Brochure

Lighting and sensors: Reducing energy costs in commercial buildings

R educing energy use makes perfect business sense; it saves money, enhances corporate reputation

and helps everyone in the fight against climate change.This brochure introduces the main energy-saving lighting technologies and demonstrates how simple actions and interventions can save energy and cut operating costs in your office building.

This brochure will help you to understand how to choose artificial lighting equipment that will deliver the most energy-efficient solutions without compromising on quality – a bad lighting scheme is a complete wastes large amounts of energy and is also not a sustainable solution.

In particular, this brochure will give you insight into lighting control, which has become a key component in energy-efficient lighting and has been shown to reduce energy consumption by up to 50% in existing buildings and at least 35% in new buildings – these savings can be the result of reduced electricity usage; reduced heating, ventilation and air conditioning; as well as lower maintenance costs and improved productivity.

Lighting accounts for 18% of electricity use in the commercial sector and 26% in the industrial sector – it is one of the most important influences in the workplace.

Commercial lighting… countless opportunities for energy efficiency in the office

Three points to think about:• Good quality lighting should be designed to matchor enhance the tasks it was installed for and to

respect the needs of the occupants of your office building

• It is not only the visual effects of lighting that should be kept in mind; recent research has revealed that lighting has a clear impact on health and well-being in the workplace

• Daylight is the only freely available light source and yet all too often it is overlooked; well controlled daylight can provide an office space with the best possible lighting effect, superb colour rendering and great user comfort at no additional cost.

The need to reduce operating costs presents the ideal opportunity to make lighting in your office building more efficient and effective.

Four points to consider:• Understand your building’s lighting requirements• Analyse its lighting inefficiencies• Replace energy-intensive lighting systems• Always keep energy efficiency top-of-mind when evaluating and selecting new lamps.

Note:The following properties should meet the quality criteria for all lighting applications in your building: • Colour rendering – the ability of a light source to accurately render all frequencies of its colour

spectrum• Luminance – the intensity of light emitted from a surface per unit area in a given direction• Luminous flux – the energy per unit time (dQ/dt) radiated from a source over visible wavelengths• Lamp lumen depreciation – the values that reflect the overall performance of a lamp over its

lifespan • Starting-up and running characteristics• Dimming capacities• Size • Lifespan.

New generation lighting systems use less electricity, are kinder to the environment and have a longer lifespan than older lighting technologies.

There are significant differences between the efficiencies, colour and colour rendering of different types of lights.

Three measures to think about:• Lumen (lm) – the power of light emitted by a lamp and perceived by the human eye• Luminous efficacy – a lamp’s ability to convert electrical power into visible light expressed in

lumens per watt (lm/W)• Colour Rendering Index – how well a lamp, on a scale of 0 to 100, renders colour. (For instance,

a lamp with a CRI of 100 makes objects appear as they do in sunlight).

Today there is an energy-efficient solution to solve almost any lighting inefficiency in your office building.

Compact Fluorescent Lamps (CFLs)

A curved or folded gas-filled tube (that fits into the space of an incandescent lamp) with a compact electronic ballast on its base, CFLs’ better phosphor formulations have improved its perceived colour to such a degree that some sources rate the best “soft white” CFLs ‘’similar in colour’’ to standard incandescent lamps.

CFLs contain a tiny amount (about 5mg) of mercury that is almost used up by the time lamps are ready for disposal – they do not pose a health risk if handled and disposed of carefully at appropriate municipal waste sites or sign-posted electronic waste (e-Waste) sites.

Wide range of application

Replacing magnetic ballasts with electronic ballasts has removed most of the flickering and slow starting traditionally associated with fluorescent lighting. Moreover, it has allowed the development of smaller CFLs directly interchangeable with many more sizes of incandescent lamps.

Long lifespan

CFLs typically have a service life of 8,000 hours compared to 1,000 hours for incandescent lamps. The lifespan of a CFL is shortened if it is turned on and off frequently; light output decay is exponential – by the end of their lives, CFLs can be expected to produce 70 to 80% of their original light output. The lifetime of any lamp depends on many factors, including:• Operating voltage• Defects• Exposure to voltage spikes• Mechanical shock• On/off frequency• Lamp orientation• Ambient operating temperature.

Cool

Besides using up to 75% less energy than incandescent lamps and lasting up to eight times longer, CFLs also emit less heat. In commercial buildings where air conditioning is almost always required, CFLs reduce the load on the cooling system and, therefore, contribute to additional energy savings and even lower operating costs.

Dimming

Very few types of CFLs have dimming capabilities.• However, some modern CFLs have a range of 2 to 100%, more comparable to that of

incandescent lights.• Cold-cathode CFLs can be dimmed to low levels, making them popular replacements for

incandescent bulbs on dimmer circuits.

Light Emitting Diodes (LEDs)

LEDs use less electricity to operate and produce more light per watt than most of the other light sources – they:• Are about 85% more energy-efficient than conventional incandescent lamps and about 5%

more efficient than Compact Fluorescent Lamps (CFLs) • Have a quick start-up time• Produce full light capacity as soon as they are switched on• Turn off immediately; there’s no ‘fading’ as the lamp cools down (once it is turned off)• Have a colour temperature (warmth) compared to that of incandescent lamps (colour

temperature plays a role in how people perceive colour and experience thermal comfort in office buildings)

• Can last up to five times longer than CFLs, which last about six times longer than incandescent lamps

• Do not burn out or fail but experience lumen depreciation, where the amount of light produced decreases and light colour appearance can shift over time.

Compared to a standard incandescent lamp, CFLs:• Use only one-fifth to one-third of the electricity• Last eight times longer• Although more expensive, can save over five times its purchase price in electricity

costs over its lifetime.

A dimmer switch used in conjunction with a dimmable CFL must be matched to its power consumption range.

When a CFL is dimmed, its colour temperature (or warmth) stays the same, which is counter to most other light sources where colour gets redder as the light source gets dimmer.

LEDs are adversely affected by high temperature and, typically, include heat dissipation elements such as heat sinks and cooling fins.

LED flood lights can reduce your security lighting costs by up to 50% and last up to 20 times longer than Halogen lamps.

Dramatic improvements in technology broadened the applicability of LED luminaires for highly demanding or hazardous locations in your office environment. Moreover, LED luminaires can deliver longer life, enhanced energy efficiency, reduced maintenance demands and equal or better quality light than conventional lighting technologies.

The lifetime of an LED is based on the prediction that the light output decreases by 30%.

Wide range of application

LEDs:• Come in an array of sizes, starting with tiny lamps measuring 5mm• Are available in a range of shapes and colours for a variety of applications • Are extremely versatile, offering impressive flexibility in colour changing and light distribution.

Some LEDs are directly compatible drop-in replacements for incandescent or fluorescent lamps – LED packaging may show:

• Lumen output• Power consumption in watts• Colour temperature in Kelvin or colour description (e.g. “warm white”)• The equivalent wattage of an incandescent lamp of similar luminous output.

Retrofitting

LEDs can easily replace common compact fluorescent or incandescent lamps – they mostly replace incandescent lamps rated from 5 to 60 watts and are made with standard lamp connections and shapes, such as:• An Edison screw base• An MR16 shape with a bi-pin base• A GU5.3 (bi-pin cap)• A GU10 (bayonet fitting)• A B22 bayonet cap.

LEDs are compatible with the voltage supplied to sockets and include circuitry to rectify AC power and convert voltage to an appropriate value. LEDs are also fully dimmable – some models are compatible with dimmers used for incandescent lamps.

A note on power factor: An overall power factor at a point of supply of less than one can result in the following problems:

• Harmonics from lamps could degrade the sine wave of the Alternating Current electricity supply and affect the performance of other equipment on the same feeder.

• More current in transmission lines can lead to more power loss in the form of heat and, therefore, wasted energy.

When purchasing a CFL or LED, make sure to check that the power factor is specified and displayed on the packaging - cheaper lights will not have it specified. With quality lamps, harmonic filters are built in to mitigate the problems associated with low power factor.

Induction lamps

Induction lamps are a relatively old energy-saving lighting technology suited for areas in your office building where:• High ceilings make it difficult, costly or hazardous to access lamps• The advantages of fluorescent lighting are sought but light sources that can start and operate

efficiently in cold temperatures are needed. Unlike most conventional lamps in commercial building applications – such as Sodium Vapour and Metal Halides – induction lamps have an instant “on” and hot re-strike, which makes it suitable for a wide range of applications, including: • Cafeterias• Warehouses• Parking garages• Outdoor areas.Induction lamps are environmentally friendly because they use less energy and mercury per hour of operation than conventional lighting – mercury is in solid form and can be easily recovered for recycling.

Long lifespan

Depending on the type and model, these lamps have a lifespan of 80,000 to 100,000 hours.

Luminous efficacy

When considering commercial lighting applications and using a 200W fixture as an example, an induction lamp will produce 16,000 Lumens and an LED 11,000 Lumens – about 31% less light – with the same energy input.

All the benefits of induction lamps will translate into energy and maintenance cost savings of around 50% compared to energy inefficient lamps.

Power factor

Induction lamps have a high power factor due to its low loss in 98% efficient high frequency electronic ballasts.

Sodium Vapour lamps

High-pressure and low-pressure Sodium Vapour lamps are a type of High Intensity Discharge (HID) lamp that uses sodium under pressure as the primary light producing element.

These lamps have low colour rendering but are more energy-efficient than Metal Halides in areas or applications around your office building where good colour rendering is not a priority, such as security and parking lot lighting.

Mercury Vapour lamps

A Mercury Vapour lamp is a gas discharge lamp that uses an electric arc through vaporised mercury to produce light. With luminous efficacies of 35 to 65 lumens/watt, these lamps – commonly referred to as HBO lamps – are more energy-efficient than incandescent and most fluorescent lights.

Their other advantages are:• A long lifespan in the range of 24,000 hours• High intensity, clear white light output.

They are mostly used for overhead lighting in large areas in or around your office building such as warehouses – they produce white light with a bluish-green tint that is not flattering on human skin.Requiring a warm-up period of four to seven minutes to reach full light output, these lamps are an old technology becoming obsolete due to the high efficiency and better colour balance of Metal Halide lamps.

Metal Halide lamps

Amongst the most energy-efficient white light sources that offer good colour rendering, Metal Halide lamps can be used in a range of indoor and outdoor application in your office building.

They typically have a three- to five-minute start to full brightness and a four- to 20-minute restrike time.

The lighting technology listed in this brochure is not a complete list of available lamps in the market.

Halogen lamps

A Halogen lamp is a type of incandescent lamp that uses halogen gas to increase both light output and rated life, ideal to create bright work areas in your office building.

These lamps are only slightly more energy-efficient than incandescent lamps but are fully dimmable and have very good colour rendering and a long lifespan.

Lighting control can reduce energy consumption by up to 50% in existing buildings and at least 35% in new buildings

It does not matter how efficient a lamp might be if its use is uncontrolled; there will still be waste and unavoidable costs. Lighting controls are the key to managing the use of light and to ensure that the right light is provided in the right place at the right time.

Artificial lighting can be switched off or dimmed, both when there is sufficient daylight and when there is nobody there to benefit from its use. Properly applied lighting controls facilitate this and ensure there is no unnecessary use of electricity.

Automated functions should be combined with user controls to optimise performance. Light and movement sensors can monitor daylight and occupancy and a time clock can manage overall operating hours.

The principle of combining user controls with automatic management is to have an environment where staff switches lights on but then the controls automatically reduce the light level and switches lights off when there is sufficient daylight - or when staff leave a room.

User controls must be easily understood and conveniently located. Wherever there might be doubt, clear labelling should be used.

Automatic lighting controls generally react to three main stimuli: • Movement sensors – occupancy control• Time clocks – timed schedule• Light sensors – daylight linking.

Motion sensors

Motion sensors monitor occupancy and rely on three technologies: Passive Infrared (PIR), ultrasonic detection and microwave detection.

PIR sensors are the most commonly used type in office spaces because they offer a good compromise between value and sensitivity. They can generally monitor smaller areas than the other two methods, which could be beneficial.

The location of a motion sensor is important; it must be able to ‘see’ the activity that requires the light but not beyond that area. Many sensors do not work effectively because people passing close by trigger the lights to come on when it is not actually needed.

If a room is occupied by a single staff member it is reasonable to pass the responsibility of lighting control to that individual. Once an office space is ‘shared’ it becomes more complicated because the occupants may have different lighting needs. ‘Occupation type’ helps inform application in regard to the best choice of local controls.

Motion sensors can be used in two modes – ‘presence’ and ‘absence’ detection. Presence detection automatically switches on the light as soon as it senses movement and switches off when the space is vacant. Absence detection lighting must be switched on manually and the sensor then switches the lighting off when staff vacate an office.

Time control

Whilst timed operation used to be an effective method to control lighting based on predicted occupancy levels in buildings, this doesn’t fit so well with modern, flexible working patterns. To have any chance of success there need to be a very large number of local overrides that are easily found and used. The need for these can mean that systems that rely only on scheduled switching, actually use more energy than a manually operated installation.

In modern, networked control systems, time scheduling is now used to change overall operating modes. The behaviour of other controls may need to be different at certain times of day. They do, however, remain vital in the case of exterior lighting so lights are only on when it is dark outside.

Defining ‘occupancy types’ and appropriate controls

Type of space Examples Controls

Owned Office, small workshop, consulting room.

Wall switch, movement sensor; preferably in combination (absence mode).

Shared Open plan office, production area.

Wall switches, movement sensors, photocell; local and remote operation; combined.

Temporarily owned Meeting room. Wall switch, scene plate, movement sensors; preferably in absence mode.

Occasionally visited Store room, toilet. Wall switch (with time delay), movement sensor; auto operation.

Unowned Corridor (open or closed), stairs.

Remote manual or automatic operation movement sensors; linked to work area lights.

Managed Foyer. Remote manual and automatic operation; time scheduling.

Light sensors

The technologies used to detect light are, in the main, less important than the way they are used.Light sensors are commonly used in two ways:• To observe external (natural) lighting conditions and be

a reference level for the control system to act upon• Mounted in the ceiling, to observe lighting conditions

immediately below.

The use of an outward looking sensor is usually made in applications where a lot of daylight is coming into the building and the control function is limited to switching only. It works on the principle that the amount of daylight penetrating the building will always be directly proportional to the current ambient light. The system then makes decisions about calculated light levels in various parts of the building.

Downward facing, ceiling mounted, light sensors are usually used in office spaces where the intention is to use dimming control to integrate artificial and natural lighting. As daylight increases the sensor automatically reduces the amount of artificial light.

It is generally better practice to use dimming controls when adjusting lighting in response to daylight. The light level in any space will be the sum of the natural and artificial light. If the light level was 1000 lux, with 500 lux provided by the artificial lighting, then a switch off will halve the lighting level and occupants may think the light level is too low. The reaction will be to restore the artificial lighting even if it is not required.

Lighting controls: Applications

Lighting controls can also be categorised by type and application:

Self-managed luminairesSome luminaires are supplied complete with an integral controller; this may be a movement and/or light sensor. Sometimes called intelligent luminaires, these products are suitable for small rooms and any application where each light may be operated independently

Stand-aloneA ‘stand alone’ lighting controller is usually a self-contained device that comprises a sensor and actuator. In most cases the two parts are integrated into one physical package. These controls are independent from each other and suitable for individual spaces like store rooms and toilets.

Room-basedLike the name suggests, these products have been designed to offer convenient control schemes for one room or area. The most common application is a meeting room and the solution may be a number of components, depending on the size of the room and the control needs.

Scene-setting When lighting controls are provided for the primary purpose of comfort and ambience, then a ‘scene-setting’ system is required. Frequently these products are manually operated and are used in auditoriums.

System A lighting control system is usually a building-wide application, meaning all lighting is effectively linked and managed as a whole. A full and networked lighting control system has additional components to the sensors already described. Depending on the installation and application in your office building, a lighting control system may comprise:

• A central supervisor• Area or zone controllers• Lighting Control Modules (LCMs)• Lighting control or dimmer panels• Sensors• Control switches.

Generally, these components are designed to help the system get included within the lighting installation infrastructure.

Energy efficiency lighting action list

Supply your energy and facilities managers with this energy-efficient lighting action list. But first and foremost, remind your staff at every available opportunity to make it a habit to switch off all lights and appliances when not needed.

Action Date �1 Turn off lights in unoccupied areas

Post reminder stickers to turn off lights when leaving an office/area.

Install time switches or occupancy sensors in areas that are briefly occupied and in remote areas such as warehouses, etc.).

Rewire switches so that one switch does not control all fixtures for multiple work areas.

Ensure wall switch timers function properly.

2Determine if existing lighting levels are higher than the recommended levels

Use a light meter to measure light levels and consult the illumination requirements in the OHS Act.

Reduce lighting levels where appropriate.

Employ uniform or task delamping to reduce power and lighting.

3 Review outside lighting needs

Eliminate outdoor lighting where possible and where safety and security are not compromised.

Manually turn lights off. Replace burnt-out lamps with lower wattage lamps.

Replace exterior incandescent lights with more efficient lights such as CFLs, LEDs, Induction or Metal Halide lamps.

Install photo-electric or motion sensors where light needs are intermittent.

4 Ballasts and control gear

Install more efficient ballasts. Ballasts typically have a long-life; replacing ballasts that are still working can be one of the most cost-effective energy efficiency improvements.

5 Remove lamps that are not needed (delamp)

Remove fluorescent lamps controlled by magnetic ballasts in pairs – they are operated and wired in pairs (two fluorescent lamps from a four-lamp fixture). With electronic ballasts, each lamp is controlled individually. Some facilities have seen energy savings of 30% or more as a result of this action.

Remove unnecessary tubes and replace them with “dummy” tubes that draw little current and provide the effect of uniform lighting.

Disconnect ballasts – ballast will continue to use energy when fixtures are switched on.

6 Install more efficient lighting: Quick tips

Replace incandescent lamps with Compact Fluorescent Lamps (CFLs) or Light Emitting Diodes (LEDs).

Replace T-12 with T-8 or T-5 fluorescents.Replace 400W Metal Halides with 360W Metal Halides or preferably 250W and 200W Metal Halides (where a reduction in light levels is acceptable).Replace High Intensity Discharge (HID) lamps such as Halogen lamps with Metal Halides or high-pressur Sodium lamps.Replace fluorescent lamps in high-ceiling applications with induction lamps – they have ultra-long life spans and are perfect when good colour recognition is required. Replace conventional High Intensity Discharge (HID) lamps in high ceiling applications with T-Bay lamps – they are available in two body sizes accommodating two to eight lamps.

7 Employ more effective lighting settings

Lower fixtures or use a lamp extender to increase illumination in a given area.Install reflectors or lenses to spread out and focus light (specular reflectors can improve efficiency by up to 17% in fluorescent lights).

8 Follow a regular maintenance schedule

Establish a regular inspection and cleaning schedule for lamps and fixtures.Replace yellow or hazy lens shading with new acrylic lenses that do not discolour.Replace old lamps at rated life as these consume the same power as new lamps but produce up to 40% less light.Replace old reflectors as these cannot be effectively cleaned.

9 Use daylight effectively

Locate work stations with high illumination needs adjacent to windows.Install light sensors/dimming equipment that automatically compensate for natural light variance.

10 Upgrade exit signs with the help of an expert

Retrofit by replacing incandescent lamps with CFLs.Retrofit by replacing incandescent lamps with Light Emitting Diodes (LEDs).Replace old exit signs with new LED signs.

Credits:

www.carbontrust.com www.labour.gov.za www.sabs.co.za

Regulations

Owners and managers of office buildings – plus employers who occupy office space in those buildings – should take note of the lighting regulations set out in SANS 10114-1 and the Occupational Health and Safety (OHS) Act of 1993.• SANS 10114 provides basic guidelines and recommendations for the creation of good viewing

conditions and a comfortable visual environment. Although the recommendations are primarily intended for interior workplaces, they also apply, in general, to other interior locations. The visual environment should be such that essential task details are easily visible and that adverse factors, which can cause visual discomfort, are appropriately controlled or excluded.

Although SANS 10114 recognises the need for good energy management and cost-effective lighting schemes, this should not lead to the lowering of the recommended well-established standards needed to promote efficient work, safety and welfare.

Revisions, amendments and affirmations of SANS 10114-1 are conducted periodically to keep pace with international developments in lighting and lighting products and to apply the guidance from international standardisation bodies such as CIE, IEC, ISO and others.

Extract from the Occupational Health and Safety (OHS) Act, 1993:• Every employer shall cause every workplace in his undertaking to be lighted in accordance

with the illuminance values specified in the Schedule to these regulations: Provided that where specialised lighting is necessary for the performance of any particular type of work, irrespective of whether that type of work is listed in the Schedule or not, the employer of those employees who perform such work shall ensure that such specialised lighting is available to and used by such employees.

For detailed information visit:

www.labour.gov.za www.sabs.co.za

Eskom’s Energy Advisors are on standby to assist you:

Eskom’s national Advisory Service offers information on manufacturers and suppliers of energy efficient electro-technologies such as lighting. The team can also advise businesses on:

• Reducing energy usage• Doing walk-through energy assessments to identify energy usage patterns, energy needs, areas

of energy wastage and energy-saving opportunities• Improving the energy efficiency of operations and electrical systems and processes • Prioritising maintenance as an important contributor to reducing energy usage• Finding SANAS approved energy savings Measurement & Verification Authorities.

Advisors can also provide information on funding opportunities for energy efficiency projects.

Call 08600 37566, leave your name and number and an Eskom Energy Advisor will contact you. Alternatively, ask for a specific advisor to contact you.

Visit www.eskom.co.za/idm for more information.

Issued by Eskom Integrated Demand Management October 2015Eskom Holdings SOC Ltd Reg No 2002/015527/30