illuminance is determined based on the

horizontal plane, which is considered as the work plane. The work plane is measured at the height of the visual task. In an office, this would generally be at a height of 0.75 meter (around 2.5 feet) above the floor, the average office table height. In the corridor, the work plane is usually considered to be the floor. However, it is worthwhile to note that the Lumen Method is not a complete design method since this horizontal illuminance is just one of the many considerations in the lighting design process. The general equation for the illuminance in a work space is as follows:

EWP = Ø(TOTAL) x CU x LLF AWP

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where: EWP = average maintained illuminance on the work plane, lx Ø(TOTAL) = total system lamp lumen output, lm CU = coefficient of utilization LLF = light loss factor AWP = area of the work plane, m2

Detailed discussions on the above parameter are as follows: (a) Work Plane Illuminance (EWP) is the average maintained luminous flux that hits the work plane per unit area of work plane. It is the amount of light received on a unit area of surface (density). The unit of measurement is lux (lx).

(b) Total System Lamp Lumen Output (ØTOTAL) refers to the quantity of initial light produced by all lamps within all the luminaires that are lighting a space. The computation uses the manufacturer’s lamp lumen rating. The unit of measurement is lumen (lm).

(c) Coefficient of Utilization (CU) is a measure of the efficiency of the system in distributing lumens to the work plane. It is the ratio of the lumens that reaches the work plane to the total lumens given off by the lighting system’s lamps. All lumens from the lamps in the lighting system generally do not reach the work plane. Some of them are absorbed within the luminaire while others by the walls, ceiling, floors and other room surfaces before reaching the work plane. The fraction of the luminous flux emitted by the lamps that reaches the work plane in a space is the coefficient of utilization (CU). See glossary for definition. Coefficient of utilization (CU) would be 0.50 if 50 percent of the light given off by the lamps reaches the work plane. In some cases, the CU can be greater than 1.0. This is because there are recurring reflections, which permit light to hit the work plane more than once. For example, light hitting the work plane can be reflected from the floor, to the ceiling, and back to the floor. It must be calculated each time it passes through the work plane. Thus, in rooms with high reflectances, and for luminaires with a high optical efficiency, the CU can approach and possibly exceed 1.0.

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In the determination of the Coefficient of Utilization (CU), the following factors are to be considered:

(1) Luminaire Efficiency. It is the ratio of luminous flux reproduced by the luminaire to the luminous flux produced by the lamps. The surfaces of the luminaires absorbed some of the lights with efficiencies typically ranging from 50 to 70 percent. Usually, luminaires with higher efficiencies will have higher CU values because they provide more light to the room. The other factors that influence the CU will determine the luminaire efficiency.

(2) Intensity Distribution. The intensity distribution of the

luminaire is the quantity of light reaching the work plane.

Let’s consider two rooms with identical room surface reflectances and both of the same size. Then assume one room contains a luminaire with a widespread distribution, and the other a luminaire with the same lumen output that focuses light toward the work plane. In the room with widespread distribution, more of the light is reflected off the ceiling and walls where some of the light is absorbed. Therefore, less light reaches the work plane. In this case, the room with the widespread distribution luminaire has a lower CU than the room with the more focused distribution, assuming that the two luminaires have the same optical efficiency.

(3) Reflectances. The room surface reflectance is the ratio of the

light reflected from the room surface to the light falling on it. This plays a significant role in combination with the luminaire distribution.

Let’s again compare two rooms of the same size with identical widespread distribution luminaires. One room has dark walls of low reflectance while the other has white walls of high reflectance. The dark wall reflects less light to the work plane due to absorption of more lights. Therefore, dark walls have lower CU than white walls.

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(4) Room Geometry. The room geometry refers to the shape, form or figure of the room surface. It is an important consideration because it affects how easily light can be directed to the work plane.

Let us once again compare two rooms of identical ceiling height and surface reflectances. One room has dimension of 5 m x 5 m while the other has 10 m x 10 m. Both rooms have luminaries spaced at 2.5 m on center. More of the light strikes the work plane in the larger room before reflecting off the walls than small room. Hence, larger room has higher CU since more lights produced by the lamps reach the work plane directly. Assuming all the parameters constant, in wide room with low ceiling, more light will reach the work plane than in narrow room with higher ceiling. Therefore, larger CU values can be expected as the room being considered becomes wider or lower.

(d) Light Loss Factor (LLF). The Light Loss Factor (LLF) is the ratio of the illuminance when it reaches its lower level (just before corrective action takes place) to the initial level. It is an estimate of the conditions under which the system will operate considering the atmospheric conditions, the frequency of cleaning and the depreciation of the lighting effect. Light loss factor is an adjustment to an illuminance calculation in relation to the actual field conditions. It refers to the differences in lamp lumen output, reflectance and transmittance of luminaire components, and room-surface reflectance between ideal laboratory conditions and the actual environment. It is necessary to consider these losses to accurately reflect the system’s performance in a real environment. The total light loss factor (LLF) is the product of all the individual factors that contribute to the loss of light. It is also known as “Maintenance Factor”.

Light loss factor are divided into two categories, unrecoverable and recoverable. Unrecoverable factors are those attributed to equipment and site conditions and cannot be changed with normal maintenance while the recoverable factors can be affected by maintenance, such as cleaning and relamping luminaires, or by cleaning or painting room surfaces (i.e. they change overtime).

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(1) Unrecoverable Light Loss Factor. As stated above, the

unrecoverable factors are those attributed to equipment and site conditions that cannot be changed with normal maintenance procedure such as luminaire ambient temperature factor, heat extraction thermal factor, line voltage to luminaire factor, ballast factor, ballast lamps photometer factor, equipment operating factor, lamp position (tilt) factor and luminaire surface depreciation.

a. Luminaire Ambient Temperature Factor. Variation in

ambient temperature above or below those normally encountered in interiors has little effect on the light output of incandescent and HID lamps, but they significantly affect fluorescent lamps. Each particular lamp-luminaire combination has its own distinctive characteristic of light output against ambient temperature.

b. Heat Extraction Thermal Factor. The heat extraction

thermal factor is the fractional lumen loss or gain due to the airflow. Air handling fluorescent luminaries are integrated with the HVAC system as a means of introducing or removing air from the room. This airflow will have an effect on lamp temperature and consequently on lamp lumens.

c. Line Voltage to Luminaire Factor (Supply voltage to

luminaire). For each light source, its light output is affected by variations in the supply voltage. For incandescent types, small deviations from rated lamp voltage cause approximately three per cent change in lumens for each one per cent change in primary voltage. Fluorescent luminaire output changes approximately one per cent for each two and a half per cent change in primary voltage. See Figure 8.1.

d. Ballast Factor (BF). The ballast factor is the ratio of the

lamp lumens generated on commercial ballasts to those generated on the test reference ballasts. The ballast factor for good quality fluorescent ballasts is nominally 0.95. See Chapter 5 –Energy-Efficient Fluorescent Ballasts.

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Source: Adapted from IES Lighting Handbook, 1995 Reference and Application Volume (New York: Illuminating Engineering Society of North America, 1995)

Figure 8.1 Light Output Change Due to Voltage Change

e. Ballast Lamp Photometer Factor. The ballast lamp

photometer factor is the effect of the temperature within the luminaire when different lamp and ballast combination is used. Initially, luminaire is tested with a particular lamp and ballast combination. When a different combination is used, the effect of temperature relative to a manufacturer’s rated lumens may change. This effect within the luminaire may cause the lamp to operate at less than the rated output. This decrease in lumen is also considered in the determination of the luminaire’s CU.

f. Equipment Operating Factor. The equipment operating

factor is the collective effect on the HID lamps lumen output which depend on the ballast, lamp operating position, and the effect of power reflected from the luminaire back onto the lamp.

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g. Lamp Position (Tilt) factor. The lamp position factor is the ratio of luminous flux in the given operating position to that of in the test position. It is the sensitivity of some HID lamps lumen output to its orientation. Particularly, the metal halide lamps decrease their lumen output when they are tilted from their rated horizontal or vertical position. As in sports lighting, there is a considerable effect when the metal halide luminaires are aimed.

h. Luminaire Surface Depreciation Factor (LSD). Luminaire

surface depreciation results from adverse changes in metal, paint, and plastic components that result in permanently reduced light output. Because of the complex relationship between the light-controlling elements of luminaries using more than one type of material it is difficult to predict losses due to deterioration of materials. No factors are available at present.

(2) Recoverable Light Loss Factor. The recoverable factors are

those that can be changed by regular scheduled maintenance, such as cleaning and relamping luminaires and cleaning and painting room surfaces. These are lamp lumen depreciation, luminaire dirt depreciation, room surface dirt depreciation and lamp burnouts.

a. Lamp Lumen Depreciation Factor (LLD). All lamps

deteriorate in lumen output through life. The light output of an incandescent lamp decreases because of (tungsten) filament evaporation. In addition, for fluorescent lamps, light output decreases as it burns because of phosphor deterioration and loss of active material from the cathodes, which causes tube blackening. Information about lamp lumen depreciation is available from manufacturers’ tables and graphs for lumen depreciation and mortality of the chosen lamp. Rated average life should be determined for the specific hours per start; it should be known when burnouts would begin in the lamp life cycle. From these facts, a practical group relamping cycle can be established.

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b. Luminaire Dirt Depreciation Factor (LDD). With the passage of time, dirt accumulates on the lamps and on the surfaces of the luminaires. This dirt absorbs some of the light. The resulting loss of light is accounted for by the luminaire dirt depreciation factor. Luminaires are divided into six (6) maintenance categories (Category I to VI), which involves the intervals for cleaning (typically in months) and atmospheric conditions (see Figure 8.2). In addition, there are five (5) degrees of operating atmosphere, very clean (VC), clean (C), medium (M), dirty (D), and very dirty (VD). See Table 8.1.

c. Room Surface Dirt Depreciation Factor (RSDD). With the passage of time, the accumulation of dirt on the surfaces of the room further reduces the amount of light that reaches the work plane. The exact effect of dirt on light loss varies according to the size and proportions of the room (that is, the room cavity ratio), the type of operating atmosphere, and the luminaire distribution type. To take this into account, Table 8.2 has been developed to provide Room Surface Dirt Depreciation (RSDD) factors for use in calculating maintained average illumination levels.

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Figure 8.2 Luminaire Dirt Depreciation (LDD) Factors

d. Lamp Burnouts Factor (LBO). Lamp burnouts contribute

to loss of light. If lamps are not replaced promptly after burnout, the average illumination level will be decreased proportionately. For example, when series sequence fluorescent ballasts are used and one lamp fails, both lamps go out. The Lamp Burnout (LBO) factor is the ratio of the lamps remaining lighted to the total, for the maximum number of burnouts permitted.

e. Area of Work Plane (AWP). The area of work plane is the

region of the entire working surface where task is performed such as office table. In other application, for instance hotel lobby, the work plane is the floor area. The Lumen or Zonal Cavity Method calculates the average illuminance of the entire area of the space. In reality, the illuminance level is at its maximum near the center of the room and slightly less towards the walls for a given uniform arrangement of luminaires.

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Table 8.1 Five Degrees of Dirt Conditions Very Clean Clean Medium Dirty Very Dirty Generated Dirt None Very little Noticeable but

not heavy Accumulate rapidly

Constant accumulation

Ambient Dirt None (or none enters area)

Some (almost none enters)

Some enters area Large amount enters area

Almost none excluded

Removal or Filtration Excellent Better than average

Better than average

Only fans or blowers if any

None

Adhesion None Slight Enough to be visible after some months

High—probably due to oil, humidity, or static

High

Examples High grade offices, not near production; laboratories; clean rooms

High grade offices, not near production; laboratories; clean rooms

Mill offices; paper processing; light machining

Heat treating; high speed printing; rubber processing

Similar to Dirty but luminaires within immediate area of contamination

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8.1.3 Indoor Lighting Calculations. The design of lighting systems requires knowledge of basic lighting terms combined with simple mathematical or graphical presentation and techniques. The methods and calculations in the lighting design system presented in this Chapter are based on the recommended procedures of the Illuminating Engineering Society (IES) of North America. The formulas presented are only meant to be a general overview on the design calculation. In indoor lighting calculations, the luminaires are installed in an enclosed space or area. The calculations consider not only the light reaching the work plane (an imaginary horizontal plane at the height at which the task will be performed assumed to be 0.75 meter) directly from the luminaires but light reflected from the room surfaces as well (Figure 8.3). The reflectances of the room surfaces are therefore important in indoor calculations and affect the coefficient of utilization and therefore the efficiency of lighting system.

Useful Light = Direct + Indirect Component

Figure 8.3 Indoor Lighting (a) The Lumen or Zonal Cavity Method is usually the method used in indoor lighting calculations. It is based on calculating the percentage

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of the luminous flux or light radiated from the lamp that falls within the area being lighted.

This method is used to design general overall lighting of the room. This method calculates the illuminance that represents the average of the values at all points over the entire work plane of the room. The lumen method applies a factor known as the coefficient of utilization (CU) to the total lumens emitted by the light source (lamp lumens) to arrive at the number of lumens delivered to the lighted area.

The lumen method is based on the definition of illuminance as

luminous flux per unit area: Illuminance (E) = Eq 8.1 Luminous Flux (∅)

area

Since the illuminance level applies to the work plane, and the work plane for general lighting covers the whole room:

E = Eq. 8.2 total lumarea of room

inous flux falling on the work plane

Now consider a room in which the lighting has already been installed. By noting the number of luminaires in the room and the number and type of lamps installed in each luminaire, the total lumens generated by the lamps can easily be calculated:

TILL = total lamps x initial lumens per lamp Eq. 8.3 Where: TILL = is the total initial lamp lumens

Not all these lamp lumens reach the work plane, as some are trapped within the luminaire and some are absorbed by the room surfaces. Before the illuminance at the work plane can be calculated, it is necessary to establish a factor that represents the ratio between the

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lumens reaching the work plane and the total lamp lumens. This factor is known as the coefficient of utilization (CU). Thus,

CU = Eq. 8.4 total lumtotal initial lam

ens falling on the work plane p lumens

(b) The Coefficient of Utilization represents the efficiency of the whole lighting system, including the luminaires and the space (room) in which they are installed. It does not include the efficiency (efficacy) of the light source itself. The coefficient of utilization depends on a number of factors,

(1) Type of luminaire. Its efficiency and distribution pattern and

type and light source used. (2) Reflectance of room surfaces. The higher the reflectance

factors of the ceilings, walls, and floors, the greater the percentage of the lamp lumens that will be redirected to the work plane. (See Figure 8.4)

Figure 8.4 Room Reflectances

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(3) Mounting height of the luminaire. The greater the height, the greater the area of the wall surfaces is illuminated, which in turn absorbs more of the lamp lumens.

(4) Area of the room. The larger the room, the greater the number

of luminaires required. The light distributed from each luminaire overlaps one another, helping to increase the overall lighting level.

(5) Proportions of room. A room maybe long and narrow or

square. A square room has a higher coefficient of utilization than a long narrow room, all factors being the same.

Typical dimensions of different room sizes:

Small room : width = height Medium room : width = 2x height Large room : width = 4x height

In determining and computing the coefficient of utilization, the effects of the luminaire mounting height, the room size and proportions, and the height of the work plane are taken into account. As shown in Figure 8.5, the cross section of a room is divided into three separate cavities.

Figure 8.5 Room Cavities

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The space between the ceiling and the luminaire plane is the ceiling cavity, the space between the luminaire plane and the work plane is the room cavity, and the space between the work plane and the floor is the floor cavity. The cavity ratios (CR) for these three cavities are determined by using the following formula:

CR = Eq. 8.5 w

5h x (room length + room width) room length x room idth

Room-cavity Ratio, RCR =

5hRC x (L + W) L x W

Ceiling-cavity Ratio, CCR = = RCR

5hCC x (L + W)L x W

hCChRC

Floor-cavity Ratio, FCR = = RCR

5hFC x (L + W)L x W

hFChRC

NOTE: For a given room, the cavity ratios are in direct proportion to their respective cavity heights. For the case where the luminaires are mounted on the surface of the ceiling or are recessed into the ceiling, the ceiling cavity ratio is zero. The room cavity ratio is also directly proportional to the height of the room cavity (hRC), which is also the mounting height of the luminaire above the work plane. The greater the mounting height is, the greater value of the RCR factor (for the same width and length).

Since the coefficient of utilization is based on the room cavity ratio, it is necessary to treat this cavity as if there were a ceiling surface at the luminaire plane and a floor surface at the work plane level as shown in Figure 8.5. Therefore, it is necessary to convert the actual ceiling reflectance into an effective ceiling cavity reflectance (pCC). Similarly, the actual floor reflectance must be converted to an effective floor cavity reflectance (pFC).

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Combining the previous relationships gives: E = Eq. 8.6

TILL x CUArea

Where:

E = average illuminance at the work plane

From the time that a new lighting system is first used, the lighting level gradually decreases because of aging. The recommended lighting levels are based on minimum values that should be maintained over the operating life of the system. Therefore, it is necessary to provide higher initial illuminance levels to compensate for the loss of light with time.

Hence, the Light Lost Factor (LLF) equation is:

LLF = LLD x LDD x RSDD x BF Eq. 8.7

With reference to Eq. 8.6, the illuminance E in that relationship represents the initial value, that is, the lighting level when the system is first turned on. To include the light loss factor, the equation expands to:

E = Eq. 8.8

TILL x CU x LLF Area

Where E is the minimum average illuminance at the work plane just before corrective action is taken. (c) Calculation of Number of Luminaires. In Eq. 8.3, the assumption made is that the lighting system already exists and Eq. 8.6 and Eq. 8.8 therefore will give the illuminance level for that lighting system. However, this is not the situation for most lighting

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layout problems. What is required is a method of calculating the number of luminaires that will be required to provide the recommended minimum levels of illuminance.

The relationship of Eq. 8.8 can be rearranged as follows:

TILL =

E x Area CU x LLF

where: TILL = the total initial lamp lumens required E = recommended minimum illuminance No. of luminaires = Eq. 8.9 TILL

no. of lamps x initial lumensper luminaire per lamp

The value of E used in Eq. 8.8 can only be a target value. The number of luminaires calculated using Eq 8.8 and 8.9 can therefore only be considered as the theoretical number required, as a practical layout may dictate an adjustment to this number. Examples of design for indoor lighting systems are provided in Appendix E.

8.2—BASIC OUTDOOR/EXTERIOR LIGHTING DESIGN Outdoor lighting (except those of roadway lighting) refers to the lighting of open level areas with luminaires mounted above grade, typically on poles or structures. Applications include open parking areas, walkways, bikeways, storage yards, and sport facilities. Exterior lighting calculations are very similar to interior calculations, except that no light reflectances from room surfaces are calculated. However, some technical factors have to be considered in designing and

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evaluating an exterior lighting system such as glare, visibility, color, illuminance, luminance, and brightness. Exterior lighting designers generally allow the user to aim the fixture (interior programs usually assume the fixture will be parallel to the floor). Factors involved in exterior lighting calculation include the following:

Plan dimensions of the of site to be studied/lighted Points on the site where illuminance is required Luminaire photometry Mounting heights, site locations, orientations, and tilt of luminaries Lumen output of the specified lamp Light loss factors due to lamp aging, ballast factor, and luminaire dirt accumulation

The most common form of exterior lighting analysis is the calculation of illuminance on horizontal and vertical planes. Horizontal planes usually are used for roadways, pathways, and parking lots, while vertical planes are typically used for sports fields and automobile display areas. 8.2.1 Point-by-point Method. It is frequently necessary to calculate illumination levels at specific points to determine the lighting uniformity and minimum values. The point-by-point method is also useful for selecting the light distribution of the luminaire to insure that there will be no hot spots.

This calculation method relies on the inverse square law, the cosine law and the photometric distribution of the luminaire. This method for determining lighting design is more accurate than the lumen method, but it is more complex.

The formula below is mainly used for exterior lighting. If several luminaires contribute to the illumination at a point, the resultant illumination is determined by totaling the contribution of each luminaire to the plane where the point is located. (Please see Figure 8.6.)

luminance pt. A cd(Cos θ) = D2

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luminance pt. A cd (Cos3 θ)

MH2=

Where: MH = mounting height, meters

cd = luminous intensity, candela D = distance of light source to pt. A, meters θ = angle of light from vertical, degrees

Figure 8.6 Components of Point-by-Point Method

8.2.2 Design Factors. This guideline sets out the factors that need to be taken into account when designing outdoor lighting systems. They are listed not necessarily in the order of importance, as follows: (a) Recommended Illumination Level. There are two important factors that have to be considered in an outdoor environment. They are surface luminance and source luminance. Surface luminance includes horizontal and vertical surfaces. Examples of lighted outdoor horizontal surfaces are roadways, bike path, sidewalks, and parking lots. Lighted vertical surfaces include people’s faces and bodies, building facades,

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signs, structures, statutes, and landscape features such as trees. Surface luminance adds interest and depth to an outdoor scene and can be necessary for good outdoor visibility and security. It is important to see the effect of lighting, not the source. Source luminance does not only involve the lamp but also the luminaire’s reflector, refractor, lens, or louver. In order to minimize glare, source luminance in the typical direction of view should be minimized. Typical viewing angles lie between 45° and 85°. Luminances from bollards, landscape lights, and floodlights should be low to attract minimal attentions.

There is a recommended illumination for each type of application. Refer to Appendix C: Levels of Illumination Currently Recommended.

(b) Classification of Luminaire Light Distribution. Proper distribution of the light flux from luminaires is one of the essential factors in outdoor area lighting. The light emanating from the luminaires is directionally controlled and proportioned in accordance with the requirements for seeing and visibility. Light distribution is generally designed for a typical range for conditions which include luminaire mounting height, transverse (overhang) location of the luminaires, longitudinal spacing of luminaires, widths of areas to be effectively lighted, arrangement of luminaires, percentage of lamp light directed toward the pavement and adjacent areas, and maintained efficiency of the system. Luminaire light distribution may be classified with respect to three criteria:

(1) Vertical light distribution. This describes how far the light

reaches along the length of the area parallel to it. Vertical light distributions are divided into three groups, short, medium, and long. Classification is based on the distance from the luminaire to where-the beam of maximum candlepower strikes the surface area.

(2) Lateral light distribution. The luminaire's transverse

(projection) light distribution (perpendicular to the area) can be considered as types I, II, III, IV and V as shown in Figure 8.7.

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Figure 8.7 Types of Lateral Light Distribution

(3) Photometric Distribution. This is classified according to the cutoff characteristics: full cutoff, cutoff, semicutoff, and noncutoff. These classifications show what the maximum intensity of the light is above 180° and above 90° as shown below. These categories should be taken into consideration when glare or spill light may be a concern. It is divided into four categories:

a. Full Cutoff. A luminaire’s light distribution is designated as

a full cutoff (Figure 8.8) when the candlepower per 1,000 lamp lumens does not numerically exceed 0 (0 %) at or above a vertical angle of 90° above nadir (horizontal) and 100 (10 %) at or above a vertical angle of 80° above nadir. This applies to any lateral angle around the luminaire.

Figure 8.8 Full Cutoff

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b. Cutoff. These fixtures (Figure 8.9) are designed to prevent

the horizontal dissipation of light, and minimize glare even in locations where there is little background light. For maximum brightness (uniformity ratio of illuminance) the area lights must be spaced close together. A luminaire light distribution is designated as cutoff when the candlepower per 1000 lamp lumens does not numerically exceed 25 (2.5%) at an angle of 90° above nadir (horizontal), and 10% at a vertical angle of 80° above nadir. This applies to any lateral angle around the luminaire.

Figure 8.9 Cutoff

c. Semi-Cutoff. These fixtures (Figure 8.10) are designed to

spread light laterally as much as possible while at the same time restricting the amount of horizontal light. This is currently the most widely used fixture for general street lighting. A luminaire light distribution is designated as semi-cutoff when the candlepower per 1000 lamp lumens does not numerically exceed 50 (5%) at an angle of 90° above nadir (horizontal), and 20% at a vertical angle of 80° above nadir. This applies to any lateral angle around the luminaire.

d. Non-Cutoff. These fixtures (Figure 8.11) are designed to

not restrict horizontal light. They can be used in locations where the surroundings are bright, such as when there are many nearby buildings that also give off much light, or when bright and glittering illumination is desired. The category

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when there is no candlepower limitation in the zone above maximum candlepower.

Figure 8.10 Semi-Cutoff

Figure 8.11 Non-Cutoff

(c) Working Voltage. It is important that the systems voltage be checked. A voltage drop of 5% is allowable. (d) Aesthetics. It should be observed that the lighting system is only used during dark periods, but the installation must also be aesthetically acceptable.

(e) Maintenance Factor (MF). Light Loss Depreciation (LLD) and Luminaire Dirt Depreciation (LDD) are things that should be considered to establish the value of the maintenance factor. Values of maintenance factor may be found in the lighting and manufacturer’s catalogues.

Keeping the exterior lighting system performing at its designed level requires a considerable effort in maintenance. In order to endure

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weather conditions, exterior lighting equipment should be designed with enclosures and seals that may not be necessary in interior lighting equipment.

The mounting height and location of the exterior lighting equipment may make access difficult for maintenance purposes. In such conditions, group maintenance should be carefully programmed where lamps and luminaires in a system are replaced, cleaned, and inspected on scheduled interval. Such program should include luminaire cleaning and replacement of auxiliary equipment like lenses, gaskets, ballasts, ignitors, photocells and others.

In utmost condition, it is desirable to conduct component testing during routine maintenance and replace equipment as necessary. To maintain the minimum performance level and reduce frequent lamp burnouts, it is necessary to perform the regular scheduled maintenance religiously.

Aimed luminaires should be fixed and locked in its position so that in conducting maintenance it does not change the aiming position.

(f) Utilization Factor (UF). This is the percentage of rated lamp lumens which will fall on either of the two strip-like areas of infinite length, one extending in front of the luminaire and the other behind the luminaire when the luminaire is level and oriented over the area to be lighted in a manner equivalent to that in which it was tested. 8.2.3 Average Illuminance Equation. The general equation for the illuminance in a space is as follows:

x CU x LLF A ES =

φ (TOTAL)

S Where:

ES = average maintained illuminance on the surface area

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φ (TOTAL) = total system lamp lumen output, (lumen) CU = coefficient of utilization LLF = light loss factor AS = area of the surface, (m2)

8.2.4 Area Design Considerations

It is necessary to know or determine five items in the design of area lighting: size of area (width and length); pole spacing; pole height; luminaire type; and determination of the required number of lamps and luminaires. (a) Size of Area. By knowing the width and length of the area to be lighted, height and spacing of poles can be determined.

(b) Pole Spacing. The area that can be lighted by a single pole with reasonable uniformity is four times the mounting height (MH), or the light coverage is two times the MH on each side of a pole (Figure 8.12). When using more than one pole, spacing between poles should ideally be not more than four times MH (Figures 8.13 and 8.14). Closer spacing provides even better uniformity and fewer shadows. However, sometimes the arithmetic of specific area dimensions suggest that the 4 times spacing be exceeded slightly so as to avoid the expense of buying poles 1.5 meters higher. In no case should the spacing exceed 4.5 times the pole height.

Whenever possible, deviation from the average spacing shall not be more than 10%. Where spacing is not uniform, the average spacing shall be considered in the calculation of the illumination.

(c) Pole Height. Since the lighted area from each pole is 4 times MH, the 4x rule of thumb is used to determine pole height. Divide the width and length of area by 4x per pole when poles are inside the lighted area; or when at the perimeter of the lot, but not at the corners. (Figures 8.13 and 8.14). For 2 poles use 8x; 3 poles use 12x; and so on and so forth. When poles are at the corners of a lot, use 4x for each space between poles.

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Figure 8.12 Light Projection

Figure 8.13 Interior Poles

Figure 8.14 Perimeter Poles

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In situations where other pole attachments such as transformers,

capacitor banks, etc., affect the design mounting height, luminaires may be installed higher or lower depending upon the condition. Whenever possible, higher mounting height is preferable.

Example: Area 70 meters long, 30 meters wide

= 8.75 meters pole = 7.5 meters pole

One of the two choices can be made. Use a 9-meter pole or use 8-

meter pole on a 0.75 meter concrete base. From a cost standpoint, use the 8- meter pole. Fixture mounting height is 8.75 meters. Spacing to mounting height is very close to 4x down the length of the lot.

Best solution: 8 m pole on 0.75 base for MH of 8.75 m. Table 8.3 shows the suggested mounting height of luminaries for a particular lamp wattage.

Table 8.3 Suggested Mounting Heights

Lamp Wattage, W Mounting Height, m

70 to 175 250 400

1,000

4.5 to 6 6 to 7.6

7.6 to 18 18 to 30

70 m

17.5 m 17.5 m30 m

15 m

35 m

70m 30m 8 4

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(d) Luminaire Type. Luminaires or fixtures can be divided into two

categories. The first category is fixed aiming. These are mounted on a pole or wall and produce a specific pattern of light that cannot be changed or can be changed only slightly by moving the lamp position within the reflector. These luminaires are usually aimed straight down. They have their highest utilization when they are installed within the area they are lighting. Street lighting, parking lots, and high-mast area luminaires fall in this category.

Floodlights are the second category. These can be aimed. Floodlights

are available in a number of beam spreads (see Figure 8.9 Types of Lateral Light Distribution). They can be mounted individually or in clusters to light a few hundred square meter or several hectares mounting from one direction. The aiming point for flood lightings is normally twice (2x) the mounting height. If the edge of the area being lighted is at a distance less than twice (2x) the mounting height, aim the center of the beam 2/3 of the distance to the edge.

Example:

Given: Mounting Height (MH) = 12 meters Distance to be lighted = 21 meters

Required: Aiming point

Solution:

Aiming Pt. = (2/3) x 21 m

= 14 m 8.2.5 Rule of Thumb Method. Below is the Rule of Thumb Method for determining the required number of lamps and luminaires needed, taking into consideration the light source desired for the particular application.

(1) Determining recommended illumination level. For the recommended outdoor light illuminance level, refer to Appendix C. Figure 8.15 shows the graph calculations for rule of thumb method.

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Figure 8.15 Graph–Calculations, Rule of Thumb Method

(2) From the above Figure, locate the desired illumination level on the left side of the graph and read across until it intersects dark diagonal line representing the light source choice.

(3) Read straight down to the bottom scale of the graph to determine the watts/square m factor.

(4) Multiply the watts/square m by the total square meter of the area to obtain the total watts needed to light the area: Total watts = area (l x w) x watts/sq. meter (5) Divide the total watts by the desired lamp watts to obtain the total number of lamps and luminaires required.

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8.3 OBTRUSIVE (STRAY) LIGHTING

The Commission Internationale de I’Eclairage (International Commission on Illumination) defined obtrusive light as “unwanted light, which because of quantitative, directional, or spectral attributes, in a given context, gives rise to annoyance, discomfort, distraction, or a reduction in the ability to see essential information.”

The objectionable lighting problems such as sky glow, light trespass, and glare are not only associated with roadway lighting but also other outdoor installations including billboards. Designers should address these issues and promote energy efficient and good lighting practices whenever possible. Misdirected or misapplied outdoor lighting is a concern for aesthetic, environmental and energy management reasons. This Chapter identifies some of the issues and suggests lighting design solutions. The impact of obtrusive lighting upon human, animal or plant life is outside the scope of this Section, but should not be ignored by designers and engineers responsible for outdoor lighting. 8.3.1 Stray Lighting An important issue that the outdoor lighting designer must be concerned with is stray lighting caused by glare, light trespass and urban sky glow. This means that the solution to a significant part of the problem is in the hands of the lighting designer.

8.3.1.1 Sky Glow. Sky glow is the term used to describe the added sky brightness caused by the scattering of electric light into the atmosphere, particularly from outdoor lighting in urban areas.

This phenomenon is of concern to astronomers and to a lesser extent,

the general public who like to see the moon and stars, or just wish to enjoy the natural nighttime environment.

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Sky brightness is attributed to the following factors: urban/suburban growth; lighting designs that disregard glare calculations and precautions; inappropriate lighting equipment selection and installation.

8.3.1.2 Light Trespass. The term light trespass describes light that

strays from its intended target and illuminates adjacent properties. In outdoor lighting system design, light should fall basically around

the area to be illuminated. Light should not fall in places where it is not wanted such as residential areas (stray light entering their windows or intruding upon their property), annoying people. It may also interfere with the performance of various electronic security equipment (detectors and cameras).

An acceptable level of light trespass is typically 0.01-footcandle,

which is equivalent to moon light. Avoid using high masts fixtures close to residential areas, hospitals, hotels, and airports.

8.3.1.3 Glare. Glare is defined as when some portion of the emitting

or reflecting surface of the luminaire is directly observable by drivers, and the resulting illuminance at the eye of the driver results in either discomfort or disability glare. It reduces the ability of the driver to distinguish objects clearly. Discomfort glare is produced by most outdoor lighting equipment when it is observed against a dark background. 8.3.2 Mitigating Obstrusive Light

8.3.2.1 New Lighting Design. The least expensive and the most

successful approach to obtrusive light problems is prevention. The lighting design engineer should address this concern in the initial planning and construction phase.

8.3.2.2 Existing Lighting Design Installation. Remedial mitigation

is usually the most expensive approach, since it often involves replacing or modifying the existing installation of lighting equipment.

Some possible corrective measures include:

(a) Changing the existing luminaire to one with a different light distribution. The preferred luminaire will have no (or minimal) up-light

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component and reduced intensity in the direction of the residential area and adjacent environment. (b) Relocating pole(s) and luminaire(s) to less offending location(s). (c) Installing external light shield(s) on luminaire(s). While this is the least expensive alternative, it is not the most effective. Care must be taken to secure the shields to the luminaires so as not to create a maintenance problem. (d) Combining timers with dimmers so that outdoor lights can be dimmed (at certain times) to the minimum levels needed, reducing the impact of stray light.

8.4—COMPUTER AIDED LIGHTING DESIGN SOFTWARES A wide variety of computer programs are available from lighting manufacturers to perform interior and exterior lighting calculations. Some programs are very simple, while others are complex and can even interface with computer-aided design. The following is a list of some of the software packages available at the time of this printing. These software packages are not intended as a substitute for creating design but as an aid to the design process.

(a) General Electric Philippines • A GE Lighting Application Design and Analysis

(ALADAN) • EUROPIC

(b) OSRAM Philippines • DiaLux • Light@work

(c) Philips Lighting and Electronics • CalcuLux

(d) FUMACO Incorporated • RELUX 1 (Version 2.4 and 3.0) • DiaLux

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Chapter 9. Lighting System Maintenance

9.1—LIGHTING MAINTENANCE Proper lighting maintenance is essential to high quality and efficient lighting. Systematic lighting management methods and services from lighting specialists can help organize the process and assure continued high performance of any lighting system. Lighting maintenance is more than simply replacing lamps and ballasts when they fail. Facility managers today must manage their lighting resources (i.e., fixtures, lamp/ballast inventory, labor, energy) to sustain the quality of a lighting system. The light output of a luminaire decreases with age and use, and the energy input may increase over time. Because the human eye is extremely adaptive to gradually changing lighting conditions, most occupants do not notice the gradual decline in light levels. Eventually, however, the reduction will affect the appearance of the space and the productivity and safety of the occupants. In the past, lighting designers have dealt with this problem by increasing the number of fixtures or lamps to compensate for the future light loss. While this simplifies maintenance, it is not an acceptable solution due to the added initial equipment cost, energy cost, and energy-related pollution. 9.1.1 Maintenance Action Checklist

(a) Group relamp to reduce lumen depreciation and maintenance

costs. (b) Clean fixtures at time of relamping, more often in dirty locations.

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(c) Write a lighting maintenance policy. (d) Design lighting upgrade projects to incorporate effective

maintenance (e) Get help when needed from the following resources.

(1) lighting management companies (2) consultants (3) distributors (4) manufacturers

9.2—MAINTAINING LIGHT LEVEL

9.2.1 Group Relamping. In group relamping, all lamps are replaced just prior to the time in their rated life when burnouts begin to occur and lamps are greatly depreciated in light output. This is done to ensure lighting levels are maintained.

(a) Record and evaluate the lighting level in all areas, especially

after all new lamps are in place. (b) Conduct periodic light output checks with a lux meter to monitor

change in light levels. 9.2.2 Cleaning. Even in areas where air is well filtered, enough dirt accumulates on lamps, lenses or louvers and reflectors to reduce light significantly. Below are tips for cleaning fixtures:

(a) Clean lighting fixtures whenever lamps are replaced. (b) In areas where doors allow outside air or filtering is not

adequate, clean at least twice a year. (c) Wipe plastic lenses with damp, not dry cloth (a mild detergent

may be needed). (d) Small cell louver panels, including parabolic wedge louvers,

should be removed and dipped in mild detergent solution, then air-dried. (e) Do not wipe luminaire or lamps while fixture is energized.

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9.2.3 Spot Relamping. In spot relamping, lamps are replaced when it ceases operation unexpectedly or fails to light up after turning it on. Relamp immediately when lamp fails to light up to avoid damage to ballasts. 9.2.4 Advantage of Group Relamping and Cleaning

(a) Saves money, time, and energy (b) Improves overall system efficiency (c) Reduces maintenance time and costs (d) Efficiently utilizes maintenance personnel (e) Reduces lamp and ballast inventory (f) Reduces material costs through bulk purchasing practices (g) Provides higher maintained light level (h) Prevents unnecessary ballast degradation caused by ballasts trying to start expired lamps

9.3—MAINTENANCE PLANNING Many maintenance managers are hesitant to replace lamps that are still operating. But group relamping and cleaning can be less expensive than sporadic spot maintenance. Through strategic planning and performance management of the overall lighting system, costs can be reduced and lighting quality improved. Below are different steps in maintenance planning: Step 1: Define Existing Condition. The first step in planning a lighting maintenance strategy is to define the existing condition of the lighting systems. Evaluate the following:

(a) type of lamps and ballasts in use (b) average age of the lamps/ballasts (c) total annual hours of lighting operation (d) product costs (e) spot replacement labor costs (f) group replacement labor costs (g) energy costs (h) the rate of dirt accumulation

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Step 2: Establish a Relamping Interval. Identify an appropriate time to group the relamping of lighting system. First, you must determine an acceptable level of light loss and an acceptable number of lamp failures (or spot replacements). Step 3: Predict Light Loss Factor. With the above information, it is possible to evaluate existing and future light loss. The mortality, lumen depreciation, and dirt depreciation curves are used to determine the maintained illumination, which is the average illumination expected over time. An overall light loss factor is applied to initial illumination value to obtain the maintained illumination value. The formula for light loss factor (LLF) is discussed in Chapter 8. Step 4: Develop a Maintenance Method. There are several factors to consider when planning a lighting maintenance strategy.

(a) Use existing staff, hire new staff, or use a contractor. (b) Complete during regular hours, nights, or weekends. (c) Manage quality control. (d) Dispose of lamps and ballasts responsibly. (e) Re-lamp building-wide or in zones. (f) Establish product types. (g) Establish testing procedures for different types of lamps.

Step 5: Budget for Maintenance. Budgeting is the most difficult part of planning a maintenance program. Spot maintenance of a lighting system can be sporadic on a daily basis, but the annual cost will be constant after the first few years. Strategic maintenance on the other hand is easier to manage on daily basis and may cost less overall, but the cost fluctuates each year. Because budgets are often established a year in advance, it is necessary to predict relamp timing and budget accordingly. As an alternative, completing an equal portion of the group maintenance each year can level lighting maintenance budgets. Step 6: Write a Lighting Maintenance Policy. For a lighting maintenance program to be most effective, it needs to be carried out

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regularly over the life of the lighting system. You can write a lighting maintenance policy once you have completed a lighting management analysis, developed a method, and established a budget. This will help in getting the program approved and will enable the plan to be carried out by other personnel in the future or in other facilities. Include justification for the maintenance plan, so that future managers can understand the importance of effective maintenance. Most important, it will assure a systematic continuation of the program. Step 7: Implement the Strategy. A well-planned strategy can be easy to implement. Many companies use outside contractors to complete major tasks and then use inside staff to provide spot maintenance. Others contract with an outside lighting or electrical company to completely manage the lighting system. Similarly, an outside company can designate and train a lighting management team within the company. Whichever method you select, strategic lighting maintenance is a predictable task and reduces unscheduled maintenance requirements. Step 8: Getting Help. As the demand for planned lighting maintenance has increased, so have the services offered by the lighting industry. The following are some resources available to help analyze, plan, and implement efficient lighting maintenance.

(a) Lamp Manufacturers. Although strategic lighting management

can save energy and labor costs, group maintenance will usually require the use of more lamps. As a result, lamp manufacturers have an interest in providing assistance in analyzing lighting management strategies. Most of the assistance is valuable and reliable and offered free (or at low cost). Contact your lamp supplier or manufacturer for information. Assistance from lamp manufacturers is available from several sources.

(1) local factory representatives (2) distributors (3) software tools (4) training programs

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(b) Energy Service Companies (ESCOs). Energy Service

Companies (ESCOs) are maintenance or electrical contractors who offer energy savings solutions and services. Some specialize in lighting installations, upgrade, management, and maintenance. Many offer free, low cost or saving sharing schemes for the service to identify optimum lighting retrofits and maintenance programs. Some ESCOs may offer consulting services to help develop in-house lighting management programs, but most are interested in providing upgrade installation and maintenance contract services.

9.4 —TROUBLESHOOTING AND MAINTENANCE TIPS

Planned lighting maintenance entails more than simply changing lamps and cleaning. It is also an opportunity to efficiently locate and repair defective or broken components causing system problems. See chapter 5 on Light Systems for diagrams and explanations of the circuits described in this section.

9.4.1 Preheat Fluorescent Lamp Circuits

Troubleshooting

1. Replace existing lamps with lamps known to be operative. 2. Use only lamp types that are listed on the ballast label. Check to

make certain lamps can be used on preheat circuits. 3. Replace existing starters with starters known to be operative and

of proper rating, if changing to electronic ballast is not possible. 4. Check luminaire wiring for incorrect connections, loose

connections or broken lampholders or wires. Refer to the wiring diagram printed on the ballast.

5. Check the ballast to see if the label agrees with the application, with regard to temperature limitations and lamps. Replace the ballast if faulty or inappropriate. Always change to an appropriate electronic ballast when you must change ballasts.

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Maintenance Hints

1. Deactivated lamps should be replaced as quickly as possible. Cycling lamps cause abnormal currents to flow in the ballast, which will cause ballast heating and thereby reduce ballast life.

2. Lamp cycling will also reduce starter life. 9.4.2 Rapid-Start Fluorescent Lamp Circuits Constant heater current is essential for proper starting of all rapid-start lamps. It is also essential for proper lamp operation. Troubleshooting

1. If a lamp requires 5-6 seconds to start, one electrode may not be receiving the cathode heating current. This usually results in excessive darkening of that end of the lamp, which is visible after a short period of operation. With lamps removed from the sockets, check heater voltages. This can be done with available testers, which have a flashlight lamp mounted on a fluorescent lamp base. If a voltmeter is used, a 10-Ω, 10-W resistor should be inserted in parallel with the meter. The meter should measure at least 3 V. If proper voltage is found, check for poor contact between lamp holder and base pins or contacts on the lamp. Also check for proper spacing of lamp holders. If no voltage is measured, check for open circuit caused by poor or improper connections, broken or grounded wires, or open heater circuit of the ballast. Verify that the wiring conforms exactly to the ballast label diagram.

2. If one lamp is out and the other lamp is operating at low brightness or if both lamps are out, only one lamp may have failed. Note that two-lamp magnetic and some electronic circuits are of a series design.

3. Replace the ballast if the output voltage is not within its rated voltage, or if no voltage is present after determining that the input voltage to the ballast is correct.

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Maintenance Hints

1. Failed lamps should be replaced as quickly as possible. Rapid-start lamps require both heater current and starting voltage for proper operation. If either is missing, poor starting or short lamp life will result. In a two-lamp series circuit, one lamp can fail and the second lamp will operate at reduced current. This condition will reduce the life of the second lamp.

2. Lamps should be kept reasonably clean. All rapid-start lamps are coated with a silicone to provide reliable starting in conditions of high humidity. However, dirt can collect on the lamp surface and then absorb moisture when the humidity is high, thus nullifying the silicone coating and making the starting unreliable.

9.4.3 Instant-Start Fluorescent Lamp Circuits Two-lamp circuits can be of either lead-lag or series-sequence design. Lead-lag ballasts operate lamps in a parallel circuit meaning that if one lamp fails, the other should continue to operate properly. Series-sequence ballasts operate lamps in series, meaning that if one lamp fails, the other will fail or glow dimly. Troubleshooting

1. Replace existing lamps with lamps known to be operative. 2. Check lampholders for broken or burned contacts or discolored

plastic in the holders, indicating high temperature. Check circuit for improper or broken wires. Refer to the wiring diagram on the ballast.

3. If the ballast is suspected of being defective, replace it with one known to be operative. Measurement of output ballast voltages in the luminaire is difficult because the primary circuit of the ballast is automatically disconnected when a lamp is removed. If the ballast must be changed, always upgrade the fixture to an appropriate type of electronic ballast.

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Maintenance Hints

1. Deactivated lamps should be replaced as soon as possible. In a two-lamp series magnetic circuit, one lamp can fail and the second lamp will operate at low brightness. This condition will reduce the life of the second lamp and also will cause all abnormal current to flow in the ballast, giving rise to ballast heating and a reduction in ballast life.

2. Flickering instant-start or "slimline" lamps, which show heavy end blackening, should be replaced, even if the lamps are lighted. This condition is known as lamp rectification and will cause reduced ballast life if it is allowed to persist.

9.4.4 Mercury Lamps. (Note: Whenever possible, use HPS or Metal Halide, for better efficiency) Troubleshooting

1. Replace the lamp with one known to be operative. Be sure the

operative lamp is at room temperature, as hot lamps will not restart immediately.

2. Check that the lamp is properly seated and that its base eyelet and shell make proper contact in the lampholder.

3. Check the ballast nameplate. Make sure that ballast and lamp designations match. Refer to the system of lamp and ballast designations developed by the lamp industry and IEC or American National Standards Institute (ANSI).

4. Check the ballast wiring. If a multiple-tapped primary-winding ballast is used, be sure the connected tap matches the supply voltage.

5. Check the supply circuit wiring for open circuit or incorrect connections.

6. Replace the ballast if no output voltage can be obtained and make sure that line voltage is properly connected to the ballast input terminals. If you must replace the ballast, it would be better to retrofit the fixture to a more efficient HPS or Metal Halide equivalent, by changing the ballast and lamp (plus ignitor and capacitor, as required).

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7. If a lamp fails prematurely, especially if it does so repeatedly in the same way in the same luminaires check for the following:

a. Cracks or breaks in the bulb will allow air to enter the lamp

and cause arc tube shell failure. This can be caused by rough handling, by contact with metal surfaces of a bulb changer tool or metal parts of the luminaire, or by water droplets falling on an operating lamp.

b. Overly blackened or swollen arc tubes may indicate excessive lamp Current and over-wattage operation. See items 3, 4 and 5 above. Also, the ballast may have failed due to a component failure, Such as a shorted capacitor or core winding.

If the power is lost in an HID ballast-lamp combination for even a few cycles, the lamp will extinguish itself and then have to cool down somewhat, re-ignite, and warm up again before reaching maximum light output.

Caution: To prevent electric shock hazard, always turn off the power before removing or installing lamps. This is especially important when removing lamps that may have cracked or broken outer envelopes. Unless the power is turned off, the exposed metal parts of the internal lamp structure will be connected to power and touching them will cause an electric shock. Always follow safety guidelines. Maintenance Hints

1. If multiple-tapped ballasts are used, check to be sure that the tap

matches the supply voltage to which the ballast tap is connected. Connecting a given line voltage to a tap marked for a higher voltage will give low light output due to under-wattage operation. Connecting it to a tap marked for a lower voltage will cause, poor lamp lumen maintenance and short lamp and ballast life due to over-wattage operation.

2. The line voltage should be reasonably free of voltage fluctuations. A variety of ballast types are available that provide

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an appropriate percentage of lamp wattage regulation with respect to the percentage of line voltage variation.

3. Lamp-and-ballast combinations must be chosen so that their electrical characteristics match. This can be assured by following the system of lamp and ballast designations developed by the lamp industry and IEC or ANSI. Incorrect matching of lamp and ballast may result in short life and equipment damage.

4. Lamps should be handled carefully. Rough handling can cause scratches or cracks in outer glass envelopes, resulting in short lamp life and possible injury.

Caution: If the outer envelope of a lamp is broken or punctured, the arc tube will continue to burn for many hours. Turn off the power and replace the lamp immediately. Certain types of lamps are available that will automatically extinguish if the outer envelope is broken or punctured.

9.4.5 Metal Halide Lamps Follow the recommendations and all cautionary measures given for mercury lamps, as these also apply to metal halide lamps. The following additional information is also pertinent. Troubleshooting

1. Many metal halide lamps are to be used only in specified operating positions. Short life and improper light and color Output will result if this is not done.

2. The time to restart automatically after a short power interruption may be much longer than for mercury lamps. This is not a lamp defect or a cause for lamp replacement.

3. It is normal for metal halide lamps to have a short delay between the time that circuit is energized and the time the lamp starts.

4. Slight color shifts from lamp to lamp are characteristic of some metal halide lamps. Also, one to two days of' burning in an installation may be required to stabilize the color of a lamp and the uniformity among a group of lamps.

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Caution: Follow lamp manufacturers' recommendations with respect to allowed use of metal halide lamps in open or enclosed luminaires.

Maintenance Hints

1. If a metal halide lamp is to be moved from one luminaire to another, keep it in the orientation in which it was installed while transferring it. If the lamp is rotated, its color will take time to restabilize.

2. Operate metal halide lamps only in their allowed operating positions.

9.4.6 High-Pressure Sodium Lamps Troubleshooting

1. Follow steps 1 through 6 listed for mercury lamps. 2. If lamps fail prematurely, especially if' they do so repeatedly in

the same way or in the same luminaire, check the following: a. Same as item 7 of 9.4.4 Mercury Lamps b. Excessive discoloration of the arc tube or a metallic deposit

on the inside walls of the outer envelope may indicate over wattage operation. See items 3, 4 and 5 under Mercury Lamps. Also, ballast components may have failed; for example, a capacitor or the core winding may be shorted.

3. A high-pressure sodium lamp must be started with an igniter. If

both the old and a known good lamp fail to start, steps must be taken to determine if the igniter or the ballast or perhaps both are defective. First make certain that the proper line voltage is correctly connected to the ballast input. Obtain a ballast tester (a flashlight lamp mounted on a fluorescent lamp base) or voltmeter and follow the manufacturer's instructions to determine the defect.

Caution: Do not connect a voltmeter or multimeter to an open or inoperative high-pressure sodium socket. The high-voltage pulse from the igniter will damage the meter

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Maintenance Hints

1. Follow steps 1 through 4 for mercury lamps. 2. High-pressure sodium lamps have a vacuum in the space

between the ceramic arc tube and the outer envelope. Handle these lamps carefully, since vacuum lamps are known to make an inordinately loud noise if the glass should break when dropped.

3. In case the outer envelope breaks during lamp operation, ultraviolet emission is not a problem.

Caution: To prevent electric shock, always turn off the power before removing or installing lamps. This is especially important when removing lamps that may have cracked or broken outer envelopes. Unless the power is turned off, the exposed metal parts of the internal lamp structure will be live, and touching them will cause an electric shock.

9.4.7 Low-pressure Sodium Lamps Troubleshooting

1. Replace lamp with a lamp known to be operative. 2. Check the lampholder for proper seating of the lamp and for

proper contact. 3. Check the ballast nameplate reading for compatibility. 4. Check the ballast wiring. If a multiple-tapped ballast is used, be

sure the ballast tap matches the supply voltage at the ballast. 5. Check the circuit wiring for open circuit or incorrect

connections. 6. Check the grounding of the luminaires. 7. Replace the ballast. 8. If lamps fail prematurely, check for the following:

a. Lamp breakage. Check lamps for cracks or scratches in the

outer bulb. These can be caused by rough handling, by contact with metal surfaces in the bulb changer or luminaire, or by moisture falling on an overheated bulb

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b. Bulb touching the luminaire, the lampholder or any other hard surface.

9. If the arc tube is cracked, blackened or swollen early in life, or if

the connecting leads inside the outer bulb are damaged, check for the following: a. Over wattage operation. Check the ballast rating, the voltage

at the ballast and whether the proper tap on the ballast is being used.

b. Excessive current. Check if the ballast is shorted. Check for possible voltage surges or transients on the supply line.

Caution: Do not replace the bulb until the circuit is checked and the cause of the trouble has been corrected.

Maintenance Hints

1. If multiple-tapped ballasts are used, check to be sure the tap matches the supply voltage at the ballast. Low voltage will cause low light output, poor lumen maintenance and reduced lamp life. High voltage will cause short lamp life.

2. The circuit should be reasonably free from voltage fluctuations. Replacement ballasts should match the particular voltage, frequency and lamp type.

3. The proper lamp type should be used for the ballast in installation. Incorrect matching of lamp and ballast may result in short lamp life or lamps going on and off repeatedly.

5. Lamps should be handled carefully to avoid breakage.

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Chapter 10. Basic Lighting Energy Audit

INTRODUCTION As discussed in Chapter 1, Electric light sources are probably the most commonly used electrical equipment. Lighting is a principal user of electrical energy in commercial buildings, accounting for about 30% of commercial sector consumption. For buildings using newer lighting technology, lighting consumption can be reduced by approximately 20 to 40%. This represents a significant opportunity to save energy in commercial buildings and to reduce the environmental emissions that accompany the electrical power generation process. When attempting energy savings, lighting is probably the first place in a facility to look for savings because changes are usually easy, inexpensive and have a quick payback period. This information will help to determine the operating cost and the potential savings available from lighting efficiencies. This Chapter will provide basic concepts and information in conducting energy audit and survey and make recommendations that will result in both efficient and effective lighting systems. Audit detailed process and program and others will be not be covered by this Chapter.

10.1—DEFINITION A lighting audit is a detailed, systematic evaluation of the existing conditions of lighted spaces and the performance of lighting systems. The audit is characterized by detailed data collection, measurements, and an in-depth analysis of the data, usually performed by third-party lighting technical specialists.

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CHAPTER 10. BASIC LIGHTING ENERGY AUDIT

10.2—PURPOSE The main purpose of a lighting audit is:

(a) To gather information concerning the characteristics and the current condition of lighting systems and the lighted environment.

(b) To quantify the potential monetary savings and benefits for the

owner/occupants. (c) To determine if lighting upgrade is possible within the constraints

(time and budget) imposed by the building establishment owner or operator.

10.3—TYPES OF AUDIT The three basic types of surveys and audits are the walk-thru audit, the intermediate audit (mini-audit), and the comprehensive audit. These three types form a hierarchy from the simple walk-thru audit to the comprehensive audit, which is the most complex. The intermediate survey is used for those situations that are too complex for a walk-thru survey and too simple for a comprehensive audit. 10.3.1 The Walk-Thru Audit The walk-thru audit is the simplest type and is usually performed while the lighting technical specialists simply walks through a facility (hence the name). The intent of the walk-thru survey, the simplest type, is to collect just enough information in a short period of time to make effective recommendations. It is performed to gather quickly the most meaningful facts needed for a one-on-one retrofit. For the most basic walk-thru survey, no fixtures are counted and no calculation of power density is made. There is little analysis beyond simple payback, and a brief report describes the existing systems, outlines the proposed improvements, and reports the estimated payback.

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10.3.2 The Intermediate Audit or Preliminary Audit The intermediate is a hybrid of a walk-thru survey and comprehensive audit, containing elements of each. It is more detailed than a walk-thru survey, and the data collection is usually done by a small team of two or three lighting technical specialists. The financial analysis made for the intermediate audit usually is more than simple payback, but it still may not include a full-scale life-cycle costing procedure. Calculations are usually performed for the complete project instead of on a fixture or component basis. Reports usually include equipment inventories, power densities, limited evaluation of upgrade or relighting alternatives, and payback. 10.3.3 The Comprehensive Audit or Detailed Audit The comprehensive audit is performed when the highest level of detail is required and is usually conducted by small teams of two or three. At this level the auditor’s focus on visual tasks and the worker’s productivity as well as on lighting equipment is fully identified and counted, and a detailed evaluation of lighting quality improvements is outlined. An extensive analysis is performed, including life cycle costing. The need for collecting thorough equipment details is to provide multiple upgrade options or a relighting plan. To provide the detailed information required, all lighting equipment must be fully identified and counted. Attention will be paid to the actual mix of lamps and ballasts in use. A comprehensive report describes the condition of existing lighting systems and outlines several upgrade options, including relighting, with an analysis of each. Both positive and negative aspects of each measure considered should be reported so that the client can make an informed choice. Maintenance savings are calculated and reported, as well as the potential for productivity improvements. Ad description of the new look of the upgraded or relighted spaces may be included, supported by drawings or perhaps even rendered using a computer program with an advanced graphics package.

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10.4—THE LIGHTING SYSTEM AUDITOR A good lighting system auditor or evaluator should have experience in the field of energy efficiency with specialized experience in lighting energy audits and energy efficient lighting. Auditors shall possess good interpersonal and communication skills and also be skilled in interview techniques because some of the critical information for an audit must be obtained from interviews with key building personnel.

10.5—EVALUATING LIGHTING SYSTEMS To evaluate lighting systems means to examine or carefully appraise them. There are three (3) major steps in evaluating lighting systems:

(a) Performing a Lighting Audit. The characteristics of each lighting system need to be assessed, including operating conditions, operating hours, and maintenance.

(b) Identifying Opportunities for Improvements. Improvements

are the changes that raise the existing condition of the lighted environment to a more desirable condition or to a more excellent quality, that is, that make the lighted environment better. What to change and how to change will depend on the particular focus of the analyst and the objectives of the upgrade or relighting project.

(c) Calculating Savings and Potential Payback. Savings may be

calculated either as simple payback (SPB) or using life cycle costing (LCC). Different types of lighting system operating cost should also be considered before arriving at calculating the SPB and LCC. See Chapter 11 for sample calculations.

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10.6—MEASURING AND MONITORING EQUIPMENT REQUIREMENT

Below are the list of measuring and monitoring equipment required in the conduct of lighting system audit;

(a) Clamp-on Power Meter. Measures, computes and display circuit load at a given time (measurement taken at the circuit breaker and other circuit disconnecting means).

(b) Clamp-on Data Logger Power Meter. Automatically log and

interface to laptop computer the recorded data for power consumption over a period of time.

(c) True RMS AC Clamp Meter and Hybrid Recorder. Measure

flow of current in a conductor, capable of measuring power consumption, line voltage, insulation resistance in mega-ohm and temperature. It can measure electrical parameters without interrupting power utilization.

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(d) Energy Analyzer with Computer Interface. Records unit hour summary, peak/valley, demand summary and monitor phase angle. Automatic line monitoring is done thru connection of meter clamp.

(e) Flexible Transducer. Measure large ampere flow of current in a

conductor to monitor its total ampere flow (accessory to the clamp-meters).

(f) Lux Meter. Measure light illumination levels over the specific

area (workplane and room surroundings). (g) Two-way Radio. Use for fast communication and coordination

of activity during the conduct of audit especially for large area.

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(h) Binocular. Views nearer and closer readings to some far and elevated location of lighting system and installed meter and indicators in the site.

(i) Steel Tape and Roller Measure. Use to measure distances and

dimensions of rooms.

10.7—POTENTIAL OF ENERGY SAVINGS AND

PAYBACK PERIOD 10.7.1 Simple Payback (SPB)

SPB relates to how long it takes to recover an initial investment in a cost-saving measure, assuming the annual savings remain constant and the time value of money is unimportant. To calculate simple payback, simply divide the initial investment by the annual savings. 10.7.2 Life-Cycle Costing (LCC) LCC is an economic method of project evolutions that takes into account all costs arising from the ownership, operation, maintenance, and

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disposal of a lighting project. Instead of focusing on the short-term time to pay back that SPB does, LCC considers long-term economic performance. Life cycle cost is the total cost of owning, operating, maintaining, and disposing of a lighting system over a given period of time with all costs adjusted (discounted) to reflect the time value of money. 10.7.3 Lighting System Cost

(a) Lighting Energy Cost. Annual lighting energy cost is generally determined by multiplying annual kWh (energy consumption) by the cost per kWh.

(b) Replacement Lamp Cost. A lamp's rated life is the number of

hours, which elapse before half the lamps in a large group of lamps burn out. If lamps are left in place until they burn out, this can be determined by dividing the annual hours of use by the rated life of the lamp.

(c) Lamp Replacement Labor Cost. Determine lamp replacement

labor cost by multiplying the average number of new lamps installed each year by the time (in hours) required to install each. Then multiply the product by the hourly rate of the persons who install the replacement lamps.

(d) Ballast Replacement Cost. Most conventional ballasts last from

10 to 12 years. Determine the anticipated life of the types of ballasts installed, and divide it into the cost to effect a replacement (labor and materials included). Multiply the result by the number of ballasts (of each type of luminaire) installed.

(e) Maintenance Costs. Maintenance costs typically include the cost

of regular lamp and fixture cleaning. (f) Annual Operating and Maintenance Cost. The annual

operating and maintenance (O&M) cost of the system involved is the sum of energy cost, replacement lamp cost, lamp replacement labor cost, ballast replacement cost and other maintenance costs. The overall operating and maintenance costs are substantially more than the cost of energy alone.

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10.8—LIGHTING AUDIT REPORT

The layout and style of the Main Report is at the discretion of the Auditor. The report should be presented in a clear, concise and logical format. The report should include at minimum the following:

(a) Overview of the activities at the area audited (existing lighting systems) and the main energy end-users;

(b) Details of the scope of the Audit including the areas, systems and

activities assessed; (c) The status of the energy management system at the site audited; (d) The current energy performance of the site and of each of the energy

systems assessed in the Audit; (e) The recommendations should also match comprehensive

solutions to current task needs and provide flexibility for future needs (several upgrade options, including relighting, with a detailed analysis of each). The Auditor should confirm the technical feasibility of each recommendation.

(f) The Audit recommendations quantified in terms of energy savings

and payback period.

10.9—EXISTING LIGHTING SYSTEM CONDITIONS

To conduct a lighting audit you will first need basic lighting information, such as the number of lights, their location, and their time in use to help you understand the current energy use attributed to lighting in the facility. This information will help understand how much you are currently spending and the potential savings available from lighting efficiencies. Use the worksheet below to assess your current lighting conditions.

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The purpose of using this lighting system audit form is to ensure a consistent and systematic approach to and execution of a lighting audit. Note that not every parameter listed below will be relevant to every location/area.

Table 10.1 Existing Lighting System Conditions Assessment Worksheet

Name of Organization: Address: Contact Person: Tel no. / e-mail Address : Type of Audit Conducted : Date Audit Conducted : Name of Auditor/s :

1. Area and Location Audited : ___________________ 2. Dimensions of Area Audited : ___________________ 3. Visual task performed : ___________________ 4. Age of Person Performed the Task : ___________________ 5. Importance of Speed and Accuracy : ___________________ 6. Light Source 6.1 Location of Lamps : ___________________ 6.2 Type of Lamps : ___________________ 6.3 Number of Lamps : ___________________ 6.4 Lamp Wattage Rating : ___________________ 6.5 Mounting Height : ___________________ 7. Lamp ballast 7.1 Type of ballast : ___________________ 7.2 Number of lamps per

ballast : ___________________ 7.3 Watts per ballast : ___________________ 8. Type of Reflector : ___________________ 9. Type of Refractors : ___________________ 10. Surrounding Reflectances : ___________________

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11. Availability of daylight : ___________________ 12. Method of Control 12.1 Type Manual Switching : ___________________ 12.2 Type of Automatic

Switching : ___________________ 13. Light Level at Workplane : ___________________ 14. Area Light Power Density : ___________________

(W/m2) : ___________________ 15. Hours per week the fixture

in operation : ___________________ 16. Maintenance/Cleaning Schedule : ___________________ 17. Conditions of the space for

dirt depreciation : ___________________ 18. Safety and Security

Measures Required : ___________________ 19. Energy Consumption per month 20. Electricity cost per kilowatt hour

(kWh) : ___________________ 21. Electricity Demand Charges : ___________________ 22. Others (Observations/Comments)

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Chapter 11. Economic Analysis of Lighting

11.1—THE ROLE OF ECONOMIC ANALYSIS IN LIGHTING Economic Analysis in lighting must be viewed as a framework for which the requirement of the user can be properly taken into account. The decision to retrofit the lighting system should consider the economic needs of the owner. When the lighting of certain area fails to complement the architecture of the space, its rental value will not be achieved. Thus, a decision to retrofit the lighting system will be an economic decision. A lighting economic analysis for new or existing system should be as follows:

• Comparison of alternative system • Evaluation of maintenance techniques and procedures • Evaluation of energy management technologies and strategies • Determination of lighting effect on other building system • Budget plan and cash flow • Simplify lighting system characteristics to a cost measure • Determination of the lighting benefit relative to its cost (cost-

benefit analysis)

11.2—LIGHTING COST COMPARISONS Over the years, many techniques have been proposed for comparing the set of one lighting system against the other system. The method can be classified into two categories (see Table 11.1):

279

CHAPTER 11. ECONOMIC ANALYSIS OF LIGHTING

(a) First level analysis method, which neglect the time value of money.

(b) Second level analysis considers the time value of the money. The term time value of money refers to the depreciated value of money at a specified time in the future.

Table 11.1 Lighting Cost Comparison Methods

First-Level Analysis Methods* Second-Level Analysis Methods Cost of light Life-cycle cost-benefit analysis Simple payback Savings-investment ratio Simple rate of return Internal rate of return

*Generally not recommended for large or complex projects.

11.3—THE COST OF LIGHT The simplest cost analysis is by comparing the initial cost and other least expensive cost. Thus, if lamp A costs P60 and lamp B costs P50, lamp B is selected. If the lamps are identical in performance, the decision can be easily arrived. However, to attain certain benefit of light, both cost and benefits must enter into analysis for us to obtain a meaningful result. The idea of cost per unit lighting produced have been developed as basic measures of lighting. This cost of light will be expressed in pesos per million lumen hours. The cost of light can be expressed by the following equation: 1.0

Q = X Eq. 11.1

P + h L + WR

280


Where:

X = unit cost of a lamp (pesos/106lm x h), Q = mean lamp flux (thousand lumens), P = lamp price (pesos) h= labor cost to replace one lamp(pesos) L = average rated lamp life (thousand of hours), W = mean input power per lamp (including losses) (watts), R = energy cost (pesos/kilowatt-hour). Example: Two lamps that have identical light output (i. e., 3 000 lumens) except for their rated life. Lamp 1 has a rated life of 1000 hours, and lamp 2 has a rated life of 10000 ours. Using the cost of light for a lighting system with the following parameters:

Q = 3 000 lumens = 3 (1 000 lumens) P = P250.00 h = P250.00 L = 1 for lamp 1 (1 000 hours) L = 10 for lamp 2 (10 000 hours) W = 40 watts R = P10.00 per kilowatt-hour

X1 =

+ (40 x 10) 1.0 3.0

(P 250 + 250) 1

=

900 1 hrs

1.0 3.0

= P 300

Million lumen - hours

X2 =

+ (40 x 10) 1.0

3.0 (P 250 + 250)

10

281


=

+ (40 x 10) 1.0

3.0 500 10

= 450 3

= P 150

Million lumen hours Care should be exercised in using the above equation since it did not include luminaire, which housed the lamp. If a new efficient replacement lamp will be introduced by calculating Equation 1 twice, one for the existing lamp and the other for the new lamp, you could come up with the approximate cost to produce one million lumen hours with each of the two lamps individually. But, if they differed in physical size, shapes and operating temperature, efficiency of the luminaires, clearing requirements, intensity distribution, or maintenance characteristics, each one could affect the cost. Another setback of the cost-of-light method is that it does not consider the monetary depreciation. But if the project life is short (say, two years or less) or if it involves temporary lighting, the cost of the money may have little effect. Therefore, this method can still be useful.

11.4—SIMPLE PAYBACK Today, first-level method commonly used in lighting industry is the simple payback. This payback offer information on the amount of time required for an investment to be paid off. It is defined as initial cost divided by the annual cash saving:

P = Eq. 11.2

I A

Where: P = payback period (years), I = investment cost (pesos), A = annual saving (pesos).

282


Frequently asked question concerning the desirability of replacing existing lighting system with a new technology is “How long will the system pay for itself?”. For example, an office building may estimate that a lighting modification will save about Php100,000.00 in energy cost annually. The cost in purchasing and installing the modification is Php 500,000.00. Thus the simple payback period would be:

P = Php 500,000/ P 100,000 = 5 years

This is actually a risk assessment tool posing as a profitability metric. It cannot answer the investment is profitable. Rather, it responds to the concerns of the future and hopes to recoup the investment as soon as possible. The problem with this method is that, if the savings from system A (which has a shorter payback than system B) decrease sharply every year after the payback period while the savings of system B remain steady. The payback method will lead one to select an inferior alternative. Therefore, the payback method cannot be used when the alternatives have non-uniform savings. Like the cost-of-light method, simple payback is best suited for short-lived projects for which interest rates is not so important. But this can be helpful as an initial screening for projects with a payback period of within one to two years. However, a project that did not pass on this screening method should not be rejected, since it may still be profitable after more rigorous analysis based on a second-level method.

11.5—SIMPLE RATE OF RETURN The simple rate of return is simply the reciprocal of the payback:

ROR = x 100% Eq. 11.3 A I

Where:

ROR = rate of return, (%) A = annual savings (Pesos) I = investment cost (Pesos)

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Thus if the system saves Php1,000,000.00/yr and requires an initial investment of Php5,000,000.00 its simple rate of return is Php 1,000,000.00/Php5,000,000.00 or 20%, equivalent to a 5-year payback. The advantages and disadvantages of this method is identical to those of the payback method. It is simple to apply and understand, but it cannot deal with non-uniform savings stream or unequal lives.

11.6—LIFE-CYCLE COST-BENEFIT ANALYSIS (LCCBA) The first-level method is generally not recommended for large complex projects because they may lead to serious errors. The second-level method, Life-Cycle Cost-Benefit Analysis (LCCBA) is approved by the experts in managerial economics from all industries. LCCBA uses a differential costing. The time value of money is considered. An outline for comparing new interior lighting system is shown on Worksheet (Table 11.2). In the Worksheet, the two lighting system alternatives are compared. Both systems must be assumed to have equal functional benefits or requirements, and other additional benefits that do have economic value to the owner. The method can be expanded using the same format comparison of additional options.

Table 11.2 Worksheet for LCCBA

System 1 System 2

A. Initial Costs 1. Lighting system—initial installed

costs, all parts and labor: 2. Total power consumed in lighting

system (kW) (including ballast and transformer)

3. *Air-conditioning tons required to dissipate heat from Lighting (kW / 3.516):

4. First cost of air-conditioning tons in line A3 @ P/ ton:

5. Reduction in first cost of heating equipment (in negative number)

6. Utility rebates (enter financial incentive as a negative number)

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Table 11.2 (Continued) System 1 System 2

7. Other first costs cause by the presence of the lighting systems: (e.g. Insurance)

8. Subtotal mechanical and electrical installed cost: (A1+A4+A5+A6+A7) take note of sign

9. Initial taxes: 10. Total costs(A8+A9) 11. Installed cost per square meter

(memo only, not included in calculation):

12. Watts of lighting per square meter (memo only, not included in calculation):

13. Residual (salvage) value at end of economic life:(use negative value if money received for the salvage, positive if the cost incurred to dispose of the system at end of life)

B. Annual Power and Maintenance Costs 1. Luminaire energy

[operating hours x kW x (P/kWh)]: 2. *Air-conditioning energy

[operating hours x tons x kW/ton x (P/kWh)]:

3. Air-conditioning maintenance (tons from A3 x P/ton):

4. *Reduction in heating cost: 5. Reduced heating maintenance

(MBtu x P / MBtu): 6. Other annual costs produce by the

lighting system: 7. *Cost of lamps annually (see

notes): 8. *Cost of ballast replacement (see

notes): 9. Luminaire washing cost

(number of luminaires x cost per luminaire):

10. Annual insurance cost: 11. Annual property tax cost: 12. *Subtotal, annual power and

maintenance (with income tax):

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Table 11.2 (Continued) System 1 System 2

B. Annual Power and Maintenance Costs 13. *Income tax effect of depreciation:

C. Comparisons

1. *Present worth: A10 + P(A13) + P(B12 + B13)

2. *Annual cost: A(A10) + A(A13) + B12 + B13

In section C, P represents the present worth factor, and A represents the annual cost factor described in the text. 11.6.1 NOTES on the LCCBA Worksheet. Since the analysis of lighting system economics is predominantly cost analysis, the system used is that costs are positive and the revenues, savings and benefits are considered negative. The worksheet can be used to analyze new construction as well as lighting retrofits. For lighting retrofits, the existing system can be identified as System 1, each line item should reflect the associated costs. If the initial costs for the existing system are mostly zero, maintenance costs on the existing system should be considered. Proposed replacement cost for the system should consider the equipment being re-used (e.g., most of the existing electrical wiring). Input value should reflect the lamp/ballast/luminance combined performance and cost characteristic values. Section A

(A3) All lighting system will produce heat into the building, which should be dissipated by the air-conditioning system. One ton of air conditioning can dissipate the heat generated by 3.516 kW of lighting (equivalent to 12,000 Btu/h). If the lighting system choice alters the size of the air-conditioning equipment, the appropriate equipment size should be entered so that the difference in refrigeration tonnage will be

286


considered between alternate lighting conditions. If the air-conditioning equipment does not change, enter a zero on this line.

NOTE: Interior and exterior shading devices and glazing conditions

will affect the air conditioning load if daylight system is analyzed

Section B

(B2) The number of tons of air-conditioning should come from A3. it is approximately 1.25 kilowatts per ton.

(B4) This is the reduction in the annual cost of fuel for heating

equipment due to increased heat obtained from the lighting system. The number of heating hours can be obtained by the formula.

Heating hours = (lighting hours) x 0.85 – (cooling hours)

The heat from the lighting system in Mbtu is given by this formula:

Heat from lighting system:

= (kW of lighting) x (0.0034 Mbtu/kWh) x (heating hours) Annual reduction in heating energy costs:

: = (Mbtu of heat from lighting) x (fuel cost per Mbtu)

NOTE: Consideration should be given if daylighting is used specially as the effect of shading devices on air conditioning cost.

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Table 11.3 Conversion Factors for Various Fuels

Fuel

Fuel Efficiency

Unit Energy

Fuel to Obtain 1 Mbtu

Electric heat 1.0 0.0034 Mbtu/kWh 293 kWh Coal 0.65 30 Mbtu/ton 0.05 ton No. 2 fuel oil 0.70 0.14 Mbtu/gal 10 gal Natural gas 0.70 1.0 Mbtu/mCF 1.4 mCF/Mbtu

(B7) If spot relamping is used, then the lamp cost per year will be:

Lamp cost per year =

For group relamping, use:

Lamp cost per year = (cost/lamp of group relamping) X (number of lamp replaced/yr)

Either way, the number on this line should be peso amount.

(B8) To annualize ballast cost, use:

Ballast cost per year = (cost to replace one ballast) x (number of ballast in the system)

(cost for spot replacement of one lamp) x (no. of lamps in the system) (lamp life) / (annual burning hours)

(ballast life) / (annual burning hours) Where:

A = cost to replace one ballast, B = number of ballasts,

L = annual burning hours, (B12) (B1 + B2 + B3 + B4 + B5 + B6 + B7 + B8 + B9 + B10 + B11) x (1- ITR) ITR = income tax rate

288


(B13) Depreciation will reduce owner income tax liability. The annual depreciation is given by: Initial cost from A10 D = Economic life of system If a given tax rate (ITR) is expressed as a decimal fraction then tax effect is

T = D x ITR. This is entered as a negative value, since it is a saving.

Section C

(C1) A present-worth comparison is done by finding "time zero"

equivalents of all future costs and adding those to the initial costs of line A10. Eq. 11.5 is used to convert the residual value (A13).

(C2) An annual-cost comparison requires that all one-time costs (initial costs and residual values) be converted to annual equivalents. These are then added to the annual energy and maintenance costs. Use Eq. 11.6 to convert the initial cost of line A10 to its annual equivalent. The residual value (line A13) is converted to an annual value using Eq. 11.7. 11.6.2 Financial Equations After completing the Worksheet, the second step is to make all terms into the time equivalent to allow for comparison. The following equations are used to take the time value of money into consideration: The single present-worth factor is calculated as follows;

P = F x Eq.11.4 1

(1 + i)n

289


Where:

P = present worth, or the equivalent value at present (pesos), F = future worth, or the amount in the future (pesos),

n = number of years, i = opportunity or interest rate per annum as a decimal

fraction (e.g. 5% equals 0.05). In other words, one will be willing to spend P pesos now as to pay F pesos at time n years in the future. The uniform present-worth factor is determined by the following equation:

P = A x Eq.11.5 (1 + i)n - 1

i(1 + i)n

Where:

P = present worth, or the equivalent value at present (pesos), A = annual payment amount (pesos),


fraction. The equation converts annual amounts into a single present value. There is no difference between making annual payment of A pesos for the next n year and paying P pesos today. The uniform capital recovery factor is

A = P x Eq.11.6 i(1 + i)n

(1 + i)n - 1

Where: A = annual payment amount (pesos), P = present worth, or amount at present (pesos),


fraction .

290


This is the reciprocal of the uniform present-worth factor, the uniform capital recovery factor, is the annual amount which, in a uniform stream, is equivalent to P pesos today. The uniform sinking fund factor is determined by:

A = F x Eq. 11.7 i

(1 + i)n - 1

Where:

F = future worth or amount in the future (pesos), A = annual payment amount (pesos),


fraction . This equation is an equal stream of annual amounts that is equivalent to some specified amount at a specific time in the future. Again, there is no cost difference between the offer of F pesos at n years from now and the offer of A pesos each year for n years. The present worth of an escalating annual cost can be determined by one of several formulas. The general form is

P = ∑ A Eq. 11.8(a)

k(1 + r)(1 + i)k

k= 1

n

Where:

P = present worth, or amount at present time(pesos), A = initial annual payment, amount (pesos),

n = number of years, i = opportunity or interest rate per annum, r = rate of escalation, or percentage by which the annual

payment increase each year, as a decimal fraction.

291


If the initial interest rate, i, and the rate of escalation, r, are the same, the equation becomes,

P = An Eq. 11.8(b)

If i and r are different, Eq. 11.8(b) becomes;

P = A x Eq.11.8(c)

(1 + r) [(1 + i)n – (1 + r)n](1 – r)(1 + i)n

Where: P = present worth, or annual amount at present (pesos), A = initial annual payment, amount (pesos),

n = number of years, i = opportunity or interest rate per annum, r = rate of escalation, or percentage by which the annual

payment increase each year, as a decimal fraction (e.g. 5% equals 0.05).

The system comparison can be made either way. Either by the residual value (line A13 from Table 11.2) and annual costs (lines B12 and B13) which can be converted to their present values using Eqs. 11.4 and 11.5 respectively, or by the total initial cost (line A10 from Table 11.2) and the residual value (line A13), which can be converted to annualize amounts using Eqs. 11.6 and 11.7, respectively. Once all costs for a system have been converted to either annual equivalents or present-worth equivalents, they can be computed to obtain a single value for each system. Both systems can now be compared on the basis of a single number. These approaches are summarized in section C of Table 11.2. An additional condition can be injected if an estimate is available for the expected rate of cost increase over time for any of the costs (for example, if it is predicted that the cost of energy will increase 5% each year over the planning horizon). Using Eq 11.8 (a), (b), or (c), escalation

292


rates of this type can be applied to the annual costs of lines B1 through B11 of Table11.2. 11.6.3 Notes on the Use of Equations 11.4 through 11.8 Equations 11.4 through 11.8 imply that one peso today is not the same in value to one peso a year from now. This is easily seen from the example of Php 5,000.00 deposited that bears 5% annual interest. At the end of one year, the amount has grown to Php 5000.00 plus 5%, or Php 5250.00. Therefore, Php 5,000.00 today is in some sense equivalent to Php 5,250.00 one year from today. In terms of Eq 11.4;

P = F x 1 (1 + i)n

Php5,000 = Php5,250 x 1

(1 + 0.05)1 If we want to know how much should be deposited today in order to yield Php100,000 in 20 years after at an interest rate of 5%. Using Equation 11.4;

P = Php100,000 x 1

(1 + 0.05)20 = Php37,689 Again, Php37,689.00 today is equivalent to Php100,000.00 in 20 years with an interest rate of 5%. Similarly, if the depositor in the previous example does not have Php37,689.00 today to deposit how much money must be set aside each year over the next 20 years in order to have Php 100,000.00 on hand at the end of that period. Using Equation 11.7 ;

293


A = F x i

(1 + i)n - 1

= Php100,000 x 0.05 (1 + 0.05)20 - 1

= Php3,024 Twenty annual payments of Php3,024.00 are equivalent to Php 100,000.00 20 years from now, at 5% interest rate. One might be willing to put up Php3,024.00 annually in maintenance costs to avoid the need to replace a lighting system at a cost of Php100,000.00 after 20 years. To illustrate the use, of Eq. 11.5, consider a lighting retrofit that saves Php 10,000 .00 annually in energy costs over the next 10 years. How much should one be willing to pay for this retrofit today if the interest rate is 6%?

P = A x (1 + i)n - 1

i(1 + i)n

P = Php10,000 x (1 + 0.06)10 - 1

0.06(1 + 0.06)10 = Php73,601 So Php73,601 today is equivalent to a stream of equal payments (or receipts) of Php 10,000.00 annually for 10 years at 6% interest.

294

297

Appendix A. Checklist of Energy-Saving

Guidelines

Appendix A contains recommendations for the development of an

energy management program for new construction and existing spaces.

The list can be scanned quickly to determine which ideas may be

applicable for a particular installation. The designer should review these

guidelines in consultation with the client and consider those which meet

the needs of the client and occupants.

Lighting Needs

Visual tasks:

specification

Safety and esthetics

Over lighted

application

Groupings: similar

visual tasks

Task lighting

Luminance ratios

Identify specific visual tasks and

locations to determine recommended

illuminance for tasks and for

surrounding areas.

Review lighting requirements for given

applications to satisfy safety and

esthetic criteria.

In existing spaces, identify

applications where maintained

illumination is greater than

recommended. Reduce energy by

adjusting illuminance to meet

recommended levels.

Group visual tasks having the same

illuminance requirements, and avoid

widely separated workstations.

Illuminate work surfaces with

luminaires properly located in or on

furniture; provide lower ambient

levels.

Use wall washing and lighting of

decorative objects to balance

brightness’s.

APPENDIX A. CHECKLIST OF ENERGY-SAVING GUIDELINES

298

Space Design and Utilization

Space plan

Room surfaces

Space utilization:

branch circuit

wiring

Space utilization:

occupancy

When possible, arrange for occupants

working after hours to work in close

proximity to one another.

Use light colors for walls, floors,

ceilings and furniture to increase

utilization of light, and reduce

connected lighting power to achieve

required illuminance. Avoid glossy

finishes on room and work surfaces to

limit reflected glare.

Use modular branch circuit wiring to

allow for flexibility in moving,

relocating or adding luminaires to suit

changing space configurations.

Light building for occupied periods

only, and when required for security or

cleaning purposes (see chapter 31,

Lighting Controls).

Daylighting

Daylight

compensation

Daylight sensing

Daylight control

If daylighting can be used to replace

some electric lighting near fenestration

during substantial periods of the day,

lighting in those areas should be

circuited so that it may be controlled

manually or automatically by

switching or dimming.

Daylight sensors and dimming systems

can reduce electric lighting energy.

Maximize the effectiveness of existing

fenestration-shading controls (interior

and exterior) or replace with proper

devices or shielding media.


299

Space utilization Use daylighting in transition zones, in

lounge and recreational areas, and for

functions where the variation in color,

intensity and direction may be

desirable. Consider applications where

daylight can be utilized as ambient

lighting, supplemented by local task

lights.

Lighting Sources: Lamps and Ballasts

Source efficacy

Fluorescent lamps

Ballasts

HID

Incandescent

Compact fluorescent

Lamp wattage

reduced-wattage

lamps

Install lamps with the highest

efficacies to provide the desired light

source color and distribution

requirements.

Use T8 or T5 fluorescent and high-

wattage compact fluorescent systems

for improved source efficacy and color

quality.

Use electronic or energy efficient

ballasts with fluorescent lamps.

Use high-efficacy metal halide and

high-pressure sodium light sources for

exterior floodlighting.

Where incandescent sources are

necessary, use reflector halogen lamps

with IR recycling for increased

efficacy.

Use compact fluorescent lamps, where

possible, to replace incandescent

sources.

In existing spaces, use reduced-wattage

lamps where illuminance is too high

but luminaire locations must be

maintained for uniformity.


300

Control compatibility

System change

Caution: These lamps are not

recommended where the ambient space

temperature may fall below 16oC

(60oF).

If a control system is used, check

compatibility of lamps and ballasts

with the control device.

Substitute metal halide and high-

pressure sodium systems for existing

mercury vapor lighting systems.

Luminaires

Maintained

efficiency

Improved

maintenance

Luminaire efficiency

replacement or

relocation

Heat removal

Maintained

efficiency

Select luminaires which do not collect

dirt rapidly and which can be easily

cleaned.

Improved maintenance procedures may

enable a lighting system with reduced

wattage to provide adequate

illumination throughout system or

component life.

Check luminaire effectiveness for task

lighting and for overall efficiency; if

ineffective or inefficient, consider

replacement or relocation.

When luminaire temperatures exceed

optimal system operating temperatures,

consider using heat removal luminaires

to improve lamp performance and

reduce heat gain to the space. The

decrease in lamp temperature may,

however, actually increase power

consumption.

Select a lamp replacement schedule for

all light sources, to more accurately


301

predict light loss factors and possibly

decrease the number of luminaires

required.

Lighting Controls

Switching: local

control

Selective switching

Low-voltage

switching systems

Master control

system

Multipurpose spaces

"Tuning" illuminance

Scheduling

Install switches for local and

convenient control of lighting by

occupants. This should be in

combination with a building-wide

system to turn lights off when the

building is unoccupied.

Install selective switching of

luminaires according to groupings of

working tasks and different working

hours.

Use low-voltage switching systems to

obtain maximum switching capability.

Use a programmable low-voltage

master switching system for the entire

building to turn lights on and off

automatically as needed, with

overrides at individual areas.

Install multicircuit switching or preset

dimming controls to provide flexibility

when spaces are used for multiple

purposes and require different ranges

of illuminance for various activities.

Clearly label the control cover plates.

Use switching and dimming systems as

a means of adjusting illuminance for

variable lighting requirements.

Operate lighting according to a

predetermined schedule.


302

Occupancy / motion

sensors

Lumen maintenance

Ballast switching

Use occupancy / motion sensors for

unpredictable patterns of occupancy.

Fluorescent dimming systems may be

utilized to maintain illuminance

throughout lamp life, thereby saving

energy by compensating for lamp-

lumen depreciation and other light loss

factors.

Use multilevel ballasts and local

inboard-outboard lamp switching

where a reduction in illuminances is

sometimes desired.

Operation and Maintenance

Education

Parking

Custodial service

Reduced illuminance

Cleaning schedules

Analyze lighting used during working

and building cleaning periods, and

institute an education program to have

personnel turn off incandescent lamps

promptly when the space is not in use,

fluorescent lamps if the space will not

be used for 5 min or longer, and HID

lamps (mercury, metal halide, high-

pressure sodium) if the space will not

be used for 30 min or longer.

Restrict parking after hours to specific

lots so lighting can be reduced to

minimum-security requirements in

unused parking areas.

Schedule routine building cleaning

during occupied hours.

Reduce illuminance during building

cleaning periods.

Adjust cleaning schedules to minimize

time of operation, by concentrating

cleaning activities in fewer spaces at


303

Program evaluation

Cleaning and

maintenance

Regular system

checks

Renovation of

luminaires

Area maintenance

the same time and by turning off lights

in unoccupied areas.

Evaluate the present lighting

maintenance program, and revise it as

necessary to provide the most efficient

use of the lighting system.

Clean luminaires and replace lamps on

a regular maintenance schedule to

ensure proper illuminance levels are

maintained.

Check to see if all components are in

good working condition. Transmitting

or diffusing media should be

examined, and badly discolored or

deteriorated media replaced to improve

efficiency.

Replace outdated or damaged

luminaires with modern ones which

have good cleaning capabilities and

which use lamps with higher efficacy

and good lumen maintenance

characteristics.

Trim trees and bushes that may be

obstructing outdoor luminaire

distribution and creating unwanted

shadows.


304

305

Appendix B. Efficient Lighting Initiative

(ELI) Voluntary Technical Specification

1. Compact Fluorescent Lamps

Compact Fluorescent Lamp (CFL) should meet the performance

specifications below:

Laboratory and Test

Requirements

Performance Specifications

Laboratory Facility

Must be accredited according to ISO/IEC

17025 and qualified for pertinent lighting

product tests by a recognized national or

regional accreditation body. (See the ELI

Certification Protocol on the ELI website.)

A copy of the accreditation document

must be provided to ELI.

Testing Conditions

Performed at 25±1 °C in an international

standard atmosphere with maximum

relative humidity of 65%.

Position and Initial

Burn-in

Measurements should be recorded from

products in vertical base-up position, after

an initial burn-in period of 100 hours, at

stabilized light output and current.

Test Data and Sample

Size

The applicants shall submit a separate set

of test reports for each individual model.

The test reports for the lowest wattage

model in each certification unit as

described in 4.1 and 4.3 must be from

testing laboratories which meet the

conditions described above. For other

rated wattages in the same certification

unit, the test reports from non-accredited

testing laboratories are recognized.

Test data must be from the model for

which qualification is sought. Values

indicated on the Product Application

Form–Self-ballasted Compact Fluorescent

Lamps should be the testing data from the

samples tested. Measurements of

APPENDIX B. ELI VOLUNTARY TECHNICAL SPECIFICATION

306

photometric and electrical characteristics

must be submitted for 8 units of the same

model.

Longevity of Test

Results

Longevity of test results is two years,

unless the applicant can document to

ELI’s satisfaction that older test results

accurately portray the performance of the

present model.

Electrical

Characteristics


Electromagnetic and

Radio Frequency

Interference

Comply with CISPR 15 and relevant local

regulations.

Harmonic Comply with harmonic current limits set

by IEC 61000-3-2.

Power Factor Power factor shall be ≥ 0.5 at maximum

power.

Electromagnetic

Compatibility

Interference

Comply with IEC 61547 and all relevant

local regulations if available.

Transient Protection Comply with IEC 61547.

Operating

Characteristics


Operating Conditions The product package must declare the

operating temperature conditions.

In such conditions, with 92%~106% rated

voltage, the lamp can start reliably and

maintain stable operation.

Minimum Starting

Temperature

The product package must declare the

minimum starting temperature and any

other conditions (such as installation in an

enclosed luminaire) that would affect

either reliable starting or the starting

time.

Starting time CFL must continuously illuminate within

1.5 second of being switched on at

25±1oC and 92 % of rated voltage.

Lifetime Must have a minimum rated lifetime of

6,000 hours as defined in 3.11. Rated

lifetime should be clearly indicated in

hours on product packaging.


307

The full lifetime test shall be measured in

accordance with IEC 60969. The full

lifetime test results are allowed not to

accompany with the Product Application


Lamps. However, the full lifetime test

results shall officially be submitted upon

completion of the lifetime testing. ELI

reserves the right to withdraw the use of

the logo if the test results do not meet the

ELI specification, or require the applicants

to revise the rated lifetime indicated on the

product packaging if the actual full life

time testing results do not meet the

claimed rated lifetime.

Safety Must comply with IEC 60968 and relevant

local regulations.

Light Characteristics Performance Specifications

Correlated Color

Temperature

Must comply with IEC 60969 and the

color tolerance shall be within 5SDCM

from the target values.

Correlated color temperature (CCT) must

appear on the product packaging.

Color Rendering Index Color Rendering Index (CRI) should be at

least 80, as measured in accordance with

CIE13.3.

Lumen Maintenance The luminous flux of the lamp must be >

80% of initial levels at 40% rated of

model’s rated lifetime. Luminous flux

shall be measured according to IEC

60969.

Efficiency Specifications

Lamp wattage shall be classified based on the rated wattage, but the

test wattage shall be within ± 15% of rated wattage. Initial luminous

efficacy shall be calculated from initial luminous flux and input

power for the specific lamps measured at 25±1oC and at rated

voltage. Where the rated voltage is a range, then the test voltage

shall be: (a) the nominal voltage of the country/region of intended

use; or; (b) the mid point of test voltage shall be: (a) the nominal


308

voltage of the country/region of intended use; or; (b) the mid point of

efficacy (lm/W) of the lamps applying for ELI shall not be less than

the value indicated in the table.

Input

Power of

Lamp (W)

Initial Luminous Efficacy (lm/W)

Correlated Color Temperature (CCT)

6500K 5000K 4000K 3500K 3000K 2700K

≥ 5 to < 9 46 50

≥ 9 to < 15 52 55

≥ 15 to < 25 57 60

≥ 25 to ≤ 60 62 65

The minimum initial luminous efficacy of a lamp model with a cover

(no reflector) shall be no less than 85% of the requirements indicated

in the above table. Separate applications must be made for models

offered with a cover option.

The produce packaging must clearly state the performance of the

following characteristics:

Rated power in watts, and

Rated operating voltage, and

Light output in lumens (luminous flux).

Other Specifications

Requirements Specifications

Label and Comparison

of Self-ballasted

Compact Fluorescent

Lamps to General

Lighting Service

Product packaging, enclosed literature, or

product specification sheet shall list the

diameter of lamp tubes and the lamp-cap

type, and the length, efficiency and color

rendering index of the lamp.

The packaging or enclosed literature

should specify the rated luminous flux of

the lamps, and should note its equivalency

compared to the luminous flux of an

incandescent lamp for general lighting

service (GLS). The equivalent GLS must

be elected in accordance with IEC 60064.


309

Light output (lm) Power of standard

GLS (W)

≥230 25

≥415 40

≥570 50

≥715 60

≥940 75

≥1,227 90

≥1,350 100

≥2,180 150

≥3,090 200

Materials Lamp and lamp package must comply with

any local regulations regarding disclosure

and disposal, including regulations

regarding toxic materials such as

mercury.

ELI encourages manufacturers to inform

all purchasers about environmentally

responsible options for disposal or

recycling of lamps at end of the useful

lamp life.

Quality Management

System

Manufacturers shall have in place and

implement a Quality Management System

in accordance with ISO 9001-2000 or

equivalent (equivalency to be determined

by ELI).

Product Use Guidance The manufacturer or distributor shall offer

a clear and credible guidance in the

relevant local language on how to select

compatible components to create a highly

efficient lighting system.

Warranty Purchaser may replace a defective ELI-

certified lamp at point of purchase within

12 months from the date of purchase.

A written no-questions-asked warranty in

at least one applicable local language and

a local address for consumer contacts and

complaints must be included with product

when purchased.


310

2. Double-capped Fluorescent Lamps

Double-capped Fluorescent Lamp should meet the performance

specifications below:

Laboratory and Test

Requirements


Laboratory Facility

Must be accredited according to ISO/IEC

17025 and qualified for pertinent lighting

product tests by a recognized national or

regional accreditation body. (See the ELI

Certification Protocol on the ELI website.)

A copy of the accreditation document

must be provided to ELI.

Testing Conditions

Performed at 25±1 °C in an international

standard atmosphere with maximum

relative humidity of 65%; the light

characteristics of high efficient preheated

cathode double-capped T5 fluorescent

lamps shall be performed at 35±1 °C.

Position and Initial

Burn-in

Measurements should be recorded from

products in vertical base-up position, after

an initial burn-in period of 100 hours, at

stabilized light output and current.

Test Data and Sample

Size

The applicants shall submit a separate set

of test reports for each individual model.

The test reports for the lowest wattage

model in each certification unit as

described in 4.1 and 4.3 must be from

testing laboratories, which meet the

conditions described above. For other

rated wattages in the same certification

unit, the test reports from non-accredited

testing laboratories are recognized.

Test data must be from the model for

which qualification is sought. Values

indicated on the Product Application


Lamps should be the testing data from the

samples tested. Measurements of

photometric and electrical characteristics

must be submitted for 8 units of the same

model.


311

Longevity of Test

Results

Longevity of test results is two years,

unless the applicant can document to

ELI’s satisfaction that older test results

accurately portray the performance of the

present model.

Operating

Characteristics


Operating Conditions The product package must declare the

operating temperature conditions.

At 10 °C – 50 °C, with 92%~106% rated

voltage, the lamp can start reliably and

maintain stable operation.

Starting Time The product package must declare the

minimum starting temperature and any

other conditions (such as installation in an

enclosed luminaire) that would affect

either reliable starting or the starting

time.

Starting time Comply with starting characteristics limits

set by IEC 60081.

Lifetime Must have a minimum rated lifetime of

15,000 hours as defined in 3.9. Rated

lifetime should be clearly indicated in

hours on product packaging.

Method of test for the life of a lamp shall

be in accordance with IEC 60081. The

full lifetime testing may be conducted by

manufacturers’ testing facilities or by any

other non-accredited testing facilities.

ELI, nevertheless, may request

clarification and/or additional supporting

documents as appropriate, and reserves the

right to accept or reject the test reports

submitted. Requirements of longevity of

test result in this specification and validity

period of the test report specified in the

ELI Qualification Protocol are not

applicable to the full lifetime test report of

double-capped fluorescent lamp..

Safety Must comply with IEC 61195 and relevant

local regulations.


312

Light Characteristics Performance Specifications

Correlated Color

Temperature

Must comply with IEC 60081 and the

color tolerance shall be within 5SDCM

from the target values.


must appear on the product packaging.

Color Rendering Index Color Rendering Index (CRI) should be at

least 80, as measured in accordance with

CIE13.3.

Lumen Maintenance The luminous flux of the lamp must be >

90% of initial levels at 40% rated of

model’s rated lifetime. Luminous flux

shall be measured according to IEC

60081.

Efficiency Specifications

Lamp wattage shall be classified based on the rated wattage, but the

test wattage shall be within 105% + 0.5 W of rated wattage.

Initial luminous efficacy shall be calculated from initial luminous

flux and input power for the specific lamps measured at rated voltage

and specified temperature. The value of initial luminous efficacy

(lm/W) of the lamps applying for ELI shall not be less than the value

indicated in the table.

Input Power

of Lamp

(W)



6500K 5000K 4000K 3500

K

3000

K

2700K

≥ 14 to < 21 60 65

≥ 22 to < 35 70 75

≥ 36 to < 65 78 83

NOTE: This table and requirements are not applicable to high

efficient preheated cathode double-capped T5 fluorescent Note: This

table and requirements are not applicable to high efficient preheated

cathode double-capped T5 fluorescent lamps.

High efficient preheated cathode double-capped T5 fluorescent lamps

that adopt high frequency shall meet the following luminous

efficiency requirements as specified in Table 3.


313

Input

Power of

Lamp (W)



6500K 5000K 4000K 3500K 3000K 2700K

≥ 14 to < 21 80 85

≥ 22 to < 35 90 95

The produce packaging must clearly state the performance of the

following characteristics:

Rated power input in watts, and

Light output in lumens.

Other Specifications

Requirements Specifications

Label Product packaging, enclosed literature, or product

specification sheet shall list the diameter of lamp

tubes and the lamp-cap type, and the length,

efficiency and color rendering index of the lamp.

The packaging or enclosed literature should specify

the rated luminous flux of the lamp.

Materials Lamp and lamp package must comply with any

local regulations regarding disclosure and

disposal, including regulations regarding toxic

materials such as mercury.

ELI encourages manufacturers to inform all

purchasers about environmentally responsible

options for disposal or recycling of lamps at end of

the useful lamp life.

Quality

Management

System

Manufacturers shall have in place and implement a

Quality Management System in accordance with

ISO 9001-2000 or equivalent (equivalency to be

determined by ELI).

Product Use

Guidance

The manufacturer or distributor shall offer a clear

and credible guidance in the relevant local language

on how to select compatible components to create a

highly efficient lighting system.

Warranty Purchaser may replace a defective ELI-certified

lamp at point of purchase within 12 months from

the date of purchase.

A written no-questions-asked warranty in at least

one applicable local language and a local address

for consumer contacts and complaints must be

included with product when purchased.


314

315

Appendix C. Levels of Illumination Currently

Recommended

While the convenience of this table sometimes lists locations rather

than tasks, the recommended lux values have been arrived at for specific

visual tasks. The tasks selected for this purpose have been more difficult

ones that commonly occur in the various areas.

In order to assure these values at all times, higher initial levels

should be provided as required by the maintenance conditions.

Where task are located near the perimeter room of a special

consideration should be given to the arrangement of the luminaires in

order to provide the recommended level of illumination on the task.

The illumination levels shown in the table are intended to be

minimum on the task irrespective of the plane in which it is located. In

some instances, denoted by a (†), the values shown will be for equivalent

sphere illumination, E8. The commonly used lumen method of

illumination calculation that gives results only for a horizontal work

plane cannot be used to calculate or predetermine Es values. The ratio of

vertical to horizontal illumination will generally vary from 1/3 for

luminaires having narrow distribution to ½ for luminaires of wide

distribution. For a more specific determination one of the point

calculation methods should be used. Where the levels thus achieved are

inadequate, special luminaire arrangements should be used or

supplemental lighting equipment employed.

Supplementary luminaires may be used in combination with general

lighting to achieve these levels. The general lighting should be not less

than 200 lux and should contribute at least one-tenth the total

illumination level.

Many of the following values have appeared, or in the future will

appear, in other reports of the Society, some of which is jointly

sponsored with other agencies and organizations.

APPENDIX C. LEVELS OF ILLUMINATION CURRENTLY RECOMMENDED

316

Interior Lighting

Area lux

Aircraft Manufacturing

Stock parts

Production

Inspection

Parts manufacturing

Drilling, riveting, screw fastening

Spray booths

Sheet aluminum layout and template work, shaping, and

smoothing of small parts for fuselage, wing sections,

cowling, etc.

Welding

General illumination

Precision manual arc welding

Subassembly

Landing gear, fuselage, wing sections, cowling and

other large units.

Final assembly

Placing of motors, propellers, wing

sections, landing gear

Inspection of assemble ship and its equipment

Machine tool repairs

Aircraft hangars

Repair service only

Armories

Drill

Exhibition

Art galleries

General

On paintings (supplementary)

On statuary and other displays

Assembly

Rough easy seeing

Rough difficult seeing

Medium

Fine

Extra fine

Auditoriums

Assembly only

Exhibitions

Social activities

1100

220

750

1100

1100j

50

10800a

1100

1100

1100

1100

1100

220

320

320

320b

1100c

320

540

1100

5400a

10800a

160

320

50


317

Automobile showrooms (see Stores)

Automobile manufacturing

Frame assembly

Chassis assembly line

Final assembly, inspection line

Body manufacturing

Parts

Assembly

Finishing and inspecting

Bakeries

Mixing rooms

Face of shelves (vertical illumination)

Inside the mixing bowl (vertical mixers)

Fermentation room

Make-up room

Bread

Sweet yeast-raised products

Proofing room

Oven room

Fillings and other ingredients

Decorating and icing

Mechanical

Hand

Scales and thermometers

Wrapping room

Banks Lobby

General

Writing areas

Tellers' stations

Posting and keypunch

Barbers shops and beauty parlors

Book binding

Folding, assembling, pasting, etc.

Cutting, punching, stitching

Embossing and inspection

Breweries

Brew house

Boiling and keg washing

Filling (bottles, cans, kegs)

Candy making

Box department

540

1100

2200

750

1100

2200

540

320

540

320

320

540

320

320

540

540

1100

540

320

540

750†

1600†

1600†

1100

750

750

2200

320

320

540

540


318

Chocolate department

Husking, winnowing, fat extraction

crushing and refining, feeding

Bean cleaning, sorting, dipping, packing,

wrapping

Milling

Cream making

Mixing, cooking, molding

Gum drops and jellied forms

Hand decorating

Hard candy

Mixing, cooking, molding

Die cutting and sorting

Kiss making and wrapping

Canning and preserving

Initial grading raw materials samples

Tomatoes

Color grading (cutting rooms)

Preparation

Preliminary sorting

Apricots and peaches

Tomatoes

Olives

Cutting and pitting

Final sorting

Canning

Continuous-belt canning

Sink canning

Hand packing

Olives

Examination of canned samples

Container handling

Inspection

Can unscramblers

Labeling and cartoning

Central station

Air-conditioning, equipment, air preheater and fan

floor, ash sluicing

Auxiliaries, battery rooms, boiler feed pumps, tanks

compressors, gauge area

Boiler platforms

Burner platforms

Cable room, circulatory, or pump bay

540

540

1100

540

540

1100

540

1100

1100

540

1100

2200a

540

1100

1600

1100

1100

1100

1100

540

1100

2200f

2200a

750

320

110

220

110

220

110

540


319

Chemical laboratory

Coal conveyor, crusher, feeder, scale areas,

pulverizer, fan area, transfer tower

Condensers, deaerator floor, evaporator floor, heater

floors

Control rooms (see Control rooms)

Hydrogen and carbon dioxide manifold area.

Precipitators

Screen house

Soot or sag blower platform

Steam headers and throttles

Switchgear, power

Telephone equipment room

Tunnels or galleries, piping

Turbine bay sub-basement

Turbine room

Visitor's gallery

Water treating area

Chemical works

Hand furnaces, boiling tanks, stationary driers,

stationary and gravity crystallizers

Mechanical furnaces, generators and stills,

mechanical driers, evaporators, filtration,

mechanical crystallizers, bleaching

Tanks for cooking, extractors, percolators, nitrators,

electrolytic cells

Churches and synagogues

Altar, ark, reredos

Choir4 and chancel

Classrooms

Pulpit, rostrum (supplementary illumination)

Main worship area4

Light and medium interior

For churches with special zeal

Art glass windows (test recommended)

Light color

Medium color

Dark color

Especially dense windows

Clay products and cements

Grinding, filter presses, kiln rooms

Molding, pressing, cleaning, trimming

Enameling

110

110

220

110

220

110

110

220

220

110

220

320

220

220

320

320

320

1100e

320e

320†

540e

160e

320d

540

1100

5400

10800

320

320

1100


320

Color and glazing—rough work

Color and glazing—fine work

Cleaning and pressing industry

Checking and sorting

Dry and wet cleaning and steaming

Inspection and spotting

Pressing

Repair and alternation

Cloth products

Cloth inspection

Cutting

Sewing

Pressing

Clothing manufacture (men's)

Receiving, opening, storing, shipping

Examining (perching)

Sponging, decating, winding, measuring

Piling up and marking

Cutting

Pattern making, preparation of trimming, piping,

Canvas and shoulder pads

Fitting, bundling, shading, stitching

Shops

Inspection

Pressing

Sewing

Club and lodge rooms

Lounge and reading rooms

Auditoriums (see Auditoriums)

Coal tipples and cleaning plants

Breaking, screening

Picking

Control rooms and dispatch rooms

Control rooms

Vertical face of switchboards

Simplex or section of duplex facing operators:

Type A—large centralized control room 1676 mm

(66 inches) above floor

Type B—Ordinary control room 1676 mm (66

inches) above floor

Section of duplex facing away from operator

Bench boards (horizontal level)

Area inside duplex switch board

1100

3200a

540

540

5400a

1600

2200a

21500a

3200a

5400a

3200a

320

21500a

320

1100

3200a

540

320

1100

5400a

3200a

5400a

320

110

3200a

540

320

320

540

110


321

Rear of all switchboards

Emergency lighting, all areas

Dispatch boards

Horizontal plane (desk level)

Vertical ace of board [1219 mm (48 inches) above floor,

facing operator]:

System load dispatch room

Secondary dispatch room

Cotton gin industry

Overhead equipment—separators, driers, grid cleaners,

stick machines, conveyers, feeders and catwalks

Gin stand

Control console

Lint cleaner

Bale press

Court rooms

Seating area

Court activity area

Dairy farms (see farms)

Dairy products

Fluid milk industry

Boiler room

Bottle storage

Bottle sorting

Bottle washers

Can washers

Cooling equipment

Filling: inspection

Gauges (on face)

Laboratories

Meter panels (on face)

Pasteurizers

Separators

Storage refrigerator

Tanks, vats

Light interiors

Dark interiors

Thermometer (on face)

Weighting room

Scales

Dance halls

Depots, terminals, and stations

Waiting room

110

30

540

540

320

320

540

540

540

320

320

750

320

320

540f f

300

300

1100

540

1100

5400

320

320

320

220

1100

540

320

750

50

320


322

Ticket offices

General

Ticket rack and counters

Rest rooms and smoking room

Baggage checking

Concourse

Platforms

Toilets and washrooms

Dispatch boards (see control rooms)

Drafting room (see offices)

Electrical equipment manufacturing

Impregnating

Insulating: coil winding

Testing

Electrical Generating Station (see Central Station)

Elevators, freight and passenger

Engraving (wax)

Explosives

Hand furnaces, boiling tanks, stationary driers, stationary

and gravity crystallizers

Mechanical furnace, generators and stills, mechanical

driers, evaporators filtration, mechanical crystallizers

Tanks for cooking, extractors, filtration, percolators,

nitrators

Farm—dairy

Milking operation area (milking parlor and stall

barn)

General

Cow's udder

Milk handling equipment and storage area (milk

house or milk room)

General

Washing area

Bulk tank interior

Loading platform

Feeding area (stall barn feed alley, pens, loose

housing feed area)

Feeding storage area—forage

Haymow

Hay inspection area

Ladders and stairs

Silo

Silo room

1100†

1100†

320

540

110

2200

320

540

1100

1100

220

2200a

320

320

320

220

540

220

1100

1100

220

220

30

220

220

30

220


323

Feed storage area—grain and concentrate

Grain bin

Concentrate storage area

Feed Processing area

Livestock housing area (community, maternity, individual

calf pens, and loose housing holding and resting areas)

Machine storage area (garage and machine shed)

Farm shop area

Active storage area

General shop area (machinery repair, rough sawing

Rough bench and machine work (painting, fine storage,

ordinary sheet, metal work, welding, medium

bench work)

Medium bench work and machine work (fine

woodworking, drill press, metal lathe, grinder)

Miscellaneous

Farm office

Restrooms

Pump house

Farms—poultry (see Poultry industry)

Fire hall (see Municipal buildings)

Flour mills

Rolling, sitting, purifying

Packing

Product control

Cleaning, screens, man lifts, aisleways and walkways, bin

checking

Forge shops

Foodservice facilities

Dinning areas

Cashier

Intimate type

Light environment

Subdued environment

For cleaning

Leisure type

Light environment

Subdued environment

Quick service type

Bright surroundingsn

Normal surroundingsn

Food displays—twice the general level but not under

Kitchen, commercial

30

110

110

75

50

110

320

540

1100

750†

320

220

540

320

1100

320

540

540

110

30

220

320

160

110

540

540


324

Inspection, checking, preparation, and pricing

Entrance foyer

Marquee

Dark surroundings

Bright surroundings

Foundries

Annealing (furnaces)

Cleaning

Core making

Fine

Medium

Grinding and chipping

Inspection

Fine

Medium

Molding

Medium

Large

Pouring

Sorting

Copula

Shakeout

Garage—automobile and truck

Service garages

Repairs

Active traffic areas

Parking garages

Entrance

Traffic lanes

Storage

Gasoline station (see Service station)

Glass works

Mix and furnace rooms, pressing and lehr, glassblowing

machines

Grinding, cutting glass to size, silvering

Fine grinding, beveling, polishing

Inspection, etching and decorating

Glove manufacturing

Pressing

Knitting

Sorting

Cutting

Sewing and inspection

750

320

320

540

320

320

1100

540

1100

5400a

1100

1100

540

540

540

220

320

1100

2200

540

110

50

320

540

1100

2200f

3200a

1100

1100

3200a

5400a


325

Hangars (see aircraft hangars)

Hat manufacturing

Dyeing, stiffening, braiding, cleaning, refining

Forming, sizing, pouncing, flanging, finishing, ironing

Sewing

Homes (see Residences)

Hospitals

Anesthetizing and preparation room

Autopsy and morgue

Autopsy room

Autopsy table

Museum

Morgue, general

Central sterile supply

General, work room

Work table

Glove room

Syringe room

Needle sharpening

Storage area

Issuing sterile supplies

Corridor

General in nursing areas—daytime

General in nursing areas—night (rest period)

Operating, delivery, recovery, and laboratory suites and

service areas

Cystoscopic room

General

Cystoscopic table

Dental suite

Operatory, general

Instrument cabinet

Dental entrance to oral cavity

Prosthetic laboratory bench

Recovery room, general

Recovery room, local for observation

(EEG) encephalographic suite

Office (see Offices)

Work room, general

Work room, desk and table

Examining room

Preparation rooms, general

Preparation rooms, local

1100

2200

5400a

320

1100

10800

540

220

320

540

540

1600

1600

320

540

220

30

320

1100

26900

750

1600

10800

1100

50

750

320

1100

320

320

540


326

Storage, records, charts

Electromyographic suite

Same as EEG but provisions for reducing level in

preparation area to 1

Emergency operating room

General

Local

EKG, BMR, and specimen room

General

Specimen table

EKG machine

Examination and treatment room

General

Examining table

Exit, at floor

Eye, ear, nose, and throat suite

Darkroom (variable)

Eye examination and treatment

Ear, nose, throat room

Flower room

Formula room

Bottle washing

Preparation and filling

Fracture room

General

Fracture table

Splint closet

Plaster sink

Intensive care nursing areas

General

Local

Laboratories

General

Close work areas

Linens (see Laundries)

Sorting soiled linen

Central (clean) linen room

Sewing room, general

Sewing room, work area

Linen closet

Lobby (or entrance foyer)

During day

During night

320

1100

2150

3200

540

540

540

1100

50

0-110

540

540

110

320

540

540

2200

540

540

320

1100

540

1100

320

320

320

1100

110

540

220


327

Locker rooms

Medical records room

Nurses station

General—day

General—night

Desk for records and charting

Table for doctor's making or viewing reports

Medicine counter

Nurses gown room

General

Mirror for grooming

Nurseries, infant

General

Examining, local and bassinet

Examining and treatment table

Nurses station and work space (see Nurses Station)

Obstetrical suite

Labor room, general

Labor room, local

Scrub-up area

Delivery room, general

Substerilizing room

Delivery table

Clean-up room


Recovery room, local

Patients rooms (private and wards)

General

Reading

Observation(by nurse)

Night light, maximum at floor (variable)

Examining light

Toilets

Pediatric nursing unit

General, crib room

General, bedroom

Reading

Playroom

Treatment room, general

Treatment room, local

Pharmacy

Compounding and dispensing

Manufacturing

220

1100†

750†

320

750†

750†

1100†

320

540

320

110

110

220

110

320

110

320

26900

320

320

1100

220

320

20

5

110

320

220

110

320

320

540

1100

1100

540


328

Parenteral solution room

Active storage

Alcohol vault

Radioisotope facilities

Radiochemical laboratory, general

Uptake or scanning room

Examining table

Retiring room

General

Local for reading

Solarium

General

Local for reading

Stairways

Surgical suite

Instrument and sterile supply room

Clean-up room, instrument

Scrub-up area (variable)

Operating room, general (variable)

Operating table


Recovery room, local

Anesthesia storage

Substerilizing room

Therapy, physical

General

Exercise room

Treatment cubicles, local

Whirlpool

Lip reading

Office (see Office)

Therapy, occupational

Work area, general

Work tables or benches, ordinary

Work table or benches, fine work

Toilets

Utility room

General

Work counter

Waiting rooms, or areas

General

Local for reading

X-ray suite

540

320

110

320

220

540

110

320

220

320

220

320

1100

2200

2200

26900

320

1100

220

320

220

320

320

220

1600

320

540

1100

320

220

540

220

320


329

Radiographic, general

Fluoroscopic, general (variable)

Deep and superficial therapy

Control room

Film viewing room

Darkroom

Light room

Filing room, developed film

Storage, undeveloped films

Dressing rooms

Hotels

Bathrooms

Mirror

General

Bedrooms

Reading (books, magazine, newspapers)

Inkwriting

Make-up

General

Corridors, elevator, and stairs

Entrance foyer

Front office

Linen room

Sewing

General

Lobby

General lighting

Reading and working area

Marquee

Dark surroundings

Bright surroundings

Ice making—engine and compressor room

Inspection

Ordinary

Difficult

Highly difficult

Very difficult

Most difficult

Iron and steel manufacturing

Open hearth

Stock yard

Charging floor

Pouring slide

110

0-540

110

110

320

110

320

320

110

110

320

110

320

320

320

110

220

320

540

110

220

110

320

320

540

220

540

1100

2200

5400a

10800a

110

220


330

Slag pits

Control platform

Mold yard

Hot top

Hot top storage

Checker cellar

Buggy and door repair

Stripping yard

Scrap stockyard

Mixer building

Calcining building

Skull cracker

Rolling mills

Blooming, slabbing, hot strip, hot sheet.

Cold strip, plate

Pipe, rod, tube, wire drawing

Merchant and sheared plate

Tin plate mills

Tinning and galvanizing

Cold strip rolling

Motor room, machine room

Inspection

Black plate, bloom and billet chipping

Tin plate and other bright surfaces.

Jewelry and watch manufacturing

Kitchens (see Foodservice facilities or residences)

Laundries

Washing

Flat work ironing, weighing, listing, marking

Machine and press finishing, sorting

Fine hand ironing

Leather manufacturing

Cleaning, tanning and stretching, vats

Cutting, fleshing and stuffing

Finishing and scarfing

Leather working

Pressing, winding, glazing

Grading, matching, cutting, scarfing and sewing

Library

Reading area

Reading printed material

Study and note taking

Conference areas

220

320

50

320

110

110

320

220

110

320

110

110

320

320

540

320

540

540

540

1100

2200j

5400a

320

540

750

1100

320

540

1100

2200

3200a

320†

750†

320†


331

Seminar rooms

Book stacks (30 inches above floor)

Active stacks

Inactive stacks

Book repair and binding

Cataloging

Card files

Carrels, individual study areas

Circulation desks

Rare book rooms —archives

Storage areas

Reading areas

Map, picture, and print rooms

Storage areas

Use area

Audiovisual area

Preparation rooms

Viewing rooms (variable)

Television receiving room (shield viewing screen)

Audio listening areas

General

For note taking

Record inspection table

Microform areas

Files

Viewing areas

Locker room

Machine shops

Rough bench and machine work

Medium bench and machine work, ordinary automatic

machines, rough grinding, medium buffing and polishing

Fine bench and machine work, fine automatic machines,

medium grinding, fine buffing and polishing

Extra-fine bench and machine work, grinding, fine work

Materials handling

Wrapping, packing, labeling

Picking stock, classifying

Loading, trucking

Inside truck bodies and freight car

Meat packaging

Slaughtering

Cleaning, cutting, cooking, grinding, canning, packing

Municipal buildings—fire and police

750†

320r

50r

750

750†

1100†

750†

750†

320

1100†

320

1100†

750

750

750

320

750†

1100a

750†

320

220

540

1100

540a

10800a

540

320

220

110

320

1100


332

Police

Identification

Jail cells and interrogation rooms

Fire hall

Dormitory

Recreation room

Wagon room

Museums (see Art Gallery)

Nursing homes

Corridors and interior ramps

Stairways other than exits

Exit stairways and landings, on floor

Doorways

Administrative and lobby areas, day

Administrative and lobby areas, night

Chapel or quite area, general

Chapel or quite area, local for reading

Physical therapy

Occupational therapy

Work table, course work

Work table fine work

Recreation area

Dining area

Patient care units (or room), general

Patient care room, reading

Nurse's station, general

Day

Night

Nurse's desk, for charts and records

Nurse's medicine cabinet

Utility room, general

Utility room, work counter

Pharmacy area, general

Pharmacy, compounding, and dispensing area

Janitor's closet

Toilet and bathing facilities

Barber and beautician areas

Offices

Drafting room

Detailed drafting and designing, cartography

Rough layout drafting

Accounting offices

Auditing, tabulating, bookkeeping, business machine

1600†

320

220

320

320

220

320

50

110

540

220

50

320

220

320

1100

2200

540

320

220

320

540†

220

750†

1100†

220

540

320

1100

150

300

500

2200†

1600†


333

operation, computer operation

General offices

Reading poor reproduction, business machine operation,

computer operation

Reading handwriting in hard pencil pr poor paper,

reading fair reproductions, active filing, mail sorting

Reading handwriting in ink or medium pencil or good

quality paper, intermittent filing

Private offices

Reading poor reproductions, business machine operation

Reading handwriting in hard pencil on poor paper,

reading fair reproductions

Reading handwriting in ink or medium pencil on good

quality paper

Reading high contrast or well-printed materials

Conferring and interviewing

Conference room

Critical seeing task

Conferring

Note-taking during projection (variable)

Corridors

Packing and boxing (see Materials handling)

Paint manufacturing

General

Comparing mix with standard

Paint shops

Dipping, simple spraying, firing

Rubbing, ordinary hand painting and finishing art, stencil

and special spaying

Fine hand painting and finishing

Extra-fine hand painting and finishing

Paper-box manufacturing

General manufacturing area

Paper manufacturing

Beaters, grinding, calendaring

Finishing, cutting, trimming, papermaking machines

Hand counting, wet end of paper machine

Paper machine reel, paper inspection, and laboratories

Rewinder

Plating

Polishing and burnishing

Power plants (see Central station)

1600†

1600†

1100†

750†

1600†

1100†

7500†

330†

330

1100†

330

330

220k

320

2200a

540

540

1100

320a

540

320

540

750

1100

1600

320

1100


334

Post offices

Lobby, on tables

Sorting, mailing etc.

Poultry industry (see also Farm—dairy)

Brooding, production, and laying houses

Feeding, inspection, cleaning

Charts and records

Thermometers, thermostats, time clocks

Hatcheries

General area and loading platform

Inside incubators

Dubbing station

Sexing

Egg handling, packing and shipping

General cleanliness

Egg quality inspection

Loading platform, egg storage area, etc.

Egg processing

General lighting

Fowl processing plant

General (excluding killing and unloading area)

Government inspection station and grading stations

Unloading and killing area

Feed storage

Grain, feed rations

Processing

Charts and records

Machine storage area (garage and machine shed)

Printing industry

Type foundries

Matrix making, dressing type

Font assembly—sorting

Casting

Printing plants

Color inspection and appraisal

Machine composition

Composing room

Presses

Imposing stones

Proofreading

Electrotyping

Molding, routing, finishing, leveling molds, trimming

Blocking, tinning

320

1100

220

320

540

220

320

160

1080

540

540

220

750

750

1100

220

110

110

320

50

1100

540

1100

2200a

1100

1100

750

1600

1600

110

540

540


335

Electroplating

Photoengraving

Etching, staging, blocking

Routing, finishing, proofing

Tint laying, masking

Professional offices (see Hospitals)

Receiving and shipping (see Materials handling)

Residences

Specific visual tasks1

Dinning

Grooming, shaving, make-up

Handcraft

Ordinary seeing tasks

Difficult seeing tasks

Very difficult seeing tasks

Critical seeing tasks

Ironing (hand and machine)

Kitchen duties

Food preparation and cleaning

Serving and other non-critical tasks

Laundry

Preparation, sorting, inspection

Tub area- soaking, tinting

Washer and dryer areas

Reading and writing

Handwriting reproductions and poor copies

Books, magazines, newspapers

Reading piano or organ scores

Advanced (substandard size)

Advance

Simple

Sewing (hand ad machine)

Dark fabrics

Medium fabrics

Light fabrics

Occasional-high contrast

Study

Table games

General lighting

Conversation, relaxation, entertainment

Passage areas, for safety

Areas involving visual tasks, other than kitchen

Kitchen

540

1100

1100

160

540

750

1100

1600

2200

500

1600

540

540

540

320

750†

320†

1600

750

320

220

1100

540

320

750†

320

110m

110m

320

540


336

Restaurants (see Foodservice facilities)

Rubber goods—mechanical

Stock preparation

Plasticating, milling, Banbury

Calendaring

Fabric preparation, stock cutting, hose looms

Extruded products

Molded products and curing

Inspection

Rubber tire manufacturing

Banbury

Tread stock

General

Booking and inspecting, extruder, check weighing, width

measuring

Calendaring

General

Letoff and windup

Stock cutting

General

Cutters and splicers

Bead Building

Tire Building

General

At machine

In-process stock

Curing

General

At molds

Inspection

General

At tires

Storage

Sawmills

Grading redwood lumber

Schools

Tasks

Reading printed material

Reading pencil writing

Spirit duplicated material

Good

Poor

Drafting, benchwork

320

540

540

540

540

220a

320

540

1100q

320

540

320

1100q

540

540

1600a

320

320

750a

1100

3200q

220

3200a

320†

750†

320†

1100†

1100a

1600a


337

Lip reading, chalkboards, sewing

Classrooms

Art rooms

Drafting room

Home economics rooms

Sewing

Cooking

Ironing

Sink activities

Note-taking areas

Laboratories

Lecture rooms

Audience area

Demonstration area

Music rooms

Simple scores

Advance scores

Shops

Sight-saving room

Study halls

Typing

Corridors and stairways

Dormitories

General

Reading books, magazines, newspapers

Study desk

Service space (see also Storage rooms)

Stairways, corridors

Elevators, freight and passenger

Toilets and wash rooms

Service stations

Service bays

Sales room

Shelving and displays

Rest rooms

Storage

Sheet metal works

Miscellaneous, ordinary bench work.

Presses, shears, stamps, spinning, medium bench work

Punches

Tin plate inspection, galvanized

Scribing

Shoe manufacturing—leather

750

1100a†

1600a

540

540

750

750†

1100

750

1600a

320†

750g†

1100a

1600a

750†

750†

220

110

320†

750†

220

220

320

320

540

1100

160

50

540

540

540

2200j

2200j


338

Cutting and stitching

Cutting table

Marking, buttonholing, skiving, sorting, vamping,

counting

Stitching, dark materials

Making and finishing, nailers, sole layers, welt beaters and

scarfers, trimmers, welters, lasters, edge setters, sluggers,

randers, wheelers, treers, cleaning, spraying, buffing,

polishing, embossing

Shoe manufacturing—rubber

Washing, coating, mill run compounding

Varnishing, vulcanizing, calendaring, upper and sole

Cutting

Sole rolling, lining making and finishing processes

Shop-windowso

Daytime lighting

General

Feature

Nighttime lighting

Main business districts—highly competitive

General

Feature

Secondary business districts or small towns

General

Feature

Open-front stores (see display lighting under Stores)

Soap manufacturing

Kettle houses, cutting, soap chip and powder

Stamping, wrapping and packing, filling and packing soap

powder

Airway (see Service space)

Steel (see Iron and steel)

Stone crushing and screening

Belt conveyor tubes, main line shafting spaces, chute

rooms, inside of bins

Primary breaker room, auxiliary breakers under bins

Screens

Storage battery manufacturing

Molding of grids

Storage rooms or warehouses

Inactive

Active

Rough bulky

3200a

3200a

3200a

2200

320

540

1100

2200

10800

220

1080

1100

5400

320

540

110

110

220

540

50

110

220


339

Medium

Fine

Storeso

Circulation areas

Merchandizing areas

Service

Self-service

Showcases and wall cases

Service

Self-service

Feature displays

Service

Self service

Alteration room

General

Pressing

Sewing

Fitting room

Dressing areas

Fitting areas

Stockrooms

Structural steel fabrication

Sugar refining

Grading

Color inspection

Testing

General

Extra-fine instruments, scales, etc.

Textile mills—cotton

Opening, mixing, picking

Carding and drawing

Slubbing, roving, spinning, spooling

Beaming and splashing on comb

Gray goods

Denims

Inspection

Gray goods (hand turning)

Denims (rapidly moving)

Automatic trying-in

Weaving

Drawing-in by hand

Textile mills—silk and synthetics

Manufacturing

540

320

1100

2200

2200

5400

5400

10800

540

1600

2200

5400

2200

320

540

540

220a

540

2200a

320

540

540

540

1600

1600

540a

1600

1100

2200


340

Soaking, fugitive tinting, and conditioning or setting of

twist

Winding, twisting, rewinding and coning, quilling, slashing

Light thread

Dark thread

Warping (silk or cotton system)

On creel, on running ends, on reel, on beam, on warp at

beaming

Drawing-in on heddles and reed

Weaving

Textiles mills—woolen and worsted

Opening, blending, picking

Grading

Carding, combing, recombing and gilling

Drawing

White

Colored

Spinning (frame)

White

Colored

Spinning (mule)

White

Colored

Twisting

White

Winding

White

Colored

Warping

White

White (at reed)

Colored

Colored (at reed)

Weaving

White

Colored

Gray-goods room

Burling

Sewing

Folding

Wet finishing, fulling, scouring, crabbing, drying

Dyeing

Dry finishing, napping, conditioning, pressing

320

540

2200

1100

2200

1100

320

1100a

540

540

1100

540

110

540

110

540

320

540

1100

1100

1100

320a

1100

2200

1600

3200a

750

540

110a

750

1100


341

Dry finishing, shearing

Inspecting (perching)

Folding

Theatres and motion picture house

Auditoriums

During intermission

During picture

Foyer

Lobby

Tobacco products

Drying, stripping, general

Grading and sorting

Toilets and wash rooms

Upholstering—automobile, coach, furniture

Warehouse (see Storage rooms)

Welding

General illumination

Precision manual arc welding

Woodworking

Rough sawing and bench work

Sizing, planing, rough sanding, medium quality machine

and bench work, gluing, veneering, cooperage

Fine bench and machine work, fine sanding and finishing

21500

750

50

1

50

220

320

2200a

320

1100

540

10800a

320

540

1100

Exterior Lighting

Building (construction)

General construction

Excavation work

Building exteriors

Entrances

Active (pedestrian and/or conveyance)

Inactive (normally locked, infrequently used)

Vital locations or structures

Building surrounds

Buildings and monuments, floodlighted

Bright surrounding

Light surfaces

Medium light surfaces

Medium dark surfaces

Dark surfaces

Dark surroundings

Light surfaces

Medium light surfaces

110

20

50

10

50

10

160

220

320

540

50

110


342

Medium dark surfaces

Dark surfaces

Bulletin and poster boards

Bright surroundings

Light surfaces

Dark surfaces

Dark surrounding

Light surfaces

Dark surfaces

Central station

Catwalks

Cinder dumps

Coal storage area

Coal unloading

Dock (loading or unloading zone)

Barge storage area

Car dumper

Tipple

Conveyors

Entrances

Generating or servicing building

Main

Secondary

Gate house

Pedestrian entrance

Conveyor entrance

Fence

Fuel-oil delivery headers

Oil storage tanks

Open yard

Platforms—boiler, turbine deck

Roadway

Between or along buildings

Not bordered by buildings

Substation

General horizontal

Specific vertical (on disconnects)

Coal yards (protective)

Dredging

Farms—dairy and poultry

General inactive areas (protective lighting)

General active areas (paths, steps, rough storage, barn lots)

Service areas (fuel storage, shop, feed lots, building

160

220

540

110

220

540

20

1

1

50

5

5a

50

20

110

20

110

50

2

50

10

2

50

10

5

20

20

2

20

2

10


343

entrances)

Flags, floodlighted (see Bulletin and poster boards)

Gardensp

General lighting

Path, steps, away from house

Backgrounds—fences, walls, trees, shrubbery

Flowers beds, rock gardens

Trees, shrubbery, when emphasized

Focal points, large

Focal points, small

Gasoline station (see Service stations)

Highways (see Service stations)

Loading and unloading platforms

Freight car interiors

Lumber yards

Parking areas

Self-parking area

Attendant-parking area

Piers

Freight

Passenger

Active shipping area surrounds

Prison yards

Quarries

Railroad yards

Retarder classification yards

Receiving yard

Switch points

Body of yards

Hump area (vertical)

Control tower and retarder area (vertical)

Head end

Body

Pull-out end

Dispatch or forwarding yard

Hump and car rider classification yard

Receiving yard

Switch points

Body of yard

Hump area

Flat switching yards

Side of cars (vertical)

Switch points

30

5

10

20

50

50

110

220

220

110

10

10

20

220

220

50

50

50

20

10

220

110

50

10

20

10

20

10

50

50

20


344

Trailer-on flatcars

Horizontal surface of flatcar

Hold-down points (vertical)

Container-on-flatcars

Service station (at grade)

Dark surrounding

Approach

Driveway

Pump island area

Building faces (exclusive of glass)

Service areas

Landscape highlights

Light surrounding

Approach

Driveway

Pump island area

Building faces (exclusive of glass)

Service areas

Landscape highlights

Ship yards

General

Ways

Fabrication areas

Smokestacks with advertising messages

(see Bulletin and poster boards)

Storage yards

Active

Inactive

Water tanks with advertising messages

(see Bulletin and poster boards)

50

50

30

16

16

20

10r

30

20

30

50

320

320r

75

50

50

110

320

220

10

Sports Lighting

Archery (indoor)

Target, tournament

Target, recreational

Shooting line, tournament

Shooting line recreational

Archery (outdoor)

Target, tournament

Target, recreational

Shooting line, tournament

Shooting line recreational

Badminton

540r

320r

220

110

110r

50r

110

50


345

Tournament

Club

Recreational

Baseball

Major league

Infield

Outfield

AA and AAA league

Infield

Outfield

A and B league

Infield

Outfield

C and D league

Infield

Outfield

Semi-pro and municipal league

Infield

Outfield

Recreational

Infield

Outfield

Junior league (Class I and Class II)

Infield

Outfield

On seats during game

On seats before and after game

Basketball

College and professional

College intramural and high school

Recreational (outdoor)

Bathing beaches

On land

45 m (150 feet) from shore

Billiards

Tournament

Recreational

Bowling

Tournament

Approaches

Lanes

Pins

Recreational

320

220

110

1600

1100

750

540

540

320

320

220

220

160

160

110

320

220

20

50

540

320

110

10

30r

540

320

110

220

540r


346

Approaches

Lanes

Pins

Bowling on the green

Tournament

Recreational

Boxing or wrestling (ring)

Championship

Professional

Amateur

Seats during bout

Seats before and after bout

Casting—bait, dry-fly, wet-fly

Pier or dock

Target [at 24 m (80 feet) for bait casting and 15 m (50 feet)

for wet or dry-fly casting)

Combination (outdoor)

Baseball/football

Infield

Outfield and football

Industrial softball/football

Infield


Industrial softball/6-man football

Infield


Croquet or Roque

Tournament

Recreational

Curling

Tournament

Tees

Rink

Recreational

Tees

Rink

Fencing

Exhibitions

Recreational

Football

Distance from nearest sideline to the farthest row of

spectators

110

110

320r

110

50

5400

2200

1100

20

50

110

50r

220

160

220

160

220

160

110

50

540

320

220

110

540

320

1100


347

Class I Over 30 m (100 feet)

Class II 15 m (50 feet) to 30 m (100 feet)

Class III 9 m (30 feet) to 15 m (50 feet)

Class IV under 9 m (30 feet)

Class V no fixed seating facilities

It is generally conceded that the distance between the

spectators and the play is the first consideration in

determining the class and lighting requirements. However,

the potential seating capacity of the strands should also be

considered and the following ratio is suggested: Class I for

over 30,000 spectators; Class II for 10,000 to 30,000; Class

III for 5,000 to 10,000; and Class IV for under 5,000

spectators

Footballs, Canadian—rugby (see Football)

Football, six-man

High school or college

Jr. high and recreational

Golf

Tee

Fairway

Green

Driving range

At 182 m (200 yards)

Over tee area

Miniature

Practice putting green

Gymnasiums (refer to individual sports listed)

Exhibitions, matches

General exercising

Assemblies

Dances

Lockers and shower rooms

Handball

Tournament

Club

Indoor—four-wall or squash

Outdoor—two-court

Recreational

Indoor—four-wall or squash

Outdoor—two-court

Hockey, field

Hockey, ice (indoor)

College or professional

540

320

220

110

220

10

50

10, 30r

50

50r

110

110

110

540

320

110

50

220

540

320

220

220

110

220

1100

540


348

Amateur

Recreational

Hockey, ice (outdoor)

College or professional

Amateur

Recreational

Horse shoes

Tournament

Recreational

Horse shows

Jai-alai

Professional

Amateur

Playgrounds

Racing (outdoor)

Auto

Bicycle

Tournament

Competitive

Recreational

Dog

Dragstrip

Staging area

Acceleration, 402 m (1320 feet)

Deceleration, first 201 m (660 feet)

Deceleration, second 201 m (660 feet)

Shutdown, 250 m (820 feet)

Horse

Motor (midget of motorcycle)

Rifle [45 m (50 yards)—outdoor]

On target

Firing point

Range

Rifle and pistol range (indoor)

On target

Firing point

Range

Rodeo

Arena

Professional

Amateur

Recreational

Pens and chutes

220

540

220

110

110

50

220

1100

750

50

220

320

220

110

320

110

220

160

110

50

220

220

50r

110

50

110r

220

110

540

320

110

50


349

Roque (see Croquet)

Shuffleboard (indoor)

Tournament

Recreational

Shuffleboard (outdoor)

Tournament

Recreational

Skating

Roller rink

Ice rink, indoor

Ice rink outdoor

Lagoon, pond, or flooded area

Skeet

Targets [at 18 m (60 feet)]

Firing points

Skeet and trap (combination)

Targets [at 30m (100 feet) for trap, 18m (60 feet) for skeet).

Firing points

Ski slope

Soccer (see Football)

Softball

Professional and championship

Infield

Outfield

Semi-professional

Infield

Outfield

Industrial league

Infield

Outdoor

Recreational (6-pole)

Infield

Outfield

Slow pitch, tournament—see industrial league

Slow pitch, recreational (6-pole)—see recreational (6-pole)

Squash (see Handball)

Swimming (indoor)

Exhibitions

Recreational

Underwater—100 lamp lumens per square foot of surface

area

Swimming (outdoor)

Exhibitions

320

20

110

50

110

110

50

10

320r

50

320r

50

10

540

320

320

220

220

160

110

75

540

320

220

110


350

Recreational

Underwater—60 lamp lumens per square foot of surface

area

Tennis, lawn (indoor)

Tournament

Club

Recreational

Tennis lawn (outdoor)

Tournament

Club

Recreational

Tennis, table

Tournament

Club

Recreational

Trap

Targets [at 30 m (100 feet)]

Firing points

Volley ball

Tournament

Recreational

540

320

220

320

220

110

540

320

220

30r

50

220

110

Transportation Lighting

Aircraft

Passenger compartment

General

Reading (at seat)

Airports

Hangar apron

Terminal building apron

Parking area

Loading area

Automobiles

License plates

Rail conveyance

Boarding or exiting

Fare box (rapid transit train)

Vestibule (commuter and inter-city trains)

Aisles

Advertising cards (rapid transit and commuter trains)

Back-lighted advertising cards (rapid transit and commuter

trains) —250 fL (857 cd/m2) maximum

Reading

50

220

10

5

20r

5

110

160

110

110

320

320†


351

Rest room (inter-city trains)

Dining area (inter-city train)

Food preparation (inter-city train)

Lounge (inter-city train)

General lighting

Table games

Sleeping car

General lighting

Normal reading

Prolonged seeing

Railways mail cars

Mail bag racks and letter cases

Mail storage

Road conveyances

Step well and adjacent ground area

Fare box

General lighting (for seat selection and movement)

City and inter-city buses and city stop

Inter-city buses at city bus at country stop

School bus while moving

School bus at stops

Advertising cards

Back-lighted advertising cards (see Rail conveyances)

Reading

Emergency exit (school bus)

Ships

Living areas

State rooms and Cabins

General lighting

Reading and writing

Prolonged seeing

Baths (general lighting)

Mirrors (personal grooming)

Barber shop and beauty parlor

On subject

Day rooms

General lighting

Desks

Dinning rooms and mess rooms

Enclosed promenades

General lighting

Entrances and passageways

General

220

540

750

220

320

110

320†

750†

320

160

110

160

110

20

160

320

320

320†

50

110

320w†

750u†

110

540

540

1100

220w

540w†

220

110

110


352

Daytime embarkation

Gymnasium

General lighting

Hospital

Dispensary (general lighting)

Operating room

General lighting

Doctor's office

Operating table

Wards

General lighting

Reading

Toilets

Libraries and lounges

General lighting

Reading

Prolonged seeing

Purser's office

Shopping areas

Smoking areas

Smoking rooms

Stairs and foyers

Recreation area

Ball rooms

Cocktail lounges

Swimming pools

General

Underwater

Outdoors—60 lamp lumens/square or foot surface

area

Indoors—100 lamp lumens/square of surface area

Theaters

Auditorium

General

During picture

Navigating areas

Chart room

General

On chart table

Gyro room

Radar room

Radio room

Radio room, passenger foyer

320

320

320u

540u

320u

22000

110

320

220

220

320u†

720u†

220u

220

220

160

220

160w

160w

160w

110w

10

10

50u †

220

220

110u

110


353

Ships offices

General

On desks and work tables

Wheelhouse

Service Areas

Food preparation

General

Butcher shop

Galley

Pantry

Thaw room

Sculleries

Food storage (non-refrigerated)

Refrigerated spaces (ship’s stores)

Laundries

General

Machine and press finishing, sorting

Lockers

Offices

General

Reading

Passenger Counter

Storerooms

Telephone exchange

Operating areas

Access and casing

Battery room

Boiler rooms

Cargo handling (weather deck)

Control stations (except navigating areas)

General

Control consoles

Gage and control boards

Switchboards

Engine rooms

Generator and switchboard rooms

Fan rooms (ventilation & air conditioning)

Motor rooms

Motor generator rooms (cargo handling)

Pump room

Shaft alley

Shaft alley escape

Steering gear room

220u

540u†

110u

220u

220u

320u

220u

220u

220u

110

50

220u

540

50

220

540u†

540u†

50

220

110

110

220u

50u

220

320

320

320

220u

220u

110

220

110

110

110

30

220


354

Windlass rooms

Workshops

General

On top of work bench

Tailor shop

Cargo holds

Permanent luminaires

Passageways and trunks

110

320u

540u

540u

30u

10

* Minimum on the task of anytime for young adults with normal and better

than 20/20 corrected vision. For general notes see beginning of tabulation.

For other notes see end of tabulation.

† Equivalent sphere illumination. See general notes at beginning of

tabulation.

* Minimum on the task at any time. For general notes see beginning of

tabulation.

a Obtained with a combination of general lighting plus specialized

supplementary lighting. Care should be taken to keep within recommended

luminance ratios. There seeing tasks generally involve the discrimination

of fine detail for long periods of time and under conditions of poor

contrast. The design and installation of the combination system must not

only provide a sufficient amount of light, but also the proper direction of

light, diffusion, color and eye protection. As far as possible it should

eliminate direct and reflected glare as well as objectionable shadows.

b Dark paintings with fine detail should have 2 or 3 times higher

illumination.

c In some cases, much more than 1100 lux is necessary to bring out the

beauty of the statuary.

d Reduced or dimmed during sermon, prelude or meditation.

e Two-thirds this value if interior finishes are dark (less than 10 per cent

reflectance) to avoid high luminance ratios, such as between hymnbook

pages and surround. Careful planning is essential for good design.

f Special lighting such that (1) the luminous area shall be large enough to

cover the surface which is being inspected and (2) the luminance be within


355

the limits necessary to obtain comfortable contrast conditions. This

involves the use of sources of large area and relatively low luminance in

which the sources luminance is the principal factor rather than the lux

produced at a given point.

g For close inspection, 540 lux.

h Pencil handwriting, reading of reproductions and poor copies 750 lux.

i For close inspection, 540 lux. This may be done in the bathroom, but if the

dressing table is provided, local lighting should provide the level

recommended.

j The specular surface of material may necessitate special consideration in

selection and placement of lighting equipment, or orientation of the work.

k Or not less than 1/5 the level in adjacent areas.

l For size of task plane.

m General lighting for these areas need not be uniform in character.

n Including street and nearby establishments.

o (a) Values are illumination on the merchandise on display or being

appraised. The plane in which lighting is important may vary from

horizontal to vertical. (b) Specific appraisal areas involving difficult seeing

may be lighted to substantially higher levels. (c) Color rendering of

fluorescent lamps is important. Incandescent and fluorescent usually are

combined for best appearance of merchandise. (d) Illumination may often

be made non-uniform to tie in with merchandising layout.

p Values based on a 25 per cent reflectance, which is average for vegetation

and typical outdoor surfaces. These figures must be adjusted to specific

reflectances of materials lighted for equivalent brightness’s. Levels give

satisfactory brightness patterned when viewed from dimly lighted terraces

or interiors. When viewed from dark areas, they may be reduced by at least

½; or they may be double when a high key is desired.

q Localized general lighting.

r Vertical.


356

s Level shown are based on visual considerations. Otherwise for public

attraction and increased business considerations, practice is as follows:

Class Approaches Lanes Pins

Tournament 750 lx 1100 lx 2200 lx Vertical

Recreational 540 lx 750 lx 16000 lx

Vertical

u Supplementary lighting should be provided in this space to produce the

higher levels of lighting required for specific seeing tasks involved.

w The lux values vary widely, depending on the effect desired, the decorative

scheme, and the use made of room; the lighting system should provided at

least the recommended minimum illumination levels.

357

Appendix D. Metal Halide and High

Pressure Sodium (HPS)

Lamps Tables

METAL HALIDE LAMPS Bulb Base ANSI

Ballast

Type

Lumens Rated

Ave. Life

Hours

MOL

in.

LCL

in.

Color

Temp.

K

CRI

Initial

Mean

70 WATTS

T6 G12 M85 or

M98(Alt)

6200 4750 6000 315/16 23/16 3000 85

T6 R7s M85 or

M98(Alt)

6200 4750 10000 45/8 21/4 3000 85

BD17 Med M98 6200 4470 7500 57/16 33/8 3000 85

M98 5890 3800 7500 57/16 33/8 3000 85

PAR30L Med M98 4100 3140 6000 43/4 3000 85

M98 4100 3140 6000 43/4 3000 85

150 WATTS

T6 RX7s M81 or

M102(Alt)

13500 10350 7000 53/8 25/8 3000 85

T6 G12 M81 or

M102(Alt)

13500 10350 6000 45/8 21/4 3000 85

APPENDIX D. METAL HALIDE AND HPS TABLES

358

HIGH PRESSURE SODIUM LAMPS Bulb Base ANSI

Ballast

Type

Lumens Rated

Ave. Life

Hours

MOL

in.

LCL

in.

Color

Temp.

K

CRI

Initial

Mean

35 WATTS

B17 Med S76 2250 2025 16000 5 7/16 3 7/16 1900 22

S76 2250 2025 16000 57/16 3 7/16 1900 22

S76 2150 1935 16000 57/16 3 7/16 1900 22

50 WATTS

B17 Med S68 4000 3600 24000+ 5 7/16 3 7/16 1900 22

S68 4000 3600 24000+ 5 7/16 3 7/16 1900 22

S68 3800 3420 24000+ 5 7/16 3 7/16 1900 22

Ed231/2 Mog S68 4000 3600 24000+ 7 3/4 5 1900 22

S68 4000 3600 24000+ 7 3/4 5 1900 22

S68 3800 3420 24000+ 7 3/4 5 1900 22

70 WATTS

B17 Med S62 6400 5450 24000+ 5 7/16 3 7/16 1900 22

S62 6400 5450 24000+ 5 7/16 3 7/16 1900 22

S62 5950 5050 24000+ 5 7/16 3 7/16 1900 22

Ed231/2 Mog S62 6400 5450 24000+ 7 3/4 5 1900 22

S62 6400 5450 24000+ 7 3/4 5 1900 22

S62 5950 5050 24000+ 7 3/4 5 1900 22

S62 6400 5050 40000 7 3/4 5 1900 22

100 WATTS

B17 Med S54 9500

S54 9500

S54 8800

Ed231/2 Mog S54 9500

S54 9500

S54 8800

S54 9500

APPENDIX E. ILLUMINATION CALCULATIONS

Appendix E. Illumination Calculations

EXAMPLES OF ILLUMINATION DESIGN

The calculations presented below using various tables are only meant to give the user of this manual a general overview of the design of lighting system, showing individual steps from the selection of the recommended luminance level up to the design of lighting layout.

Example E1 Efficiency Method of Illumination Calculation: Illumination of a conference room with luminaries each with 2 x 24W compact fluorescent lamps. Room dimensions L =15.00 m (length) W = 8.00 m (width) H = 3.40 m (ceiling-to-floor height) h = 2.55 m (luminaire-to-work plane height) Required quality of light Conference room: Light color, Ra group 2A Illuminance E = 300 lux Selected lamp 2 x 24 W, Light Color Warm Luminous flux per lamp, φ = 1 800 lumen Lighting design data is available in some format for most luminaires.

357


Table E1.1 Luminaries ceiling mounted Reflectances ρ Ceiling 0.8 0.8 0.8 0.5 0.5 0.8 0.8 0.5 0.5 0.3

Wall 0.8 0.5 0.3 0.5 0.3 0.8 0.3 0.5 0.3 0.3 Surface 0.3 0.3 0.3 0.3 0.3 0.1 0.1 0.1 0.1 0.1 Room factor

(index) K

Room utilization factor in %

0.6 73 46 37 44 36 66 36 42 35 35 0.8 82 57 47 54 46 74 45 51 44 44 1.0 91 66 56 62 54 80 53 59 52 51

1.25 98 75 65 70 62 85 61 66 60 59 1.5 103 82 73 76 69 89 67 72 66 65 2.0 109 91 82 84 78 94 75 78 73 72 2.5 114 98 90 90 84 97 81 83 79 77 3.0 117 103 96 95 90 99 86 87 83 82 4.0 120 109 103 100 95 101 91 91 88 86 5.0 122 113 107 103 98 103 93 93 91 89

This table shows the room utilization factor for numerous combinations of room factors and reflectances (always assuming ideal dispersion). The illuminance E required in a room of area L x W is achieved with n luminaires that have an efficiency ηLB and with lamps with a luminous flux φ. Luminaire efficiency and light distribution of 2 x 24 W compact fluorescent lamps Efficiency = η = 0.58

358


Reflectances (ρ) ρ Ceiling = 0.8 ρ Wall = 0.5 ρ Work surface = 0.3 Room utilization factor (uf) From Table F1, uf = 0.91 Calculation: k = = = 2 L x W

H(L + W) 15 x 8

2.55(15 + 8)

N = = = 18.95 E x L x W 300 x 15 x 8

n x

where:

k – Room Factor (Room Index) E – Illuminance, lux L – Length, meter W – Width, meter h – Height of Work Plane, meters

n – Number of Lamps φ − Luminous Flux (Initial Lumens), lumens

η − Luminaire Efficiency uf – Utilization Factor N – Number of Luminaires Result: 18 luminaires (N is rounded up)

φ x η x uf 2 x 1800 lm x 0.58 x 0.91

359


Recommended arrangement: 3 rows of 6 luminaires

Example E3

360


Example E2 Shopping Mall Width = 15 m Length = 100 m Ceiling height = 3.5 m Desired Illumination = 400 lux Type of Luminaire = 200 mm downlight with 26W compact fluorescent lamp (CFL) Average maintained Illuminance: 400 lux

Lamp data: 26W (CFL) Lamp flux: 1 800 lumen (as per manufacturer’s data) Luminaire data:

200 mm diameter downlight with 2 x 26W CFL Selection of Coefficient of Utilization Step 1: Fill in all information in sketch ρc = 70%

hrc = 3.5m

ρw = 50%

ρf = 70%

L (Length) = 100 m W (width) = 15 m h (height) = 3.5 m

361


Step 2: Determine Cavity Ratio If from manufacturer’s data, CU table are given based on Room

Cavity Ratio RCR = 5h (L + W)

L x W =

5(3.5m) (100 + 15)m(100 x 15) m2

= 1.34

If from manufacturer's data, CU table are given based on Room Index

where:

Room Index (k) = L x W

H (L + W)

k = = 3.72 100 x 15 3.5 (100 + 15

)

Step 3: Obtain effective cavity reflectance: Ceiling : ρcc = 70% Wall : ρw = 50% Floor : ρfc = 20%

Step 4: Obtain Coefficient of Utilization from manufacturer's data:

Based on Fig. 9-28 of IESNA Handbook at RCR 1.34 at 70/50/20 reflectance

RCR CU

1 0.66 1.34 X 2 0.60

by interpolation CU at 1.34 RCR = 0.64

362


Step 5: Compute for the Light Loss Factor (LLF)

LLF = BF x LLD x LDD x RSDD

Ballast Factor (BF) = 0.95 LLD (as per Figure 6.3 of IESNA Handbook, 9th Edition)

= Lumen Maintenance (LLD) of CFL (double) is 85%

LDD under luminaire maintenance category I at very clean room using Table 8.1 where maintenance frequency is every 12 months LDD = 0.96

Since luminaire is Direct downlight (as per Figure 8.4 of ELI handbook)

% Room Surface Dirt Depreciation Factor (RSDDF) is 12%

At 12% RCR of 1.34

10% 0.98 12% x 20% 0.96

by Interpolation, x = 0.976 (RSDD)

LLF = 0.95 x 0.85 x 0.96 x 0.976 LLF = 0.76

Step 6: Compute for Total Initial Lamp Lumens (TILL) using

Equation 8.8

TILL = 400 lux (15m x 100m)(0.64) (0.76)

= 1 233 552.63 lumens

Step 7: Calculate the required numbers of luminaries using Equation 8.9. From table lamp manufacturer’s data, the initial lamp lumens of 26W CFL = 1 800 lumens

363


Numbers of luminaires: =

1 233 552.63 lum(2 lam

ens ps/luminaire)(1 800 lumens/luminaire)

= 343 luminaires

Step 8: Select a practical layout for the luminaire.

Spacing Criterion, SC = spacing distance/mounting height As per Figure 9-28 of IESNA Handbook, for 200 mm open reflector using 2 x 26W CFL, SC = 1.5 Spacing distance = 1.5m x 3.5 m = 5.25 m For this distance, 343 luminaires required to achieve 400 lux illumination cannot be placed for the given area.

Step 9: Calculate Luminaire Spacing using Figure 6.46(a),

Chapter 6 Number of luminaires per row = (15m-5.25m)/5.25 = ~ 2 Number of luminaires per column

= 343/2 (luminaries) x 5.25 m (spacing) = 903 m which exceeded 150 m. Spacing Criterion

with this case is not applicable Assuming spacing at end rows = 1 m Number of luminaires/row = 15-2(1)/2 = 6.5 ~ 7 luminaires/row Transverse spacing = 15-2(l)/6= 2.17 m Total length at each row = 6 x 2.17 m = 13 m Space at end rows = 15-13/2 = 1 m Number of luminaires/column = 343/7 = 49 luminaires/column Longitudinal spacing = 100-2(1)/48 = 2.04 m Total length at each column = 48 x 2.04 m = 98 m Space at end rows = 100m-98m/2 = 1 m Total luminaires = 7 x 49 = 343 luminaires

364


Step 10: Draw plan of the room and indicate the locations of luminaires:

W =

15m

N/column = 49 luminaires

N/rows = 7 luminaires

L = 100m

1m

2.17m

1m

2.04m Step 11: Calculate the actual minimum maintained lighting level:

E = 343/343 x 400 lux = 400 lux (within the target value)

Step 12: Calculate the Unit Power Density (UPD) or connected

load; from manufacturers data, the power input of 2 x 26W CFL using conventional ballast = 90watts, or using electronic ballast = 70 watts

UPD =

(90W/luminaire)(343 luminaires) (15m)(100m)

= 20.58W/m2

365


Example E3 Shopping Mall Width = 15 m Length = 100 m Ceiling height = 3.5 m Desired Illumination = 400 lux Type of Luminaire = 200 mm downlight with 70W Metal Halide Lamp Lamp Flux: 6600 lumens (from manufacturer’s data)

from Table (Figure 9-28) of IESNA handbook CU of metal halide downlight #10 at 70/50/20 reflectance & RCR of 1.34

Step 1: Compute for the coefficient of utilization (based on RCR

computed on Example E2 Step 2)

RCR CU 1 0.69

1.34 x 2 0.63

by interpolation: x (CU) = 0.67

Step 2: Compute for the Light Loss Factor (LLF)

LLF = BF x LLD x LDD x RSDD

Ballast Factor (BF) = 0.95 generally for this type of luminaire LLD of metal halide lamp = 0.85 generally for this type of luminaire LDD = 0.96 generally for this type of luminaire RSDD = 0.976

LLF = 0.95 x 0.85 x 0.96 x 0.976 LLF = 0.76

Step 3: TILL = = 1 783 318.93 lumens (0.67) (0.76)

(400lux )(15m x 100m)

366


Step 4: Compute for the number of luminaires

N = = 179 luminaires 1 783 318.93 lum

6 600 lumens

ens/luminaire

Step 5: Select practical layout for the luminaire

Compute for the number of luminaires/row Spacing Criterion, SC = 1.2, does not apply since total of 179 luminaires cannot be placed on the given area. Assuming spacing criterion = 0.9 Spacing distance between luminaries

= Mounting Height x SC Spacing (Longitudinal) = 3.5 m x 0.9 = 3.15 m

Step 6: Calculate luminaire spacing Number of luminaires/column = 100 ÷ 3.15

= 31 luminaires Total length of column = (31-1) x 3.15m = 94.5 m Space at end of column = (100-94.5) ÷ 2 = 2.75 m Total luminaires at each row = 179 ÷ 31 = 5.7 ~ 6 luminaires Transverse spacing = [15m – 2(1.175m)] ÷ 5 = 2.53 m Total length of each row = 5 x 2.53m = 12.65 m Space at ends of row = (15 – 12.65) ÷ 2 = 1.175 m

367


Step 7: Recompute the number of luminaires

Total number of luminaires = 6 x 31 = 186 luminaires Step 8: Draw plan of the room and indicate the locations of

luminaires:

N column = 31

N row = 6

W =

15m

L = 100m

1.175m

2.53m

2.75m 3.15m

Step 9: Calculate the actual maintained lighting level

E = 186 x 400 lux = 415 lux (within target value)

179

Step 10: Calculate the Unit Power Density (UPD) of the connected load, from lamp manufacturer’s data, the power input of 70W metal halide lamp = 81.5 Watts total power

area UPD = = (81.5 W/luminaire)(186 luminaires)

(15m)(100m) = 10.1 W/m2

368


Example E4 Shopping Mall: Same as Examples E2 and E3 Type of Luminaire = 50% 26W CFL Pinlight, 50% 70W Metal Halide with reflector recessed mounted To achieve 400 Lux = 200 Lux of CFL + 200 Lux of Metal Halide Lamp 200 lux for CFL = 343 x 50% = 172 luminaires (see Example E2 Step 7) 200 lux for MH = 186 x 50% = 93 luminaires (see Example E3 Step 7) Arrange Luminaires For Metal Halide Lamps:

Assuming 6 luminaire/row as per computation shown in Example E3 93/6 = 15.5 ~ 16 column Total MH Luminaires = 6 x 16 = 96 luminaires E = 96/93 x 200 lux = 206 lux Spacing:

Longitudinal = 100-2 (1.175)/15 = 6.51 m Transverse = 15-2 (1.175)/5 = 2.53 m

For CFL Lamps:

Number of lamps/column = 172 Number of luminaires/column = 172/6 = 28 2 rows of CFL placed in between of Metal Halide downlights, so

total CFL fixture for 15 columns = 15 x 2 = 30 luminaires/column Spacing of CFL in between MH downlights

Spacing of downlights = 6.51 m To put 2 rows of downlight in between MH

Spacing between column will be = 6.51/3 = 2.17 m

369


Draw floor plan: MH lampsCFL lamps

W=1

5m

2.17

m

2.17

m

1.17

5m

6.51m

Example E5

Indoor Carpark Width = 75 m Length = 100 m Ceiling-to-Floor height = 3.8 m Desired Illumination Level = 200 lux Type of Luminaire = Low Bay 175W Metal Halide Die-cast

aluminum alloy casing, Electrostatic plastic spray finish, Polycarbonate with multi-lined prism reflector’s surface finish

Step 1: Calculate Utilization Factor

Since manufacturer’s catalog expressed CU table on Room Index and not on Room Cavity Ratio (RCR):

1.175m

53m

2.17

m

2.

L=100m


N/row = 6 luminaires

370


As per formula, RCR= 5h(L + W)

(L x W)

RCR = = 0.443 5(3.8) x (100 + 75)(1 x 75)

Ceiling reflectance = 50 Wall reflectance = 50

RCR CU

0 0.80 0.443 x

1 0.69

By interpolation = 1 – 0 0.69 – 0.80

x – 0.80 0.443 – 0

x = -0.11(0.443) + 0.80 CU = 0.75

Step 2: Compute for Light Loss Factor

LLF = BF x LLD x LDD x RSDDF BF = 0.95 generally for this type of luminaire LLD = 0.85 generally for this type of luminaire LDD = 0.84 for Luminaire at dirty room using Table 8.2 where maintenance frequency is annual

Since Luminaire is direct luminaire, % Room Surface Dirt Depreciation Factor (RSDDF) under dirty environment is 22% RSDDF at 0.443 RCR = 0.95

LLF = 0.95 x 0.85 x 0.84 x 0.95 = 0.644

371


Step 3: Compute for the Total Initial Lamp Lumen (TILL) using Equation 8.8 (200 lux)(75m x 100m) TILL = = 3 105 590 lumens

(0.75) (0.644) Step 4: Calculate the required number of luminaires using Equation

8.9. Lamp Lumen of 175W Metal Halide Lamp = 12900 lumens (generally) Number of Luminaires = 3 105 590 lumens

12 900 lumens/luminaire

= 241 luminaires Select practical layout of luminaire Spacing Criterion = spacing distance/mounting

height = 1.7 Spacing distance between luminaire Transverse Spacing = 1.7 x 3.8m = 6.46 m Number of rows = (75/6.46) = 12 Space at end of rows = (75-(11 x 6.46))/2 = 1.97 m Number of luminaire per row = 241/12 = 20 luminaires (19 spans) Spacing (Longitudinal) = 100-2(1.97)/19 = 5.05 m Total Number of Luminaire = 12 rows x 20 luminaires/row = 240 luminaires

Step 5: Calculate the actual minimum maintained illuminance;

E = 240/241 x 200 lux

= 199.2 lux (within the target value)

372


Step 6: Calculate the Unit Power density (UPD)

Power Input of 175W Metal Halide = 188.5W/unit

UPD =

(188.5W/luminaire)(240 luminaires) (75m)(100m)

= 6.03 W/m2

Example E6 Indoor Single Tennis Court – Club Level

Example of Design of Lighting System: Indoor Tennis Court The calculation presented below using various tables are only meant to give the user of this manual a general overview of the design of lighting system, showing individual steps from the selection of the recommended luminance level, the right luminaire to the design of lighting layout. Example: Indoor Tennis Court with 2 adjacent court Size of Court: 36 m x 30 m Size of playing area: 24 m x 11 m Ceiling height: 10 m Luminaire mounting height: 7 m Desired illumination: 300-500 lux GENERAL INFORMATION Project Identification: Indoor Tennis Court Average Maintained Illuminance: 300-500 lux (for recreational tennis) Type of Luminaire: White Louver Ball Proof (Sports Hall) Luminaire with protective wire guard, with tilting mechanism which allow tilting up to 30 degrees without rotational torque ideal for tennis application. Power Consumption: 112 W Dimension of Luminaire: 231 mm x 1200 mm

373


Lamp: 2x54W T5 Linear Fluorescent Lamps Lamp Data:

Lumen Output: 5000 lumens/lamp Lamp Lumen Depreciation (Lumen maintenance from

manufacturers data) = 95% Ballast to be used: Electronic Ballast Ballast Loss Factor (BLF) = 1.0

Making the ball visible is the key objective in designing a tennis court. This is to ensure that the ball is illuminated wherever it is still in play. This might require a lit volume extension to 4 meters above the net, 1 meter outside the sidelines and 2 meters behind the baseline.

Figure E6.1 Light Volume Requirements for a Tennis Court

374


SELECTION OF COEFFICIENT OF UTILIZATION

Step 1: Fill in all information in sketch ρcc = 70% 10m

7m 36m ρw = 50%

ρfc = 20% 30m Step 2: Determine Cavity Ratio

If from manufacturers data CU table are given based on Room Cavity Ratio

5h x (L + W) RCR = (equation 1)

L x W 5(7.0m)(36 + 30)m

= (36 x 30) m2

= 2.14

If from manufacturer’s data, CU table are given based on Room Index where

L x W Room Index (RI) = (equation 2)

h(L + W)

30 x 36

(RI) = = 2.34 7(30+36)

375


Step 3: Obtain effective cavity reflectance:

Ceiling : ρcc = 70% Wall : ρw = 50% Floor : ρfc = 20%

Step 4: Obtain Coefficient of Utilization from manufacturers data

From manufacturer’s data: at Room Index (RI) of 2.34 at 70/50/20 reflectance

Ball Proof Luminaire Table of Coefficient of Utilization

taken from manufacturer’s data for 2x54W T5 lamps

Room Index 1.0 2.0 2.34 3.0

CU at 70/50/20 reflectance 44 58 x 63

by interpolation CU at 2.72 Room Index = 0.60

Step 5: Compute for the Light Loss factor

LLF = Ballast factor x LLD x LDD x RSDD (equation 3)

BALLAST FACTOR of electronic ballast used = 1.0 (based on manufacturer’s data)

LLD (as per manufacturer’s data) = Lumen maintenance (LLD) of 54WT5 Linear Fluorescent lamps = 95%

LDD under Luminaire maintenance category I at medium clean room using Figure 8.2 where maintenance frequency is every 12 months LDD = 0.90

Since Luminaire is Direct Luminaire Type and subject to 12 months cleaning interval, % Room Surface Dirt Depreciation Factor (RSDDF) = 18%

376


At 18% RCR of 2.14

10% 0.98 18% x 20% 0.96

By Interpolation, RSDD = 0.976 substitute computed values to equation 3 LLF = 1.0 x 0.95x 0.90 x 0.976 LLF = 0.83

Step 6 : Compute for the total number of luminaires required to achieve maintained illumination of 500 lux from the formula (Lumen Method) N x n x Φ x CU x MF(LLF) E = (equation 4) Area where:

E = maintained illuminance (Lux) N = number of luminaires n = number of lamp/s per luminaire Φ = luminous flux or initial lumen of lamp (lumen) CU = coefficient of utilization MF(LLF) = light loss factor or maintenance factor

from equation 4

E x A N = n x Φ x CU x LLF

500 lux (36 x 30m) = 2 x 5 000 lumen x 0.60 x 0.83

N = 108 luminaires

377


Step 7: Select a practical lay out for the luminaire

Design considerations for indoor tennis court. Arrangement and position of the luminaire is critical and there are many factors to consider:

1. The right type of luminaire for application.

a. Should be best suited for tennis application, a ball proof luminaire is required with wire guard and deep luminaire to reduce glare to players and spectators.

b. With tilting mechanism to project lamp output inside the playing area .

2. Contrast can increase visibility much more effectively rather than increased illuminance.

a. Should create sufficient contrast between the ball and its background to allow players to see it. It may involve placing a dark and deliberately unlit background behind a light ball.

3. Spacing of luminaire

a. When the ball hits the floor it momentary meets its own shadow, and the players eye uses this to determine the precise time of the bounce, ideally, a symmetrical dark shadow should fall underneath the ball; this is created by light from directly overhead- either from indirect or from closely-spaced direct luminaire.

378


Transversely mounted luminaries

produced symmetrical shadows. Louvers increases the depth of shadow under the ball, aiding visibility. Deep louvers reduce glare to participants and spectators. <Poor luminaire spacing cause uneven illumination at certain height.

Figure E6.2

Figure E6.3

379


To minimize disturbance for players, light sources where possible, should be placed well outside their primary field of view. In tennis, luminaries are best positioned to either side of the court where players seldom look, rather than directly overhead or either end. Step 8. So for this example lets arrange the computed luminaries

based on the recommendation above:

Lets place rows of luminaires 1 meter outside of the tramlines (sideline) and extending 3 meters beyond the baseline. Each court has its dedicated lighting as any scheme that seeks to light 2 adjacent courts from one row of luminaires does not work. (Refer to Figure E6.4) Luminaires are tilted 30 degrees directed inside the court.

Length of playing area to be lighted = 30 m Luminaire length = 1.2 m/luminaire 30 m Number of luminaire/row = = 25 luminaires/row 1.2 m

Step 9: Compute for the final total number of luminaires

Final total number of luminaries = (25 luminaires/row) (2 rows/court)(2 courts) = 100 luminaires which is 5 luminaires less than the computed values based on average maintained illuminance of 500 lux.

Step 10: Calculate the actual maintained lighting level based on the final number of luminaries computed.

100 E = x 500 lux = 463 lux still within the range of 108 300-500 lux

380


Step 11: Calculate the initial Unit Power Density (UPD) From manufacturer’s data, the power consumption of 2 x 54 W T5 luminaire = 112 W

total power UPD = area

100 luminaires x 112 W/luminaire = 36 m x 30 m 11 200 W = 10 080 m2

= 10.37 W/m²

In this example the Unit Power Density (UPD) of 10.37 W/m² is low and therefore lighting system is efficient, compared to using Metal Halide which has a greater UPD value. So the final arrangement of luminaire in the court is shown in the figure below.

381


A side lighting technique with continuous lamp (25 sets/row) white louvered luminaries complete with protective steel rods (wire guard) within the louver . Luminaires are mounted on trunking that has a tilting mechanism up to 30 degrees to direct light inward of the play area from the sideline.

Figure E6.4

In this design arrangements of luminaries (continuous rows in the sidelines) the key objective is to light the volumetric space above the court rather than the plane of the court. Ballproof Luminaire w/ tilting mechanism Photometric Data of 2x54W Luminaire

Figure E6.5 Luminaire Data (Based on manufacturer’s catalog)

382


Step 12. From the final arrangement of luminaire compute for the

actual Illumination at certain points using Point Method Calculation:

At center court (9, 15m), from the formula of Inverse Cosine Law

I Cos Ø EI = D²

where: I = Luminous Intensity, candela D = distance of luminaire from the calculation point Total illuminance at calculation point shall be the summation of illuminance of 50 luminaires Et = E1 + E2 + ………E50 Luminaire 1 is located at (0, 0.6) Distance of luminaire from calculation point = 15-0.6 = 14.4 m Ø = arctan (x²+y²) = arctan sqrt(9+14.4²)/7 = 67.60² H Compute for D (refer to figure) D = (x²+y²+z²) = (9² + 14.4² + 7²) = 18.37 m Elevation angle = 67.60-30 = 37.60 since luminaire is tilted 30o at 37.60 Luminance distribution as per photometric data = 300 cd/1000 lumen

383


Luminous Flux (Initial Lumen Output) for 54W T5 luminaire = 5 000 lumens, as per manufacturer’s data I = 5 000 lumen x 300 cd/1000 lumen I = 1 500 cd 1 500 cd Cos(37.60°) E1 = 18.37² E1 = 3.52 lux Refer to the tabulated illuminance computed per luminaire Et at (9, 15) = summation of all illuminance computed per luminaire Et = 438.86 lux within target range of 300-500 lux

Continuous luminaire x²+y²+z² Ø 7m

d= x² + y² ψ

6.5m 12m

1m

13m 3m

Figure E6.6 Illustration of Angles and Dimensions

384


Example E7 Outdoor Single Tennis Court – Club Level

30.48 m

12 m

24 m

9.14

m

11 m

18.3

m

. 400W Floodlights

Figure E7.1

Calculation Procedures: The following procedures apply to sports lighting design using the point method calculations with direct distribution luminaires. This calculation method relies on inverse square law, the cosine law and photometric distribution of the luminaire. 1. Based on the type of sport, skill level of play, size of the facility;

television broadcasting circumstances, and or architectural or structural requirements, determine the design criteria, such as illuminance.

385


Tennis Court: Size of Court (Play area): 24 m x 11 m Lighted Area (PPA): 18 m x 30 m Required Illumination for Class IV (club-level use) (recreational & social play only, with secondary consideration for spectators):

E = 300-500 lux Illumination requirements for other Class of Play:

Class I. For competition play in large-capacity areas and stadium with up to 200 000 spectators.

E = 1 500 lux Class II. For competition play with fewer than 5 000 spectators.

E = 1 000 lux Class III. For competition play primarily for players, though with due consideration for spectators.

E = 750 lux

2. Make preliminary selection of light sources and luminaires based on

their photometric data, such as lumen output, beam angle, candela and lumen distributions, color rendition, and lamp life.

Assuming outdoor luminaire (Floodlights of 400W, metal halide lamp to be used) Lumen Output (Luminous Flux Φ) of 400W MH as per manufacturers data :

Φ = 39 000 lumens

386


Beam angle: Wide beam Type 6 (NEMA Classification) Photometric data of Luminaires (as per manufacturer’s catalog). Distribution for this luminaire (as per manufacturer’s catalog)

3. Use the lumen method to determine the appropriate number of

luminaires.

E =

N x Φ x CU x LLF Area

N =

xE x Area

Φ CU x LLF

RCR = = 2.67 5(6)(18 + 30)

(18 x 30)

since open area , wall & ceiling reflectance = 0 Generally,

CU = 0.80

Compute for the Light Loss Factor

LLF = BF x LLD x LDD x RSDDF General data:

BF = 0.95 LLD = 80% LDD = Floodlights luminaire classified as maintenance

category V, and since in outdoor applications, very dirty conditions are expected

From Figure 8.2 of ELI:

LDD = 0.70 assuming yearly (12months) cleaning period is

selected

387


RSDD from Table 8.2, Percent expected dirt depreciation for 12 months cleaning interval = 30% since luminaire is a direct Luminaire at computed RCR of 2.67 from the table

RSDF = 0.935 LLF = 0.95 x 0.80 x 0.70 x 0.935 LLF = 0.50 E =

N x Φ x CU x LLF

Area

N = = 11 luminaires 300 lux (30 x 18)

39 000 lumens x 0.80 x 0.50

To make it even let assume 12 luminaires placed individually at Post 4. Assign locations and mounting heights of these luminaires based on

the guidelines given. As per Fig. 20-13 IESNA,

18 to 19.8 m (2 courts)

9.84 to 10.6 m (1 court)

14 to 15.24 m

11.6 to 12.8 m

9.74 to 11 m 10.6 to 12.2 m

8 to 9.84 m

6.1 to 7.6 m

1.8

m

3.6

m

6.1

m

Center line of court or playing area

Figure E7.2 Outdoor Tennis.

388


Recommended mounting heights of luminaires on poles for various setbacks, classes of play, and facilities. Angle A should be a minimum of 25º for sharp cutoff type luminaires and a minimum of 30º for floodlights.

Height of post = 6m (within 6.1m-7.6m limit for Class IV) Post Location = 30ft (within 9.84m-10.6m from the center of the

court)

Other option is to mount 2 luminaires in 7m post to reduce the number of post required, but on this example let us use individual luminaire placed in a 6m post.

5. Confirm the selection of beam spread and rough aiming (luminaire

inclination) by manual calculation at few selected grid points (usually aiming is based on center court).

Then compute for the inclination, luminaire is directed to the center of the court at point along its axis.

x = 9.84m

Figure E7.3 The Illuminance at the center of the court along Post#1 Luminaire located at point (0,0) , aimed at center

court along its axis (30, 0) is given by the equation

389


E =

I (Ø) Cos ØD²

The Luminous Intensity distribution for 400W Floodlights are shown in Figure 7.4. The angle required to determine the luminous intensity are calculated as follows: From geometric principles,

Ø = arctan (X²+ Y²)/z ψ = arctan (y/x)

Solve the Equations

Ø = arctan 30² + 0²

19.68 = 56.73°

Therefore angle of inclination of luminaire = 56° within limit as per Fig.20-13 of IESNA.

D = V x² + y² + z² D = (33)² + 0² + (19.68)² D = 38.42 ft

Plot 12 luminaires in the area, luminaire is distributed equally to court area of 11 m x 24 m.

Spacing = 24m/5 = 4.8 m

390


(12, 9.84)

Figure E7.4 Luminous Intensity Distribution of 400W Floodlights

Since there are 12 luminaires installed, each luminaire contributes to the illumination at a point, take for instance at center court (net), located at (12m, 9.84m) the resultant illumination is determined by totaling the contribution of each luminaire to the plane where the point is located. Please refer to Figure E7.4. E at center court (12, 9.84)

= E (p1+p2+p3+p4+p5+p6+p7+p8+p9+p10+p11+p12)

At center court (12, 9.84) influence by Post 1, 6, 7 & 12

391


Ø = arctan = 68.31°

Elevation Angle Г = 68.31°-56= 12.31° since floodlight is tilted at 56°

ψ = arctan (9.84/12) =37.31° D = (12)² + (9.84)² + (6)² D = 16.23 m

Determine Luminous Intensity Distribution @ (12.31°, 37.31°) based on the table above. By interpolation

LI = 290 cd/Klumen= 290 cd/1000 lumen I = LI x Φ I = 290 cd/1000 lumen x 39 000 lumen = 11 310 cd E = = 1.47 fc x 10.76 lux/fc

= 15.86 lux

E1 = 15.86 x 4 = 63.44 lux resultant of p1, p6, p7 & p12 P2, P5, P8, P11 (same point center court at net), 12, 9.84 x = 12 - 4.8 = 7.2 m y = 9.84 m z = 6 m

D = (7.2)² + (9.84)² + (6)² D = 42.96 ft Ø = arctan ( 7.2)² + (9.84)² / 6 Ø= 62.73°

(12)² + (9.84)² 6

11 310 cd x Cos 68.31°(53.26)²

Г = 62.73 - 56 = 6.73° ψ = arctan (9.84/7.2) = 51.79°

392


Luminous Intensity distribution at (6.73, 51.79°) by interpolation = 302 cd/klumen I = 302 cd/klumen x 39 klumen I = 11 778 cd

E = = 2.92 fc = 31.46 lux

11 778 cd Cos 62.73 (42.96)²

E2 = Ep2, Ep5, Ep8, Ep12 E2 = 31.46 lux x 4 = 125.85 lux

E3 at p3, p4, p9, p10 same point center court at net (12, 9.84)

x = 12m - 9.6m = 2.4 m y = 9.84 m z = 6 m

D = (2.4)² + (9.84)² + (6)² D = 11.2 m Ø = arctan (2.4)² + (9.84)² / 6 = 57.60° Г = 57.60 – 56 = 1.6° ψ = arctan (9.84/2.4) = 75.3°

Luminous Intensity Distribution at 1.6, 75.3° = 308 cd/klumen

E = 308 cd/klumen x 39 000 lumen x Cos 57.60°

(11.2)²

E = 4.78 fc = 51.43 lux E3 = 51.43 x 4 = 205.72 lux

Resultant Illumination at center Court (12m, 9.84m)

E total center court = E1 + E2 + E3

393


Et = 63.44+ 125.85 +205.72 Et = 395

Repeat the process by varying the number of luminaire, location, mounting height, and aiming directions until the target illuminance at each points meet the required illuminance level.

Intermediate Calculation Results at Various Points Lux

394


MH lampsCFL lamps

395

W=1

5m

2.17

m

2.17

m

1.17

5m

6.51m

1.175m

2.53m

2.17

m

L=100m




MH lampsCFL lamps

2.17

m

2.17

m

1.17

5m

W=1

5m

6.51m 1. 2.

175m

53m

2.17

m

L=100m



396

397

Appendix F. Tables

APPENDIX F. TABLES

Tab

le F

1 Pe

rcen

t Eff

ectiv

e C

eilin

g or

Flo

or C

avity

Ref

lect

ance

s for

V

ario

us R

efle

ctan

ce C

ombi

natio

ns*

398

APPENDIX F. TABLES

T

able

F1

Con

tinue

d

399

APPENDIX F. TABLES

Table F2 Coefficient of Utilization for Typical Luminaires

400

APPENDIX F. TABLES

Table F2 (Continued)

401

APPENDIX F. TABLES


402

APPENDIX F. TABLES


403

APPENDIX F. TABLES


404

APPENDIX F. TABLES


405

APPENDIX F. TABLES


406

APPENDIX F. TABLES


407

APPENDIX F. TABLES


408

APPENDIX F. TABLES


409

APPENDIX F. TABLES

Table F3 Multiplying Factor for Effective Floor Cavity Reflectances Other Than 20% (0.2)

410

APPENDIX F. TABLES

Table F4 Illuminance Categories: Commercial, Institutional, Residential, and Public Assembly Interiors

AREA/ACTIVITY ILLUMINANCE

Category Auditoriums

Assembly Social activity

Drafting Tracing paper: high contrast

low contrast

Educational facilities Science laboratories Lecture rooms: audience

demonstration

Offices General and private offices Lobbies, lounges, and reception areas Off-set printing and duplicating areas

Reading Copied tasks: photocopies Handwritten tasks: carbon copies

Residences

General lighting: conversation, relaxation, and entertainment

Reading: books, magazines, and newspapers

Service areas Stairways and corridors Toilets and washrooms

C B

E F

E (see Reading)

F

(see Reading) C D

D E

B

D

C C

Source: Adapted from IES Lighting Handbook, 1995 Reference and Application Volume (New York: Illuminating Engineering Society of North America, 1995). Refer to this Handbook for a complete listing of areas and activities.

411

APPENDIX F. TABLES

Table F5 Initial Lumen of High Pressure Lamps

Type of Lamps Wattage Initial Lumens

High Pressure Sodium Clear

High Pressure Mercury

100 150 250 400

175 250 400

9500 16000 26000 50000

8500

11500 20000

412

Appendix G. Ballast Wiring Diagrams

G.1. Rapid Start

a. One lamp (for metal case)

b. Two lamp in series (for metal case)

c. One lamp (for plastic case)

d. Two lamp in series (for plastic case)

413

APPENDIX G. BALLAST WIRING DIAGRAMS

e. One lamp

f. Two lamp in series

g. Three lamp two in series and one parallel

h. Four lamp two in series and two in parallel

414


i. One lamp

j. Two lamps parallel

k. Three lamps in parallel

l. Four lamps in parallel

415


G.2. Instant Start

a. One lamp

b. Two lamps in parallel

c. Three lamps in parallel

416


d. Four lamps in parallel

e. One lamp

f. Two lamps in parallel

417


g. Three lamps in parallel

418

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