Technology overview. Lighting. Bright ideas for more efficient illumination

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1 Technology overview Bright ideas for more efficient illumination

2 Preface Reducing energy makes perfect business sense; it saves money, enhances corporate reputation and s everyone in the fight against climate change. The Carbon Trust provides simple, effective advice to businesses take action to reduce carbon emissions, and the simplest way to do this is to use energy more efficiently. This technology overview introduces the main energy saving opportunities for lighting and demonstrates how simple actions can save energy, cut costs, improve conditions and increase profit margins. 2

3 Introduction is essential for carrying out daily business activity but it can account for up to 40% of a company s total electricity bill. Even making small adjustments to lighting can significantly improve the working environment and, at the same time, save money. Every business has different requirements of lighting. Even so, there are a number of common ways to reduce the energy consumed. Focusing on low and no-cost measures and actions which will have the quickest payback, this overview explores some of the main types of lighting and demonstrates the best energy saving opportunities available. The information in this publication will also in: Assessing the potential for energy savings in lighting and indicating key areas for improvement Providing background knowledge and some practical tips on using lighting as cost effectively as possible Raising awareness of energy conservation amongst staff and motivating them to reduce waste. Why address lighting as a business issue? Quite simply, improving lighting efficiency saves money. In fact, lighting can account for up to 40% of a company s electricity bill, so making changes can have a big effect. In addition to economic benefits, there are of course, social and environmental advantages to reducing energy consumption, such as preserving fossil fuel supply and minimising global warming. With many clients and customers now demanding that companies demonstrate their green credentials, being energy efficient can significantly enhance a business. Who is this publication for? This overview is aimed at those wishing to improve lighting energy efficiency whilst still maintaining the quality of the lit environment in their workplaces. It is appropriate for business leaders and energy managers. This publication covers lighting in general terms so it is relevant to a wide range of sectors. The advice in this publication provides an overview of the main types of lighting, touching on both daylighting and electric lighting. It does not provide detailed design guidance but describes the issues that need to be addressed and where to get further. 3

4 4 for business Providing the right amount of light when and where it is required. Good lighting supports a business by making the work environment safe and complying with regulations. It provides the appropriate amount of light needed for staff to perform their tasks comfortably, creating an attractive business space for workforce, visitors and customers. Safety regulation Providing adequate lighting is both a legal obligation and a health and safety issue. The Workplace (Health, Safety and Welfare) Regulations 1992 state that lighting must be sufficient to enable people to work and move about safely. and light fittings must not create any hazard and automatic emergency lighting, powered by an independent source, must be provided where sudden loss of light would create a risk. The way an area is lit whether by daylight, electric light or a combination of the two affects the safety and performance of its occupants. Obviously it is in the business s interests for staff to have enough light to work comfortably, but this does not necessarily mean that the brighter an area is, the better. As well as providing adequate minimum levels of illumination, work spaces should not be overly bright. Using lighting levels that are higher than recommended could prove counter productive as the working area could be too bright for comfort, especially where working with light materials (such as white paper). to maximise business can play an important part in creating the right atmosphere in a business. Retail lighting can to focus attention on key displays and engage customers attention Hospitality lighting s to create the desired ambiance for guests Office based companies lighting can be used to make a reception feel welcoming, provide attractive workstations and create a professional feel for staff and visitors Industrial sectors providing appropriate lighting for each task minimises hazards and leads to peak productivity. Appropriate and efficient lighting is crucial for providing the right work environment and maximising savings. Figure 1 and productivity 20 Relative errors 10 Work rate Illuminance (Lux) % Work rate The right amount of light For example, the graph opposite shows how better illumination enables even simple tasks to be carried out faster and with fewer mistakes. The relative errors decrease as lighting levels increase. However, in this case, there would be no significant benefits if illumination levels were raised above 600 lux (the measurement of light intensity).

5 Energy consumption It is possible for lighting to support most business requirements and be energy efficient at the same time. Factors that impact on energy consumption in lighting include: The qualities of the light How people use it to create the right lighting conditions (which lights are on and for how long) The equipment used the lamps, fittings and controls. For the best possible results, all elements in a lighting system need to be considered for the particular application. The basic rules to achieve energy efficient lighting are: Design for adequate but not excessive levels of lighting Use the most efficient lamps and fittings suitable for the task Use light colours on walls and ceilings to best reflect light Use the minimum number of lamps and fittings possible Use appropriate controls Establish an effective maintenance program. for business ways to save Five main areas are considered in this overview: 1. Reduce the need the design and specification of lighting systems have a big impact on energy use and hence, energy spend. Sometimes nature provides the best solution to lighting needs. See page 14 to find out more. 2. Good housekeeping and people issues the way occupants use a lighting system plays a big role in how it performs. See page 15 for tips on how staff can learn to control their systems efficiently. 3. Maintaining existing systems regular maintenance is vital for maximising energy savings and maintaining a comfortable working environment as explained on page Understanding and using controls learning how to set and regulate lighting controls can provide substantial savings and enhance comfort conditions for building occupants. See page 19 for more information. 5. Upgrading and refurbishment there are some excellent opportunities for energy saving whenever upgrades or refurbishment is planned. Page 22 shows how new efficient equipment can often pay back its costs very quickly. Did you know? In the UK, lighting consumes around 58,000GWh each year which amounts to about 20% of all the electricity generated. It is possible to cut your lighting bills by up to 30% by implementing energy saving measures outlined in this overview. 5

6 6 Technology overview All lighting systems, no matter how complex, are made up of three basic components: Lamp the source of the light, for example, the bulb. Examples of lamp types are given in the next few pages Luminaire a light fitting that incorporates the lamp. These are discussed on page 11 Controls manual or automatic switching equipment, which operates the lighting system. See the section on control (page 19) for more information. Lamps The lamp is central to any lighting system and choosing the right one is vital for maximising savings. The light from each type of lamp can be defined in terms of colour, brightness and warmth. Lamps can also be compared by their efficiency and life. There are two main categories of lamp which create light differently: filament lamps and discharge lamps. A third type, light emitting diode (LED), is outlined below, although not discussed extensively in this publication as this is emerging technology which is not utilised widely in business applications at present. Filament lamps Light emitting diodes (LEDs) The filament has high resistance to electricity. Light is produced when the filament gets so hot it glows. This is a fundamentally inefficient method, producing more heat than light. This is the way all traditional tungsten light bulbs work. A variant of this is the tungsten halogen, which also employs a filament, but in a bulb containing halogen gas. Light emitting diodes (LEDs) can be very efficient, relying on a pure semi-conductor to emit light (but not heat or noise) as a response to an electric current. At the moment, common business applications include illuminated signs, such as emergency lighting, for which they are excellent. Recent advances in the technology have led to a new generation of LEDs which offer better colour properties than previous models and, often, can be fitted directly into existing fittings. This could mean that LEDs are appropriate for a wider range of applications. To explore these options, contact a specialist manufacturer. Filament lamps are very common, although their poor efficacy means that they are increasingly being replaced with more efficient alternatives such as compact fluorescent lamps. Discharge lamps Electricity creates a charge which, when applied to a gas filled lamp at the correct voltage, causes the gas to emit energy. Most of this energy is light but some heat and noise is also produced. To obtain and maintain the correct voltage, additional control gear called a ballast (or sometimes starter or choke ) is needed. This is how most non-tungsten lights work including fluorescent, sodium metal halide and mercury.

7 At a glance Qualities of systems and components Qualities of a lit space Illuminance the measurement of light falling on a surface, measured in lux, that is, lumens/m2. Efficacy the amount of light provided relative to the amount of energy used, measured in lumens per Watt once the lamp has reached full brightness. The higher the value the more light is gained for the same energy. Colour temperature a measure of the colour appearance of a light source ranging from warm light (for example, the light a candle produces) through to cool light (for example, a bright white fluorescent light). This is measured in Kelvin (K). Lamps below 3,300K are classed as warm whilst those above 5,300K are cold. Colour rendering the ability of a lamp to show surface colours accurately, measured in Ra. The lower a lamp s Ra value relative to an excellent value of 100, the poorer the lamp s colour rendering ability. Lamp life how long the lamp should last in operating hours. Warm up the time it takes for a lamp to reach 80% of maximum output from cold. Re-strike time taken for a warm discharge lamp to reach 80% of maximum light output when power is interrupted. When considering lamp types, choose the most efficient (highest efficacy) to meet but not exceed general lighting needs (such as brightness or colour) and regulations (such as health and safety). Did you know? To be energy efficient, the Carbon Trust recommends switching off lights, including tubular fluorescent lamps. Contrary to common belief that leaving fluorescent lights on saves energy, this type of lamp only uses a few seconds worth of power when it is turned on. 7

8 Identify your lamps Filament lamps Incandescent tungsten filament The most common types are known as general lighting service (GLS) lamps and decorative lamps. The majority of luminaires in most homes use incandescent tungsten metal filament lamps. All filament lamps will reach maximum light output the instant they are switched on, provide good quality, accurate colour rendering and can be dimmed. However, they are expensive to run and produce high levels of unwanted heat. They also have high maintenance costs associated with their relatively short 1,000-hour lamp life. Main applications: Although these are relatively inefficient bulbs, they are found extensively in homes, and businesses alike. Tungsten halogen (quartz halogen) lamps These are versions of the tungsten filament lamp. Many tungsten halogen lamps operate at 12 volts (low voltage) and require a transformer. This light source is compact and can be focused and directed, making it particularly appropriate for spotlighting. In the right application, they are effective but not necessarily efficient, although they are more efficient and last longer than standard tungsten filament lamps if handled carefully. Mains voltage tungsten halogen lamps can be dimmed but low voltage lamps may require a special dimmer depending upon the type of transformer used. They have a high heat output. Main applications: Increasingly used in hospitality, retail, museums, display areas. Figure 3 Tungsten halogen lamps Top tip Tungsten halogen lamps should not be handled with bare hands otherwise oil from the skin can cause an uneven expansion rate of the glass envelope when the lamp is switched on causing the glass to crack. Myth Incandescent filament lamps and tungsten halogen lamps are more aesthetically pleasing than fluorescent lamps. Figure 2 Incandescent tungsten filament lamps Reality Advances in lighting mean that there are now more efficient alternatives which can look just as good and save on energy costs. 8

9 Discharge lamps Figure 4 Tubular fluorescent lamps Fluorescent lamps Tubular fluorescent lamps have 4-10 times the efficacy (dependent on wattage/size) of incandescent lamps and can last up to 18 times longer. Compact fluorescent lamps (CFLs) often look like standard tungsten filament lamps, but work much the same way as fluorescent strip lighting, in that they require an electronic ballast to start and the inside of the tube is coated with phosphor that gives off the light. Triphosphor versions of both are available, which are more efficient, have a longer life and maintain their light output levels better than standard halophosphate lamps. Special ballasts can be employed so they can be dimmed. Main applications: Used in offices and commercial buildings and most low bay industrial applications (that is, at heights below 5 meters). Compact fittings mean they can replace traditional tungsten lamps directly. T12, T8 or T5 Low pressure sodium lamps (SOX) This is one of the most efficient light sources available but has poor colour rendering properties and requires up to six minutes to reach full output. It emits a strong yellow light, familiar in street lights and has a shorter lamp life than high pressure sodium lamps (SON). Main applications: Used in street lighting, external car parks and security lighting. Consideration should be given to whether this light should be used where colour CCTV is in operation as the colour rendering properties may not be good enough. Figure 5 Low pressure sodium lamp CFL lamps 9

10 High pressure sodium lamps (SON) Metal halide lamps Figure 6 High pressure sodium lamps High pressure sodium discharge lamps combine high efficacy with long life and are able to operate in cold temperatures. They are particularly suitable for floodlighting and illuminating large exteriors. However, like SOX lamps, they have a long warm-up and re-strike time and are not made for frequent switching. Therefore, they should not be used in conjunction with presence detectors such as is often the case with security lighting. Most versions have poor colour rendering unless SON deluxe versions are used. These, however, have reduced efficacy. Main applications: Used for industrial lighting including high bay applications (indoor spaces with high ceilings), flood lighting and street lighting. These are particularly suitable in situations where lamp access is difficult or expensive, for example, where lights are so high that equipment has to be hired to replace them. These lamps have low energy consumption and give an excellent crisp white light which improves colour rendering. The lamp life of 6,000/12,000 hours is shorter than SON lamps but this is still a long operating life time compared with tungsten lamps. Most models have long warm-up and re-strike times of up to ten minutes. Models labelled hot re-strike reduce this time, though these are less efficient. SON/E (Elliptical) SON/T (Tubular) White sodium Main applications: These bulbs are found in most industrial applications where good colour rendering is important and include high bay areas, floodlighting, external lighting, retail and hotels. Figure 7 Metal halide lamps Elliptical 10 CDM/R CDMT

11 11 High pressure mercury lamps Induction lamps (QL) Luminaires These lamps have generally been superseded in new installations by metal halide or high pressure sodium lamps, which provide significantly better efficacies and light quality. With a lifetime of some 60,000 hours, the induction lamp can burn eight hours a day for more than twenty years. Although not as efficient as many of the alternatives mentioned above, induction lamps can be useful in situations where reliability and a lack of access are considerations. As part of considering which lamps to use, check which fittings are required and how they will influence the light quality and efficiency. Some lamps will require particular kinds of luminaire, and many lamps can be greatly enhanced by efficient luminaires. Mercury lamps provide a cool white light and have poor colour rendering (unless comfort/deluxe lamps are used). They have moderate installation costs, and running costs per lumen of light output are higher than SON and metal halide lamps. Main applications: These bulbs are often found in industrial situations where colour rendering is not of prime importance or where minimum maintenance is required. Main applications: Indoor and outdoor applications requiring increased reliability, where re-lamping and maintenance is awkward or expensive. Figure 9 Induction lamp and generator Discharge vessel Power coupler Figure 8 High pressure mercury lamps HF generator A luminaire s efficiency is measured by its light output ratio (LOR). This is the ratio of the luminaire s light output to the light output of the bare lamp, or lamps. Generally, the LOR is expressed as a percentage. For most situations, a luminaire with an LOR of at least 0.5 (or 50%) or greater is regarded as efficient, but to some extent this will depend on the light output distribution required. Just because a luminaire has a good ratio, it does not mean that the right amount of light will be falling into a space. This is because many luminaires also affect the direction of the light. Consider this when planning a lighting scheme. Careful selection of luminaires can reduce glare and direct light where it is needed. Glare is caused by excessively bright sources of light that can be seen by the occupant in their normal activity, whether directly or by reflection. It can cause discomfort and prevent people from carrying out their jobs effectively. MBF (elliptical) MBF/R Remember that in most cases, light fittings reduce the amount of light provided by the lamp and therefore reduce the overall efficiency of the lighting system.

12 12 Table 1 Properties of lighting a checklist The technical properties of lighting are summarised in the table below. Consult this list when thinking about efficient lighting, particularly when considering a new design. Consider How? Why? Illuminance Check the lux levels (lumens/m2) needed for different areas. Appendix B is a guide. Actual measurements can be made with a lux level meter. The amount of light needed will depend on what activity is taking place in the area and regulation. Consider how lamps age and work out how long they are expected to be in place. Old lamps emit less light for the same amount of energy. If lamps will be in place for a long time, illuminance may be affected. Efficacy Use Appendix A to check the lumens/watt value. The higher the number, the more efficient the lamp. The more light a lamp can produce, the fewer lights will be needed to meet needs. Colour rendering and temperature Check the Kelvin and Ra of the lamp. Appendix A and C can in the comparison of lamps. Choosing a lamp with poor colour qualities can have disastrous results in businesses where identification or matching is important, for example, food processing, textiles and retail. Lamp life Check the estimated hours of light. Appendix A has a guide. By measuring lamp life, you may find that a higher capital expenditure is justified. Choosing long-life lamps for areas which are difficult to reach, could save on the maintenance costs in replacing them less frequently. Ask suppliers about different control gear that might lengthen the life. High frequency control may extend the life of the lamp. Warm-up and re-strike times Use the information in the previous section as a guideline and talk to your supplier. If an application needs a quick warm-up or re-strike, such as security lighting, certain lamps will not be appropriate. Luminaires Identify which luminaires are available/ required for types of lamp, and check the light output ratio (LOR) of each. Luminaires affect the direction and output of light from the lamp. Choosing efficient luminaires can reduce the number of lamps needed.

13 13 Opportunities for energy savings There are many low-cost and no-cost measures you can employ to reduce your lighting bill, without adversely affecting working conditions. And by upgrading your existing lighting system you may save even more.

14 Reduce the need Even the best lighting design is at its most efficient when it is switched off. Reducing lighting levels and maximising use of natural, free daylight can save substantial sums of money and give building occupants greater control over their environment. Benefits of lower lighting levels Many businesses are over-lit, making the space uncomfortable and costing money. Working in areas with very high lighting levels for extended periods is difficult due to excess glare. Switch off unnecessary lights, perhaps providing task lighting for those areas that require it. Reduce the number of lights Corridors and other non-critical areas are often over-lit, so consider removing some lamps from their fittings. This is particularly straightforward if the space is lit with multiple fluorescent tubes redundant lamps can be twisted out of the fitting. Take care to ensure there is still sufficient light to satisfy health and safety requirements. If building use or layout changes, it is important to remove lighting that is no longer required. Check for and disconnect redundant lights such as those obscured by equipment or shelving. Controls should be located in the same room as lighting where possible. Make good use of natural lighting Most people prefer to work in natural light, so encourage staff to keep lights off where there is sufficient daylight. Ensure windows and roof lights are not obstructed and that they are regularly cleaned. If possible, angle blinds to reflect more light onto the ceiling or into the workspace rather than blocking the light completely. Decorating walls and ceilings in light colours will to reflect light more deeply into the building. Installing controls and lighting in zones can significantly reduce your lighting need. See page 19 for more information Energy-Efficiency Loans Small or medium-sized enterprises (SMEs) in England or Scotland and all businesses in Wales that have been trading for at least 12 months could borrow* from 3,000 to 100,000. Loans are unsecured, interest-free and repayable over a period of up to four years. There are no arrangement fees and applying is straightforward. All businesses in Northern Ireland* that have been trading for at least 12 months may be eligible for an unsecured interest-free loan. Visit *Subject to eligibility. Regional variations apply. 14

15 Good housekeeping and people issues The greatest potential resource in achieving lighting efficiency could be right in front of you your staff. Savings are easily achievable in all organisations and need not require any initial outlay. Many opportunities are within the control of staff which is an ideal way of involving people and raising awareness. Switch off policy Examples of posters and stickers available from the Carbon Trust A chiller door left open for 30 minutes a day wastes enough energy in a year to power a lighthouse for nearly 4 days. Close it and you ll make all the difference. A common problem in workplaces is that people are not sure which switches control which lights. Consequently more lights are left on when they are not needed. A simple and effective solution is to label switches with the areas they control. This will aid employees to select only those lights they need for the work being carried out, for example when working on an isolated industrial process or when a meeting room is not required. Lights in unoccupied areas can then be switched off. Download Office lights left on overnight use enough energy in a year to heat a home for almost 5 months. Switch it off and you ll make all the difference. Switch them off and you ll make all the difference. For more ways to combat climate change at work visit For more ways to combat climate change at work visit For more ways to combat climate change at work visit Make switching off lights an official policy. Then publicise the policy as part of an awareness campaign. One way to remind staff to switch off the lights is to place switch off stickers above light switches and posters around the workspace (right). Label light switches A photocopier left on standby overnight wastes enough energy to make 30 cups of tea. Switch it off Switch it off and you ll make all the difference and you ll make all the difference Switch it off Switch it off Energy wasted from open chiller door = 0.2kW x 30 minutes per day x 365 = 36.5kWh. Lighthouse 0.4kW x 24 hours x 4 = 38.4kWh. For full calculation see Photocopier standby = 0.042kW x 14 hours = 0.588kWh. Average cup of tea = 0.25 litres = 0.25kg. Energy used to make cup of tea = 0.25kg x heat capacity of water (4200j/kg/ C) x temperature rise (90 C - 20 C) = 73,500 joules = 0.02kWh kWh/0.02kWh = 29.4 cups of tea. For full calculation see Based on typical office floor area of 1500m using 18 x 70W (6ft T8 fluorescent tubes) x 14 hours x 365 days = kWh. Average annual energy use to heat a three bed semi-detached home = 16308kWh/12 months x 5 months = 6795kWh. For full calculation see The Carbon Trust is grant funded by the Department for Environment, Food and Rural Affairs, the Department for Business, Enterprise and Regulatory Reform, the Scottish Government, the Welsh Assembly Government and Invest Northern Ireland. Carbon Trust All rights reserved, March The Carbon Trust is grant funded by the Department for Environment, Food and Rural Affairs, the Department for Business, Enterprise and Regulatory Reform, the Scottish Government, the Welsh Assembly Government and Invest Northern Ireland. Carbon Trust All rights reserved, March The Carbon Trust is grant funded by the Department for Environment, Food and Rural Affairs, the Department for Business, Enterprise and Regulatory Reform, the Scottish Government, the Welsh Assembly Government and Invest Northern Ireland. Carbon Trust All rights reserved, March PFL308 PFL310 PFL306 PFL308 PFL310 PFL307 Switch it off Switch it off Turn it off and you ll make all the difference and you ll make all the difference Switch it off Switch it off and you ll make all the difference and you ll make all the difference Switch it Switch off it offturn it off Switch it off PFL338 PFL313 PFL313 Switch it off and you ll make all the difference Turn it off Close it Switch it off and you ll make all the difference and you ll make all the difference Switch it off Turn it off and you ll make all the difference Turn it off PFL338 Turn it off Switch it off Turn it off 15

16 Set controls Figure 10 The benefits of daylight blinds requirements will vary at different times and in different parts of a building throughout the day. Ensure that lighting controls are set to match demand, that is, when required during business hours. As well as considering control equipment, ensure that staff members understand the importance of switching off. Ensures light distribution deep into the interior Use blinds to maximise use of daylight Horizontal blinds can redirect daylight away from the work area and onto the ceiling or higher walls. This will brighten the space whilst eliminating glare, particularly if the walls are a pale colour. Doing this can also reduce the need for electrical lighting. Train staff not to use blinds just to block incoming light this often results in people turning lights on unnecessarily. Some daylight blinds have perforated blades to enable a view outside, which is often appreciated by staff. Reduces brightness at the window Protects from heat and glare Provides a view outside for staff Direct sunlight Diffuse overhead light Maintains the natural daylight spectrum 16

17 Staff involvement Staff members are crucial in making savings with lights after all they are the ones who use them. It is important to make sure that all are involved with an energy efficiency campaign in lighting. Here are some ways to get staff involved: Request feedback on problems, particularly on poorly maintained lights and other areas where lighting is causing discomfort or disagreement Find out what staff need, and what they like Involve staff in awareness campaigns, for example, in putting up posters or running inter-team competitions Run training in best practice and controls so that they can achieve comfortable and efficient conditions for themselves. Do not neglect training cleaners in the drive for efficient lighting especially if they work overnight. It can be very demoralising for staff to find that all the lights they switched off were left on again by the cleaners. Safety first! Tax incentives Always ensure that switch off policies do not interfere with emergency lighting or the provision of adequate lighting to maintain health and safety standards. Enhanced Capital Allowances (ECAs) enable businesses to buy energy efficient equipment using a 100% rate of tax allowance in the year of purchase. Businesses can claim this allowance on the investment value of energy efficient equipment, if it is on the Energy Technology List. The procedure for claiming an ECA is the same as for any other capital allowance. For further information please visit or call the Carbon Trust on Did you know? costs can be reduced by 20% by only using electric lighting when the space is occupied and when there is insufficient daylight. 17

18 18 Maintaining existing systems Making improvements to lighting efficiency does not have to involve expensive refurbishment just make the most of what you have. Cleaning schedule Check sensors Implementing a cleaning schedule as part of regular maintenance is the first step. Make sure the sensors are operating properly. One simple check is to obscure daylight sensors this should bring the lights on. Check timers on lights are showing the correct time and that the settings meet business requirements. Make sure these are altered when the clocks change during the year. Windows and skylights clear glass allows maximum daylight to enter the building. This can reduce the need for electric lighting significantly. Cleaning the glass is particularly important for city-based workplaces and industrial premises where high levels of pollution can cause a film of dirt to settle on windows. Luminaires light fittings can collect dust which reduces the light reaching the staff. Some designs are particularly prone to collecting dirt. Sensors clean controls and sensors to make sure dust is not obscuring them and limiting their effectiveness. Did you know? Without regular maintenance, light levels can fall by at least 50% in 2-3 years. Establish a maintenance programme Maintenance can reduce costs by up to 15% as well as improving light output and appearance. List equipment that should be maintained with notes on frequency of actions. Keep an ongoing schedule of maintenance activity to ensure nothing is inadvertently missed. Replace failing lights Maintenance is an excellent time to change for efficiency. Failing lamps and dirty fittings reduce the quantity (and sometimes the quality) of light that enters the room. As well as costing in terms of energy, this can lead to unnecessary use of task lighting, and even have safety implications. Top tip Always replace or remove fluorescent tubes that are not working. The ballast uses around 25% of the energy of a lamp and fitting for mains frequency lighting, and around 10% for high frequency lighting. Significant amounts of energy will still be consumed even when the failed tube is not lit, so removing it is important. Replace blackened, flickering, dim or failed lamps immediately. During any maintenance, consider if there are more efficient alternatives available. A maintenance schedule can be adapted to accommodate individual circumstances. For example, industrial premises may have many lights mounted at height (high bay). Replacing all of them at the same time ensures that all lights in an area are the same age and reduces the risk of failure. It can be cheaper to operate this way, especially if equipment is required to reach the lamps (such as a cherry picker).

19 Understanding and using controls Regardless of how efficient lamps are, energy is being wasted if lights are on when they are not required. There are various types of control available to maintain correct lighting levels and provide optimum light output whilst minimising energy consumption. Zoning lighting Larger work spaces have areas that require different levels of lighting. A solution to this is to create zones wherein separate lighting controls are installed. This allows lights to be switched off in certain areas independently. Zoning provides closer, more efficient lighting control which can improve local conditions and save on costs. Zoning should be considered when there are: Different occupancy patterns Different lighting requirements depending on the task being carried out This type of zoning can also be utilised effectively for larger zones, switching lights off that are close to windows whilst dimming those further in to provide adequate light levels. This enables occupants to make the most of natural daylight without leaving those spaces further away from windows in shadow. As a result, less lighting is used which reduces energy consumption and additional heat generated by the lights and, therefore, less cooling is required. Figure 11 Switching in parallel Daylight 10% Daylight 5% Daylight 2% Windows Daylight 20% Switching in parallel One way to arrange lighting zones is to wire switches to control lights that are parallel to windows. See Figure 11. Windows Different levels of daylight provision within a building. As an example, a small room with a single light might be considered as a single zone. Where this room is lit by two lights, separate switching can create two zones, for example allowing the light nearer the window to be switched off when daylight is sufficient. This can save 50% of the lighting energy for that room when such conditions permit. circuit 1 circuit 2 Control lighting circuit 1 separately from lighting circuit 2 so when it is bright outside, only circuit 2 needs to be switched on. This can result in significant savings. 19

20 Creating different occupancy zones If part of a building has varying occupancy levels, consider zoning the lighting in these areas. This will allow lights in empty sections to be switched off without affecting areas where people are still present. If several small areas within a building operate at different times to the main building occupation, consider relocating staff into the same space and controlling this separately. Other forms of control, such as time controls or sensors, can be applied to each zone separately. The diagram opposite shows how occupancy and building layout might suggest some zones in an open plan office. Zoning like this will mean that lights on the window side can be turned off when daylight permits. Other zones could be switched off when individuals are not in to require them. The lights at the top right zone could be switched on if the trees block the daylight at certain times of the day. Did you know? Automatic lighting controls can save 30% on costs. Figure 12 Example of zoning in an office Windows 20

21 Time control Occupancy control Case study A seven-day timer will allow users to determine different operating times for lighting throughout the week. It can also automatically switch lights off when the building is likely to be unoccupied. To ensure occupant safety, these controls should be supplemented with occupancy sensors and a manual override to prevent anyone being left in the dark if they are working out of core business hours. Occupancy sensors to ensure lights only operate when there is somebody there to require them. Sensors can achieve savings of up to 30% on lighting costs. These sensors vary in range and ability to detect activity through furniture, machinery and other obstacles. They are often used in external security lighting to switch them on when a presence is detected. Occupancy sensors can also be used in conjunction with a manual switch to turn off lights after a set time period, again where no movement is detected. However, this option is not always suitable for areas where occupants are still for significant periods, such as offices, hospital wards or school halls where exams take place. control in a hospital Timers can be particularly useful in the control of slow-response lighting such as that usually found mounted at heights. These take time to warm up (and cool down) so should not be switched on and off too often during building occupation, but they should be turned off when the building is empty. Time delay Time delay switches installed in storerooms and cupboard spaces that are not continually occupied will prevent lights being left on accidentally. For larger spaces, it is better to install a manual switch with presence sensors to ensure the lights only go off after a set period of time in which no movement has been detected. Photo-electric cells Light sensors, or photocells can be used to switch off artificial lighting when there is sufficient natural daylight. As daylight hours vary throughout the year, sensors to provide closer control and thus, substantial savings. They can be particularly useful for external lighting and can pay back their costs in less than a year. Both occupancy and daylight controls can be combined with time switches to provide even bigger savings. Photo-electric controls can also enable dimming of fluorescent lamps. This application is only possible for newer lighting installations that are switched in parallel to windows and have high frequency fittings. 21 aintenance staff in a hospital noticed that M the lights in the toilets and cleaning areas tended to be left switched on. To combat this, they replaced traditional switches with intelligent lighting that incorporates passive infrared motion detection. Lights now come on when someone enters the room, but go off automatically when motion has not been detected after a preset period. This measure not only saves energy, but s in the prevention of the spread of disease as staff no longer need to touch switches.

22 22 Upgrading and refurbishment Upgrading a business s lighting system offers better control, lower running costs, less maintenance, and improved light quality. Lamps T12, T8 and T5 tubes The table overleaf shows a summary of common work spaces and appropriate lamps. It can be used to identify the most efficient and appropriate alternative lighting system. Almost any 1.5 inch (T12) diameter fluorescent tubes that flicker on start-up can be replaced instantly with slimmer 1 inch diameter (T8) tubes. If replacing luminaires, consider those that will take the even more efficient T5 fluorescent tubes. Of the many possibilities, this section focuses on specific tips for fluorescent lamps, being a very common and efficient form of lighting for most businesses. Install CFLs Recent developments in the performance of energy saving bulbs mean that they can be used in place of the more traditional (tungsten) light bulb in almost every application. Compact fluorescent lamps (CFLs) will last up to eight times longer than their tungsten comparators, meaning there is less time spent replacing them. For a similar light output to tungsten bulbs, they use only 20 25% of the energy. Instant start-up is now available and many new light fittings are being produced that can accommodate larger lamps. Dimming is possible if high frequency control gear is specified. Triphosphor coating Specify triphosphor coating on all new fluorescent tubes. These provide a more natural, brighter light for the whole life of the tube. The graph below shows how triphosphor coated fluorescent tubes remain brighter than other fluorescent tubes for a longer average life. Luminaires It is pointless to have an efficient lamp and use an inefficient fitting. Consider the selection carefully because not all luminaires of the same category emit the same amount of light (see page 11 for information on light output ratio). Many excellent luminaires exist. Particularly recommended are those using efficient optics, such as reflectors (see the top tip on page 23) or prismatic glass which maximise light output. When considering lamps, also consider the way the luminaires will direct light and whether they will need to be cleaned often to keep the light quality at the level required. Careful selection can mean fewer luminaires are needed for a project, saving energy and cost. Figure 13 Brightness over time of fluorescent tubes 100 % of initial brightness Triphosphor-coated Traditional fluorescent Operating hours (thousands)

23 Table 2 Appropriate lamps by sector Internal Space use Recommended lamp type Offices Triphosphor tubular fluorescent, compact fluorescent, low voltage tungsten halogen (use sparingly) Factories Triphosphor tubular fluorescent, high pressure sodium, metal halide, inductive Hotels Triphosphor tubular fluorescent, compact fluorescent, low voltage tungsten halogen (use sparingly), LED Hospitals Triphosphor tubular fluorescent, compact fluorescent Retail Metal halide, white sodium, compact fluorescent, low voltage tungsten halogen (use sparingly), LED Leisure Triphosphor tubular fluorescent, compact fluorescent, metal halide, inductive Emergency directional LED Car parks High pressure sodium, metal halide, compact fluorescent Multi-storey car parks Triphosphor tubular fluorescent, compact fluorescent, metal halide, high pressure sodium Floodlighting Metal halide and high pressure sodium Feature Metal halide, high pressure sodium, triphosphor tubular fluorescent, LED Sports facilities Metal halide (4,000K+) External 23 Improve efficiency through high-frequency control Light flicker from discharge lamps such as fluorescent tubes usually operate on a normal 50Hz mains electricity supply, but this can cause flickering. In extreme cases, this can cause headaches and stress. Special control gear circuits runs the lamps at a higher frequency, usually 30kHz. Such gear has the added advantage of improved energy efficiency, and allows lighting to be dimmed. Top tip Fit mirror reflectors to save energy Fluorescent lights usually sit within one of two types of fittings: either within a plastic case designed to reduce glare (a diffuser) or one with mirrors within the fitting to reflect the tube light. Reflectors increase the light falling into an area for no extra electricity and therefore require lower wattage tubes or fewer tubes to obtain the same light output.

24 Specify high-frequency fittings How the use of daylight can be maximised High-frequency fittings reduce energy use and heat output, eliminate flicker and hum, extend lamp life and can allow dimming all of which can make a building more comfortable for staff and customers. Take care to ensure the fitting still provides the user with protection from glare. This is explained further in the box on page 23. How lighting will dim with age The most energy efficient design possible. Above all, the lighting designer should consider health and safety implications and ensure: Energy surveys Your company may qualify for a free energy efficiency survey from one of the Carbon Trust s expert consultants. Visit A safe and well-lit exit in the event of an emergency for high ceilings Avoid high wattage tungsten lighting in high bay applications they have very short lamp lives. Not only are they expensive and inefficient, but they will cost time and resources to replace them frequently. A better option could be discharge lighting (high pressure sodium or metal halide) to increase lamp life and reduce running costs wherever immediate start-up is not required. Considering new build or refurbishment When designing a new lighting installation, it is important to consider: The safety of the occupants How lighting can building occupants to carry out their tasks effectively In what ways lighting can create the right atmosphere for the business The building s architecture The costs of installing and operating the system 24 Elimination of any deep shadows that may hide obstructions Reduction or elimination of glare from a light source or reflection Rotating machinery can be operated safely (some electric lighting can cause rotating machinery to appear stationary) A safe and well-lit environment if potentially dangerous tasks are to be carried out. If planning to refurbish lighting, contact the Carbon Trust for free advice. You may be eligible for a loan, get with finding products that qualify for an Enhanced Capital Allowance (see Tax incentives box, page 17) or qualify for from a consultant. Did you know? Whilst it may not have any effect on energy use, installing the same type of lamp in the whole area will improve its appearance. Top tip To reduce the possibility of theft of lamps, consider changing standard bayonet or screw fittings to security fittings.

25 25 Next steps There are many easy low and no-cost options to save money and improve the operation of your lighting system. Step 1. Understand your energy use Find out what lighting you have, where it is installed and how it is used. Ask staff to report any lighting issues and act on any feedback. Check the condition and operation of lamps and fittings and monitor how the lighting is used over, say, one week to obtain a base case against which energy efficiency improvements can be measured. Step 2. Identify your opportunities Compile an energy checklist of your lighting. Walk round your building and complete the checklist at different times of day (including after hours) to identify where energy savings can be made. An example checklist is available. See Appendix D on page 29. Step 3. Prioritise your actions Draw up an action plan detailing a schedule of improvements that need to be made and when, along with who will be responsible for them. Short-term actions could include launching an awareness campaign and writing a usage policy; long-term plans could include planning a major refit of lighting controls and zoning the lights. Investigate interest-free loans and ECAs for new equipment. Step 4. Seek specialist It may be possible to implement some energy saving measures in-house but others may require specialist assistance. Discuss the more complex or expensive options with a qualified technician. Some organisations qualify for tailored consultancy from the Carbon Trust, and all are welcome to get advice from the advice line. Step 6. Continue to manage your business for energy efficiency Enforce policies, systems and procedures to ensure that your business operates efficiently and that savings are maintained in the future. Related publications The following publications are available from the Carbon Trust: Fact sheets (GIL126) How to install lighting controls (GIL153) Step 5. Make the changes and measure the savings Implement your energy saving actions and measure against original consumption figures. This will assist future management decisions regarding your energy priorities. How to refurbish your lighting (GIL154) Management guides Creating an awareness campaign (CTG001) DVDs Switch to saving: Heating and lighting (CTX603)

26 26 Glossary Ballast A component of conventional control gear. It controls the current through the lamp, and is used with discharge lighting, including fluorescent, sodium, mercury and metal halide lamps. The term is sometimes used loosely to mean control gear. Also called a choke. Building lighting The lighting of the main surfaces of a building, particularly walls; the surround to work stations and in large rooms, the ceiling. Building lighting design will depend on the required visual amenity and the architectural design, and should be considered alongside the design of task lighting. Choke Alternative name for ballast. Colour rendering An indicator of how accurately colours can be distinguished under different light sources. The colour rendering index compares the ability of different lights to render colours accurately with the Ra measurement of 100 being ideal. Colour rendering properties of a light source are specified by the colour rendering index (CRI). See also colour temperature and CRI. Colour temperature Also known as colour appearance, the colour temperature is the colour of white the light appears. It is measured in Kelvin, and ranges from 1,800K (very warm, amber) to 8,000K (cool). 6,500K is daylight. There are many colours of white available. For general use these are: a warm white (2,600 to 2,700 degrees Kelvin), a medium white (3,000 to 3,500 degrees Kelvin) and a cool white (blue-y 4,000 degrees Kelvin). Diffuser A translucent screen used to shield a light source and at the same time soften the light output and distribute it evenly. Control gear A package of electrical or electronic components including ballast, power factor correction capacitor and starter. High-frequency electronic control gear may include other components to allow dimming etc. Efficacy (luminous efficacy) The ratio of light emitted by a lamp to the power consumed by it, that is, lumens per Watt. When the control gear losses are included, it is expressed as lumens per circuit Watt. CRI Colour rendering index has been defined by the CIE (Commission Internationale de l Eclairage). The CRI is specified for individual colours, Rj, or, for eight reference colours, Ra. Good colour rendering equates to a high CRI (CRI 100 = daylight), poor colour rendering equates to a low CRI. See also Ra, colour rendering, colour temperature. Filament lamp A lamp which produces illumination by heating a filament until it glows. Discharge lamp A lamp which produces illumination via electric discharge through a gas, a metal vapour or a mixture of gases and vapours. Illuminance The amount of light falling on an area, measured in lux. 1 lux is equal to one lumen per square metre.

27 Kelvin A measure of colour temperature for lamps. Kelvin is oc Light output ratio (LOR) The ratio of the total amount of light output of a lamp and luminaire to that of just the bare lamp. Luminaire A light fitting and lamp including all components for fixing and protecting the lamps, as well as connecting them to the supply. Lumen Unit of luminous flux, used to describe the amount of light produced by a lamp or falling on a surface. Lux An international unit of measurement of the intensity of light. 1 lux is equal to the illumination of a surface one metre away from a single candle. Maintained illuminance The minimum illuminance averaged over the reference surface at the time maintenance has to be carried out (by replacing lamps and/or cleaning luminaires and room surfaces). Ra The colour performance of a lamp is described by its general colour rendering index (Ra) which defines its ability to show surface colours accurately. It is described by a number 100 is considered to be excellent, a value of 80 and above is good and appropriate for most situations where people are present. Where colour identification is important, a value of 90 or above should be used. Rated average lamp life The time when half the number of lamps in a batch fail under test conditions. 27 Re-strike The time taken for a lamp to illuminate after being switched off and then on again. Start-up The time taken for a lamp to illuminate after being switched on from cold. Task lighting The lighting provided for specific tasks within a lighting design. For example, task lighting design will depend on the particular tasks undertaken and the building lighting design. Universal operating position Refers to a lamp that can be oriented in any way without affecting light quality.

28 Lamp abbreviations Tungsten lamps Mercury lamps GLS General lighting service (incandescent lamps). MBF/U Used for standard mercury filled lamps, available in elliptical or internally silvered reflector types or with integral ballast. High pressure sodium lamps SON Used in this text as a general abbreviation for high pressure sodium lamps and would have either a T (tubular) or E (elliptical). Multi-vapour lamps SON-DL Used for SON deluxe lamps, which have an improved colour rendering. CMD Metal halide lamp which has a ceramic arc tube and retains its initial colour properties longer, therefore mainly eliminating colour shift. White sodium High pressure sodium lamp which achieves high Ra rating and around 2,500 degrees Kelvin. MBI/MH/HID/HQI/HPI Sometimes used to denote multi-vapour lamps. LED Light emitting diodes and are presently available up to 5W in white and colours. 28

29 Appendices A. Lamp comparison table Lamp type Efficacy (Lumens per Watt) Poor Excellent Average life (thousand hours) Poor Excellent Colour rendering (Ra) Poor Installation costs Running costs Excellent B. Examples of recommended standard maintained illuminance Maintained Illuminance Lux Task/Activity/Interior 5 Healthcare ward night lighting 20 Unstaffed gangways 50 Remote operated processing, person-sized underfloor tunnels, cellars, underpasses, healthcare corridors (night), cable tunnels, indoor storage tanks 100 Circulation areas, entrance halls, corridors, rest rooms, store and stock rooms (not medical), healthcare wards (general), changing rooms, auditoria 150 Stairs, escalators, travelators, loading ramps/bays, staffed gangways, medical stores 200 Toilets, foyers, lounges, plant rooms, switch gear rooms, turbine halls, archives, library bookshelves, healthcare corridors (day), monitoring automatic processes, dining rooms 300 General machine work, manufacture and assembly (rough), retail sales area, packing and handling areas, welding, office (lowest), reception desk, filing, exhibition general lighting, sports halls, teaching areas Tungsten filament low very high Tungsten filament (long life) low high Tungsten halogen high Tubular fluorescent halophosphate low low Tubular fluorescent (triphosphor and multiphosphor) low low 500 First aid rooms, laboratories, kitchens, writing, typing, reading, data processing, CAD workstations, conference/ meeting rooms*, offices (highest), switchboard, post room, medium machine work and assembly, general inspection areas, control rooms, retail till area, hairdressing CFL low low 750 Grinding and engraving, fine machine work and assembly, critical inspection and repairs, paint spraying and polishing, technical drawing, ceramic decoration, meat inspection, chain stores Low pressure sodium moderate/ high high low High pressure sodium moderate/ high low Metal halide moderate/ high low moderate low/ moderate Mercury Poor Excellent Poor Excellent 0 20 Poor C. Colour temperature of different lamps Comments D. Action checklist Action Progress Reduce the need Colour temperature in Kelvin 9000 At floor level Reduce lighting levels in over-lit areas 8500 Seek opportunities to use daylight 8000 Decorate walls and ceilings in light colours to reflect light in building Northlight/blue sky Where appropriate, remove fluorescent tubes from multiple tube fittings in corridors and non-critical areas 7500 Remove redundant lights that are no longer required 7000 Overcast sky Good housekeeping and people Make switching off lights an official policy 6500 More guidance available for display-screen equipment. Can be task lighting. Label light switches 6000 Set controls appropriately in line with time and location of lighting requirement *Should be controllable Summer sunlight Train staff to use blinds to maximise daylight Cool white fluorescent tube Healthcare examination and treatment, colour inspection, precision decorative grinding and hand painting, precision assembly, quality control, typesetting, gauge and tool rooms, retouching paintwork, cabinet making For inspection: correlated colour temperature 4,000K Electronic workshops, testing, adjusting: work with precious stones, watchmaking, hand tailoring, precision assembly, fine work and inspection Mostly task lighting Steel and copper engraving, assembly of minute mechanisms, finished fabric inspection Directional task light Metal halide lamp 5000 Involve staff raise awareness, train for best practice, invite feedback Maintain existing systems 4500 Establish a cleaning schedule, including windows, skylights, luminaires and sensors High pressure mercury lamp 4000 Tungsten halogen lamp 3500 Intermediate white fluorescent tube 3000 Warm white fluorescent tube Check sensors and timers on lights, making sure they are altered when clocks change Replace failing lamps and yellowing diffusers immediately, considering if there are more efficient alternatives available Replace all the lamps that are difficult to reach at the same time to reduce the time spent on maintenance overall 150W Tungsten lamp 40W Tungsten lamp Excellent Low pressure sodium lamp (SOX) Candle 1500 To start saving energy and reducing your costs now, download and print our lighting action checklist. Download Download Download Download 29

30 Go online to get more The Carbon Trust provides a range of tools, services and information to you implement energy and carbon saving measures, no matter what your level of experience. Carbon footprint calculator Our online calculator will you Case studies Our case studies show that it s often easier and less expensive calculate your organisation s carbon emissions. than you might think to bring about real change. Interest free loans Energy Efficiency Loans from the Carbon Trust are a cost Events effective way to replace or upgrade your existing equipment with a more energy efficient version. See if you qualify. and workshops ranging from introductions to our services, to technical energy efficiency training, most of which are free. Carbon surveys We provide surveys to organisations with annual energy bills of more than 50,000*. Our carbon experts will visit your premises to identify energy saving opportunities and offer practical advice on how to achieve them. Publications We have a library of free publications detailing energy saving and workshops The Carbon Trust offers a variety of events techniques for a range of sectors and technologies. Action plans Create action plans to implement carbon and energy saving measures. * Subject to terms and conditions. Need further? Call our Customer Centre on Our Customer Centre provides free advice on what your organisation can do to save energy and save money. Our team handles questions ranging from straightforward requests for information, to in-depth technical queries about particular technologies. 30

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