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The Lighting Handbook Your concise reference book – always ready to hand.
The Lighting Handbook
Your concise reference book always ready to hand.
Chapter 2
Standard values for indoor and outdoor lighting Based on the new European standards
Chapter 9
Checklists
Chapter 3
Lighting application
Chapter 4
Technology
Chapter 7
Emergency lighting
Chapter 5
Lamps
Chapter 8
Technology and tables
Chapter 10
Design tools
Chapter 6
Lighting control and control gear
Chapter 1
Lighting technology
4th edition, revised and updated: October 2013
Imprint:
For questions and suggestions onThe Lighting Handbook:
Zumtobel Lighting GmbHSchweizer Strasse 30Postfach 726851 Dornbirn, AUSTRIAT +43/(0)5572/390-0F +43/(0)5572/22 826
The Lighting Handbook
The Lighting Handbook
Chapter 1
Lighting technology
What is light? 6 What is light? 6 What does the human eye see? 6 Light has a triple effect 7
Basic parameters used in lighting 8 Luminous flux 9 Luminous intensity 9 Illuminance 9 Luminance 9
Quality characteristics of lighting 10 The right light traditional and new quality criteria 10 Illuminance definition of terminology 10 Glare glare limitation 12
On quality characteristics 13 UGR limits 13 Illuminance levels on ceilings and walls 15 Spatial illumination 15 Light colour 16 Colour rendering 16
Measuring illuminance 17
Types of lighting 18
Lighting concepts 20
Humanergy Balance 22 Comprehensive assessment of lighting quality (ELI) 22 Calculation of energy efficiency (LENI) 23 Visual performance 24 Vista 24 Visual comfort 24 Vitality 25 Empowerment 25
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Light is that part of the electromagnetic spectrum that is perceived by our eyes.The wavelength range is between 380 and 780 nm.
By day we see in colour, while at night we can only see in shades of grey.
What is light?
What does the human eye see?What is light?
Wavelength [m]
10-10
10-5
100
105
Gamma rays
X-rays
Ultraviolet
Infrared
Microwaves
Radio waves
Television, VSW
Medium wave
Light
Relative spectralbrightness perception
Wavelength [nm]
Wavelength [nm]
1.0
0.8
0.6
0.4
0.2
Night Day
350 450 550 650 750
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Light has a triple effect
Light for visual functions Illumination of task area in conformity with relevant standards Glare-free and convenient
Light creating biological effects Supporting peoples circadian rhythm Stimulating or relaxing
Light for emotional perception Lighting enhancing architecture Creating scenes and effects
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Luminous flux Luminous intensity Illuminance Luminance
Basic parameters used in lighting
Luminous flux
Luminance L
Lumen [lm]
[lm/sr*m2]=[cd/m2]
Luminous intensity Illuminance E
Candela [lm/sr]=[cd] Lux [lm/m2]=[lx]
= solid angle into which luminous flux is emitted A = area hit by luminous fluxAL cos = visible areas of light source = reflectance of area = 3.14 * = for diffuse surface areas
=
E =
A
L =
AL cosL =
E *
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Luminous fluxThe luminous flux describes the quantity of light emitted by a light source. The luminous efficiency is the ratio of the luminous flux to the electrical power consumed (lm/W). It is a measure of a light sources economic efficiency.
Abbreviation: Phi Unit: lm Lumen
Abbreviation: Unit: cd Candela
Abbreviation: E Unit: lx Lux
Abbreviation: L Unit: cd/m2
IlluminanceIlluminance describes the quantity of lumi-nous flux falling on a surface. It decreases by the square of the distance (inverse square law). Relevant standards specify the required illuminance (e.g. EN 12464 Lighting of indoor workplaces).
Illuminance: E(lx) = luminous flux (lm)
area (m2)
Luminous intensityThe luminous intensity describes the quantity of light that is radiated in a parti-cular direction. This is a useful measurement for directive lighting elements such as reflectors. It is represented by the luminous inten sity distribu tion curve (LDC).
LuminanceLuminance is the only basic lighting para-meter that is perceived by the eye. It specifies the brightness of a surface and is essentially dependent on its reflectance (finish and colour).
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The right light traditional and new quality criteria
Illuminance definition of terminology
Traditional quality criteria Glare limitation Good modelling Correct light colour Avoidance of reflections Harmonious brightness distribution Sufficient illumination level Appropriate colour rendering
Illuminance maintenance value m: value below which the illuminance level must not fall in the visual task area.
Visual task area: illuminance levels are specified for specific visual tasks and are designed for the area in which these may take place.
If the exact location is unknown, the room as a whole or a defined area of the work-station is used for specification.
The visual task area may be a horizontal, vertical or inclined plane.
Area immediately surrounding the visual task area: here illuminance may be one level lower than in the visual task area (e.g. 300lx to 500 lx).
New quality criteria Changing lighting situations Personal control Energy efficiency Daylight integration Light as an interior design element
Maintenance factor: the initial value multi-plied by the maintenance factor gives the illuminance maintenance value.The maintenance factor can be determined individually, and takes the installations re-duction in luminous flux caused by soiling and ageing of lamps, luminaires and room surfaces into account.
The maintenance schedule (the cleaning and maintenance intervals for the lamps and installation) must be documented. See also Section 9 Checklists.
Quality characteristics of lighting
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Maintenance value = maintenance factor x initial value
Relative illuminance (%)
operating time
initial value
maintenance value
150
125
100
75
50
25
0
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Glare glare limitation
Direct glare
Reflected glare
Cause Luminaires without glare control Very bright surfaces
Effect Loss of concentration More frequent mistakes Fatigue
Remedy Luminaires with limited luminance
levels Blinds on windows
Cause Reflective surfaces Incorrect luminaire arrangement Incorrect workstation position
Effect Loss of concentration More frequent mistakes Fatigue
Remedy Matching luminaire to workstation
(layout) Indirect lighting Matt surfaces
Quality characteristics of lighting
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European Standard EN 12464 regulates the lighting of indoor workplaces. In doing so, the unified glare rating method is used to evaluate (psychological) glare.
UGR is based on a glare formula. This for-mula takes account of all the luminaires in the system that contribute to the sensation of glare.
UGR levels for luminaires are determined using the tabular method according to CIE117. Zumtobel also specifies the UGR index complied with by all luminaires con-cerned.
Reference values for specific room sizes are given in the data sheets.
UGR levels are available for each individual product in the corresponding photometric data sheet.Example: www.zumtobel.com/42178787(Photometry tab)
The UGR method takes account of the brightness of walls and ceilings (1) as well as all luminaires in the system that contribute to the sensation of glare (2). The result is a UGR index.
The UGR limits are specified in the EN12464 standard for activities and visual tasks (see tables on pages 2939).
On quality characteristics
( )P2UGR = 8 log 0.25 Lb L2
(1) (2)
UGR limits (UGRL) that must not be exceeded:
16 Technical drawing 19 Reading, writing, training, meetings,
computer-based work 22 Craft and light industries 25 Heavy industry 28 Railway platforms, foyers
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The luminance limiting curve method assesses the mean luminance between 45 and 85, and formerly even the glare effect of a luminaire.
The new European standard sets UGR = 19 as the maximum permissible value for offices, which is equivalent to the luminance limiting curve for 500 lx in Quality class 1.
UGR values are available for each individual product in the corresponding photometric data sheet.Example: www.zumtobel.com/42178787(Photometry tab)
A
a
hs
8643
2
18 103 1042 3 4 45 6 8 2 3
Luminance L in cd/m2
Quality class
A123
10002000
7501500
5001000 750
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Illuminance levels on ceilings and walls
Spatial illumination
Unlit ceilings and walls create an unpleasant room impression. Bright surfaces, however, pleasantly enhance the room climate.
The EN 12464 standard therefore requires an illuminance level of at least 30 lx or 50 lx* on ceilings and at least 50 lx or 75 lx* on walls. In fact, these levels ought to be sig-nificantly exceeded and should be at least 175lx on walls.
* in offices, class rooms, hospitals
In order to enhance peoples and objects reco
