Ctv049 Lighting

8/13/2019 Ctv049 Lighting

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LightingBright ideas for efficient illumination

Technology overview

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Preface

Reducing energy use makes perfect business sense; it savesmoney, enhances corporate reputation and helps everyone

in the ght against climate change.The Carbon Trust provides simple, effective advice to helporganisations take action to reduce carbon emissions, and theeasiest way to do this is to use energy more efciently.

This technology overview introduces the main energy saving

opportunities for lighting and demonstrates how simple actionscan save energy, cut costs and may increase prot margins.

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Contents

Cover im age supplied courtesy of Zumt obel


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IntroductionLighting is something that most of us take for granted. How often do we question theamount or quality of that light? Or how much it costs to run and maintain?

This guide sets out to explain the basics ofartificial lighting; the equipment, designprinciples and the effect it has on our workand leisure.

It is intended to inform a wide range of readersabout the importance of light; both naturaland artificial. In particular, it will help you tounderstand how to choose ar tificial lightingequipment that will deliver the most energyefficient solutions without compromisingon quality.

A better understanding of good lighting

practices helps when considering its directand indirect costs.

A bad lighting scheme is a complete waste ofenergy and is not sustainable. This guide willexplain why and help you to improve the lightingwhere you work, saving money and carbon. Supplied courtesy of Zumtobel

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The Importance of LightDening shape and form, light determines the way we think and how we interpret thespaces around us.

The quality of artificial lighting is one of the mostimportant influences on performance in thework place. Some 80% of our sensory input atwork comes through our eyes; compromisingour vision is, therefore, not an option whenconsidering energy efficiency measures.

It is vital to provide good quality lighting that isdesigned to match the tasks being under takenand to respect the needs of the occupants.

And it is not only the visual effects of lightingthat need to be born in mind; recent researchhas revealed that lighting has a clear impact on

our health and well being in the work place. Theright levels and the quality of light have beenshown to affect alertness and accuracy at work.

Lighting uses some 20% of the electricitygenerated in the UK; and over 75% of lightinginstallations are thought to be out of date andunable to meet current design standards.

The need to reduce carbon emissions presentsan opportunity to make lighting more efficientand more effective; so long as the right decisionsare made when selecting new lighting.

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Understanding lightLight travels at approximately 700 million miles per hour and from leaving the sun, it takesaround eight minutes to reach the surface of the earth.

Light is electromagnetic radiation. Light visible tohumans though is only a tiny proportion of thewhole electromagnetic spectrum as shown inFigure 1. In fact the visible part of the spectrumranges from just 350nm-780nm just 400nmout of over 5 million!

Just outside of the visible part of the spectrumlie infrared and ultra-violet light. These terms areprobably familiar and with special equipment, weare able to see these areas of the spectrum too.

Our eye-brain system is a highly sophisticatedsystem of data transfer. When light enters the

eye, we have a number of receptors whichabsorb the information they are receivingand pass information to our brain.

We have three receptors in our eye: rods, conesand ganglion cells. Rods detect shape and formbut are monochromatic. Cones enable us to seeand distinguish colour so someone who isreferred to as colour-blind has a deficiency ofcones. They can usually see colour but havedifficulty in distinguishing between somecolours, especially red and green.

The third receptor, the ganglion cell is a relativelynew discovery and this is entirely light-responsive.It doesnt aid our vision but does inform our brainwhether it is light or dark. This controls ourcircadian rhythm, our daily cycle of awake andasleep. Cortisol, our in-built stress hormone,responds to light and rouses us into a state ofalertness. Over the course of the day, the sleephormone, melatonin, secretes into our systemand generates a dip in our alertness around

lunchtime. Exposure to a high level of light atthis time, a walk in the sunshine for example,is enough to boost the cortisol levels againand we become alert once more.

More information about the effect of light onhealth and well-being can be found on page 11 .

Figure 1 Electromagnetic spectrum

Gamma

X-Ray

UV

Visible Light

0.0005Nanometres

Infrared

Microwave

Radio

250 500 10,000 5,000,0000.5Increasing wavelength

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Light & colour

There are two very important aspects of lightrelating to colour which are often referred tobut not always understood: colour temperatureand colour rendering. They are both propertiesof lamps but have very different meaningsand implications.

Colour temperature is the way that the colourappearance of a lamp is defined It is measuredon the Kelvin scale and is based upon thereaction of a black body radiator. Imagine placinga poker into a fire, as the temperature of thepoker increases, it changes colour. As it starts towarm, it glows red, moves through orange andyellow and eventually appears almost blue-whiteat a very high temperature. The Kelvin scale ofcolour temperature reflects these appearancesand we refer to low colour temperature as beingwarm in appearance and high colourtemperature as cool in appearance.

Colour rendering is the term used to definethe ability of a lamp to show colours effectively.For example, when buying clothing, items canlook like one colour in the shop and then a quitedifferent one at home. This will be due to thedifference in colour rendering properties of theshop and your home lighting.

Some lamps are able to render colours perfectly,exactly as they would be seen in natural lightbut others have very poor colour renderingproperties. For example, High Pressure Sodiumlamps are highly efficient light sources but havevery poor colour rendering.

Figure 2 Colour temperature

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The colour rendering properties of lamps aremeasured using the Ra Index. This relativelysimple index ranges from 1 to 100 with an Ra

of 100 being perfect. Figure 3 illustrates howdifferent Ra index values affect the appearanceof colours.

Although good colour rendering is not alwaysessential, it is important to have it above Ra80in most interior spaces and in retail it is veryimportant. Externally, it is important for sportslighting but less so for street lighting.

Figure 3 Example of effect of colour rendering

Ra 25

Ra 50

Ra 75

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DaylightDaylight is the only freely available light source and yet all too often it is overlooked;well controlled daylight can provide a space with the best possible lighting effect,superb colour rendering, great user comfort and with zero cost or CO 2 emissions.

Research has demonstrated that daylight hastremendous physiological and psychologicalbenefits; bringing daylight into hospitals canspeed recovery and in schools it can help withconcentration and improve learning so why dontwe make more of it?

The argument is that using daylight successfullywithin buildings is not always simple orstraightforward; problems such as heat gainand glare from direct sunlight can be avoidedboth at the initial design stage and subsequentlywith shading devices. Daylight can be broughtinto spaces through roof lights, atria and lightguidance systems as well as windows. Viewour animation on how to maximise daylightin your buildings .

Lightly coloured walls and ceilings will aidthe distribution of daylight in rooms whilearchitectural light wells can aid daylightpenetration further into the building.

Artificial lighting is still needed of course,but by ensuring it is linked to the daylightavailability, it will be used most efficiently.

Successfully managing the balance of naturaland artificial light is key; whilst it is possible forartificial lighting to be completely off when thereis sufficient daylight in a space, considerationmust be given to what happens when that

changes; a sudden change of lighting levelthrough the artificial lighting all coming on (orturning off) at once, creates distraction anddiscomfort. So artificial lighting should bedimmed to balance the daylight and deliver aconstant light level for the users.

Figure 4 Switching in parallel

Daylight 2%Daylight 5%Daylight 10%

Daylight 20%

Lighting circuit 1 Lighting circuit 2

l li i i i l li i i i i ii i , l i i i . i l i

i i i .

Windows

Windows

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It is also important to consider the colourtemperature of the ar tificial lighting; daylightgenerally appears to be cooler than most

artificial light sources so this needs to be takeninto consideration when managing a mixtureof natural and artificial light because excessivecontrast may cause discomfort.

Figure 5 Effect of rooflights with automatic lighting control systemson total energy consumption

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0 5 10 15 20Rooflight area (%)

T o

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heatinglightingtotal

Did you know?

In a study in California it was found thatretail stores with roof lighting had higher

sales figures than those without.

Data is courtesy of the National Association of Rooflight Manufacturers

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Health & Well-beingLighting impacts upon our ability to work accurately and effectively.

The most important objective with lighting of aworkplace is to satisfy the needs of the staff bygiving them a comfortable and productive space.

By getting the lighting right, staff will be morecomfortable in their working environment andthey can become more productive. Of coursethe converse is also true so energy-savingmeasures which compromise the quality of thelighting is short-sighted and unsustainable.

Almost without exception the highest fixed costin any business is staff; salaries and associated

employment costs can be as much as 70% to abusiness, so although lighting represents a largeproportion of the electricity bill, the electricitycost in relation to staff is often very low.

Both natural and artificial light influence ourhealth and well-being; light directly affects ourmood and alertness and can also impact oursleep patterns.

The non-visual receptor in our eyes respondsto light and controls our levels of the keyhormones: cortisol, melatonin and serotonin.

Cortisol is commonly referred to as the stresshormone; it triggers our levels of alertness andenergy. When we have high levels of cortisol,we are alert and energetic; if these levels drop,we lose concentration.

Melatonin is the sleep hormone; high levels ofmelatonin help us to sleep; prolonged suppressedlevels of melatonin can cause insomnia.

Serotonin is our happiness hormone, our moodhormone. A deficiency of serotonin will adverselyaffect our mood. Serotonin is produced by thebrain when melatonin levels are low.

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The secretion of these hormones follows adaily cycle (shown in Figure 6 on the right) inresponse to the natural light-dark of the day.

If light levels are too low the sleep hormone,melatonin, is not suppressed and we dontproduce serotonin. This is why we can feelsleepy or a bit down in a dim environment; thinkof a how you feel on a grey, misty, Novemberday and compared with a bright, sunny, day. Thehigher light levels of the latter are stimulating ouralertness and happiness.

Research is continuing into the effects of both

light levels and the colour qualities of the lightbut results to date have indicated that benefits tomood, productivity, alertness and sleep pat ternscan be realised through adjustments to lighting.

Figure 6 Human circadian rhythm

cortisol

melatonin

alertness

body temp.

6 12 18 24 6 612 18 24

Data from Surrey University

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LampsLight sources are called lamps,rather than light bulbs, and each lamp type has differentcharacteristics which affect where and when they should be used.

The most impor tant three characteristics are theefficacy (how efficient the lamp is), its expectedlifetime and its colour rendering ability.

Artificial light can be created in different ways:Incandescent: where light is created by passingan electrical current through a wire so that itglows white hot. (e.g. Tungsten)

Discharge: the generation of light occurs withina gas filled envelope that is driven by an electriccircuit. (e.g. Fluorescent)

Solid state: light being generated at the junction

of a semi-conductor (e.g. LED)Although there are some other methods,these cover over 99% of currently used lamptechnologies.

Incandescent

Invented well over 100 years ago, incandescentlighting today is largely restricted to domestic

use and display lighting in shops, hotels andrestaurants. They have a short lifetime but dooffer good colour rendering. They are also in the most part easily dimmed.

Many incandescent lamps are currently beingphased out of the market because they areso inefficient.

However, there are some incandescent lampswhich are more efficient thanks to the addition

of halogen within the glass surrounding thetungsten element. In recent years, the lowvoltage versions of tungsten halogen lamps havehad their efficacy improved by around 30%.

Figure 7 Incandescent lighting

Did you know?

Lamps have to carry an energy-efficiencylabel (see Figure 8 ). Used on domestic

white goods for years, these displayclearly how efficient the lamp is.These are now being used on mostelectrical products.

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Discharge lighting

Most commercial lighting relies on a range oflamps that use glowing gas discharges and

phosphors to create light. Examples of lampsthat use this process are:

Fluorescent

Low pressure sodium

High pressure sodium

High pressure mercury

Metal halide

Ceramic metal halide.

Most discharge lighting is characterised by itsneed to warm up as they do not come oninstantly at full brightness. This is called the

strike time, which can vary from a few secondsto many minutes with some types.

Additionally, some types will not re-strike whenthey are hot, so if a lamp is switched off, it thencannot be turned back on immediately; thisaffects their controllability.

Fluorescent

By far the most common form of discharge

lighting, fluorescent lamps are supplied in tubularor compact forms.

The warm up to full brightness is quick; usuallyless than one minute. It is an efficient source,with typical efficacy around 80 lumens per wattand fluorescents have good colour renderingability. The lifetime varies over quite a broadrange, with compact fluorescents typically fromaround 6,000 hours while the tubular versions

start at around 12,000 hours, although there arelong life tubular versions rated at 70,000 hours.

Figure 8 EU Energy Efficiency Labelfor Lighting

Figure 9 Discharge lighting

Did you know?

Until recently lamps were labelled bytheir wattage, but this only tells us howmuch power it uses. Now, all lamps arelabelled by their light output, which isexpressed in lumens.

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Fluorescent lighting is also the most easilycontrolled of this type of lamp. They canbe switched on and off quite readily, and

with the right control gear they can besuccessfully dimmed.

Low pressure sodium

A highly efficient lamp, these are almostexclusively used in street lighting. These arethe familiar orange lights that seem to turn allcolours a dirty brown.

Although they are still the most efficient light

source they are progressively being replacedby other lamp sources because they take upto ten minutes to reach full output and cannotbe dimmed.

High pressure sodium

These lamps are easily identified as thebright golden street lights on many of ourmotorways; they are also often used in

warehouses and floodlighting.

They have a high efficacy of 125 lumensper watt and a lifetime around 20,000 hours.However, they have poor colour renderingand take a long time to reach full brightness.

As a result they are not easily switched ONand OFF; although, with the right gear theycan be dimmed to a limited degree.

High pressure mercury

These lamps are not commonly used in the UK.They produce white light with a bluish tinge.They are not very efficient and have poor colourrendering. Any installations using these lampsshould be considered for refurbishment.

Metal halide and ceramicmetal halide

This group of lamps of fers a highly efficient

source, typically 80 lumens per watt, in avery large range of power ratings.

They have colour rendering from Ra60 rightup to Ra90 or more and a lifetime typicallyaround 12,000 hours.

Image courtesy of Thorn Lighting

Figure 10 Metal Halide lamps used for sports lighting

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With a very wide range of lamp sizes, from20W through to 2kW, this is a very versatilelight source.

Often used in shops to highlight merchandise,they are also the mainstay of most sportsfloodlighting systems.

Solid state lighting

There are two types of solid state lighting:

LED Light Emitting Diodes

OLED Organic Light Emitting DiodesThe two types are quite different in formand in their potential applications.

Light Emitting Diodes (LEDs)

LEDs have been in common use for over40 years, most traditionally as the indicator ontelevisions when they are in standby mode.They are a very small, point source that can

appear to be very bright.

The light output of these devices has developedrapidly over the past few decades, making theiruse in commercial lighting viable. They have avery long life, typically 50,000 hours and their

efficacy is increasing all the time. Unlike otherlamps, LEDs are often integrated into the lightfixture so there is no lamp replacement. See

How to implement LED lighting (CTL164).

Organic Light Emitting Diodes (OLEDs)

Still very much in development as a light sourceso not yet viable for commercial use, OLED is aflat panel giving even, diffuse light.

Did you know?

There are some other lamps which have

not been described here but these form avery small part of the market. For moreinformation about all lamps, please visitwww.lif.co.uk

Figure 11 A comparison of light source efficacies

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1930 1950 1970 1990 2010 2020

Year

E f f i c a c y

I m / w

Low Pressure Sodium

Halo g enIncandescent

H ig h P re s s u re

S od i u m

Mercur y Vapour

M e t a l H a lid e

F lu o r e s c e n t

P o w e

r L E D

R o a d

m a p

( 0 9 )

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Dimmable HF gear can control the output of afluorescent lamp smoothly between 1% and100%. It requires additional control cabling tooperate the dimming function and the type ofcontrol gear driving the lamps is a significantinfluence on the choices that can be made whenintroducing a lighting control system.

The arrival of LEDs has not removed the needfor control gear; LEDs still need specific powersupplies, often referred to as drivers. Like othercontrol gear, they are required to deliver thecorrect voltage and current to the LED devices.In fact the quality of an LED driver can have asignificant affect on the LED performance.

Did you know?

Electronic control gear has significantlyimproved the efficiency of artificiallighting. However, the introduction ofDigital Addressable Lighting Interfaces(DALI) and the use of lighting controls

means that the standby and parasiticpower losses of this equipment mustalso be minimised.

Figure 13 Electronic ballast v. conventional (HID)

Power Consumption over lifetimeSON-T 150W

Watts

200

175

166

Initial energy saving = 3-4%

Annual saving based on (0.08 p//kWh 4400h)

Power

150W

Avg. saving

16-17%

Annual saving

12-13

Hours

Ballast conventional

Ballast electronic150W lamp

Data courtesy of Philips Lighting

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LuminairesWhilst lamps are the light source, these are housed in xtures called luminaires.

There is a huge range of luminaire types anddesigns, each with their own characteristics.It is helpful first to understand the componentswhich make up a luminaire and how energy

is used by these.

There are five principle components in aluminaire: housing, control gear, lamp holder,lamp and reflector. Some luminaires willalso have a diffuser.

In most luminaires, not all of the light emittedby the lamp is emitted by the luminaire.This is due to losses caused by inter-reflectionand absorption.

Figure 14 Line drawing of luminaire showing components

Lamp

Lamp holder

Housing

Reflector

Control gear

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We can measure the effectiveness of theluminaire performance by comparing the totallight emitted by the luminaire with that of thebare lamp. This is referred to as the Light OutputRatio (LOR). The higher the LOR, the better theluminaire performance.

Each type of luminaire will have differentperformance characteristics but the LOR willalso vary from manufacturer to manufacturerdepending upon the optical design and alsoquality of materials used.

Material within luminaires which directs the

light beams can vary in its reflecting ability from0.5 for a satin chrome material to 0.9 for analuminium material with a silver coating so theLOR in luminaires using these materials willvary enormously.

The most typical luminaires used in commercialproperties can be summarised as:

Modular

Downlights

Pendants

Spotlights

Wall lights.

On the following page is a summary of theseluminaire types, their typical performance andcommon application areas. It is worth noting atthis stage though that some luminaires aredesigned for a specific purpose and utilisingthem more generally is not advisable.

The requirements for lighting offices and otherareas where display screens are used, needcareful treatment and luminaires should bedesigned to avoid glare onto the screen whichwould affect the users.

Equally, ensure that there are high levels of

visual comfort in the space by illuminating thewalls and ceilings so that the users whole visualfield is considered and not just the desk. Theseoffice luminaires are often inappropriately usedin other areas such as retail environments.

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Figure 18 Pendants

Mounting: SuspendedLamp types: Fluorescent, Metal Halide, HPSLOR: 0.5 0.9Applications: Office, Industrial, Retail

Figure 19 Spotlights

Mounting: Surface, TrackLamp types: Metal halide,

LED Tungsten HalogenLOR: 0.8 1.0Applications: Retail

Figure 20 Wall Lights

Mounting: Recessed, SurfaceLamp types: CFL, Metal halide, LEDLOR: 0.4 0.6Applications: Office, Circulation

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Figure 15 Modular luminaires with reflector

Mounting: Surface, RecessedLamp types: FluorescentLOR: 0.6 0.9Applications: Office, IT areas

Figure 16 Modular luminaires with diffuser

Mounting: Surface, RecessedLamp types: FluorescentLOR: 0.5 0.9Applications: Office, Retail

Figure 17 Downlights

Mounting: RecessedLamp types: CFL, Tungsten halogen

Metal halide, LEDLOR: 0.6 0.9Applications: Circulation, Retail

Image courtesy ofThorn Lighting



Image courtesyof Zumtobel



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22Lighting

Lighting controls: overviewLighting controls can make huge reductions in energy use, usually between 30%and 50% in a typical ofce environment.

It does not matter how efficient a luminairemight be if its use is uncontrolled; there willstill be waste, avoidable costs and unnecessaryCO 2 emissions.

Lighting controls are the key to managing theuse of light and to ensure that the right light isprovided in the right place and at the right time.

Artificial lighting can be switched off or dimmed,both when there is sufficient daylight and whenthere is no-one there to benefit from its use. Thelight level may also be varied according to theneeds of a task or activity. Properly appliedlighting controls facilitate this and ensure thatthere is no unnecessary use of electricity.

Automated functions should be combined withuser controls to optimise performance; light andmovement sensors can monitor daylight andoccupancy and a time clock can manage overalloperating hours; but giving users of the space

: l i

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23Other

Lighting

Lighting

Heating

Industrial

18Other

Catering

Office Equipment

Cooling andVentilation

Hot Water

Heating

Retail

Lighting

Heating

154 4 4 3 3 2 1 Total = 106

Other

Office Equipment

Miscellaneous

Healthcare

Sports

Government Estate

Further and Higher Eductaion

Transport/Communications

Public Offices

Heritage and Entertainment

Heating

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Lighting

Catering

Schools

Heating

9Other

Catering

OfficeEquipment

Lighting

CommercialOffices

Cooling andVentilation

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Lighting

Catering

Heating

Hotels, Inns &Restaurants

Hot Water

Catering

Figure 21 Emissions by building type and end use (MtCO 2 )

Source: BRE, Carbon Trust analysis

Note: Industrial does not include industrial processesLighting accounts for 24 Mt CO 2

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23Lighting

some control is also valuable, we all like to beable to make decisions for ourselves.

These user controls must be easily understood

and conveniently located. Wherever there mightbe doubt then clear labelling should be employed.

The principle of combining user controls withautomatic management is to have an environmentwhere users switch lighting on but it is switchedoff automatically when it is no longer required.

Generally, were quite good at switching lightson when we go into a room but less so atswitching off when we leave. This approachneeds someone to make a decision to switchthe lighting on but then the controls automaticallyreduce the light level and switches off whenthere is sufficient daylight or when users leavethe room.

There is clear evidence that giving people morecontrol of their lighting conditions alsocontributes to their perception of comfort. Andin those buildings where there is a high ratio oflocal switches to lights less electricity is used.Comfort and lighting energy efficiency havebeen shown to go hand-in-hand.

Figure 22 User controls

Image courtesy of Philips Dynalite

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Lighting controls: techniques

Automatic lighting controls generally react tothree main stimuli:

Movement sensor occupancy control

Time clock timed schedule Light sensor daylight linking.

There are additional functions in some lightingcontrol systems but these are the principletechniques for reducing electricity use.

Motion sensors

Motion sensors monitor occupancy. They relyon three technologies to detect presence:

Passive infra red PIR

Ultrasonic detection

Microwave detection.

PIR sensors are the most common type usedin office spaces because they offer a goodcompromise between value and sensitivity.They can generally monitor smaller areas than

the other two methods which can be beneficial.

The location of a movement sensor is important;it must be able to see the activity that requiresthe light but not beyond that area. Many sensorsdo not work effectively because people passingclose by trigger the lighting to come on when itis not actually needed.

The table on page 25 was originally developedsome years ago by the Building ResearchEstablishment (BRE Digest 498 SelectingLighting Controls) in order to help peopleunderstand how lighting controls in any givenspace might be applied. A similar table appearsin the Building Regulations.

If a room is owned by a single occupant thenit is reasonable to pass responsibility for lightingcontrol to that individual. Once a space is sharedit then becomes more complicated because the

occupants may have different lighting needs. Thetype helps inform the application with regard tothe best choice of local controls.

Movement sensors can be used in two, different,modes presence and absence detection.Presence detection automatically brings on thelight as soon as it senses movement; andswitches the light off when the space is vacant.Absence detection lighting must be switched

on manually and the sensor then switches thelighting off when the space is empty.

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Time control

Whilst timed operation used to be an effectivemethod to control lighting based on predictedoccupancy levels in buildings, this doesnt fit sowell with modern, flexible working practices. To

have any chance of success there needs to be avery large number of local overrides that areeasily found and used. The need for these canmean that systems that rely only on scheduledswitching actually use more energy than amanually operated installation.

In modern, networked control systems timescheduling is now used to change the overalloperating mode. The behaviour of other controls

may need to be different at certain times of day.They do, however, remain vital in exterior lightingso lights are only on when it is dark outside.

Type of space Examples Controls

Owned Cell office, small workshop,consulting room.

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

Shared Open plan office, productionarea, ward.

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

Temporarily owned Meeting room, hot office,classroom.

Wall switch, scene plate, movementsensors; preferably in absence mode.

Occasionally visited Store room, book-stack, toilet. Wall switch (with time delay), movementsensor; auto operation OK.

Un-owned Corridor (open or closed), stairs. Remote manual or automatic operation,movement sensors; linked to workarea lights.

Managed Hotel lounge, museum, foyer,terminal.

Remote manual and automatic operation;time scheduling.

Table 1 Defining spaces and appropriate controls Figure 23 Some typical movement sensors

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Light sensors

The technologies used to detect light are, in themain, less important than the way they are used.

Light sensors are commonly used in two ways.They can be used to observe the external (natural)lighting conditions and hence be a reference levelfor the control system to act upon. Or they can bemounted in the ceiling to observe the lightingconditions immediately below.

The use of an outward looking sensor is usuallymade in applications where a lot of daylight iscoming into the building and the control function

is limited to switching only.

It works on the principle that the amount of daylightpenetrating the building will always be directlyproportional to the current ambient light. Thesystem then makes decisions about calculatedlevels of light in various parts of the building.

Downward facing, ceiling mounted light sensorsare usually used in office spaces where theintention is to use dimming control to integrate theartificial and natural lighting. As daylight increasesthe sensor automatically reduces the amount ofartificial light.

It is generally better practice to use dimmingcontrols when adjusting the lighting in responseto daylight. The light level in any space will bethe sum of the natural and artificial light. If thelight level was 1000lux, with 500lux providedby the artificial lighting, then a switch of f willhalve the lighting level and occupants maythink the light level is too low. The reactionwill be to restore the artificial lighting even ifit is not required.

Figure 24 Light sensors


Figure 25 Interior making use of good

daylighting

Image courtesy of Philips LightingImage courtesy of Zumtobel

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27Lighting

Lighting controls: applications

Lighting controls may also be categorised bytype and application:

Self-managed luminaire

Stand alone Room based

Scene setting

System.

Self-managed luminaire

Some luminaires are supplied complete with an

integral controller; this may be a movement and/ or light sensor. Sometimes called intelligentluminaires these products are suited to smallrooms and any application where each light maybe operated alone.

Stand alone

A stand alone lighting controller is usually aself-contained device that comprises a sensorand actuator. In most cases the two parts areintegrated into one physical package. Thesecontrols are independent from each other andwell suited to individual spaces like store roomsand toilets.

Room based

As the name suggests, these products havebeen designed to offer convenient control

schemes for one room or area. The mostcommon application is a classroom or meetingroom and the solution may contain a numberof components, depending on the size of roomand control needs.

Scene setting

When lighting controls are provided for theprimary purpose of comfort and ambience thena scene setting system is required. Frequentlythese products are manually operated and appearin lecture theatres, restaurants and hotels.

System

A lighting control system is usually a buildingwide application. That means all the lightingis effectively linked together and managedas a whole.

A full, networked, lighting control systemhas additional components to the sensorsalready described.

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Depending on the installation and application alighting control system may comprise:

A central supervisor

Area or zone controllers

Lighting Control Modules (LCMs)

Lighting control or Dimmer panels

Sensors

Control or scene setting switches.

Generally the components are designed to helpthe system to be included within the lightinginstallation infrastructure.

Their function and performance varies fromsupplier to supplier but their purpose is to makeeach system robust in use and easy to install. SeeHow to implement lighting controls (CTL161) .

Figure 26 Typical graphical user interface provided with a lighting management system

Image courtesy of Philips Lighting

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Lighting designWhat is lighting design and how does it t into the overall picture?

In its simplest form, lighting design is theselection and placement of the lighting withina space.

Ask any lighting designer what lies behind goodlighting design and youll get the same response:

Its the right light, in the right place, at theright time.

Arguably the most crucial of these, from anenergy management viewpoint, is the timing.It doesnt matter how efficient your lamp orluminaire is if it is on at 2am in an empty office.At the right time means it is switched off

when there is no need for it to be on.

Whilst lighting design is often optimisedfor new buildings, it is equally relevant forexisting buildings.

Lighting design draws together the fourkey components:

Lamps

Control Gear Luminaire

Controls.

Each of these components is explained ingreater detail elsewhere in this guide, but whilsteach component has its own level of efficiency,when they are brought together in a designedsolution, they will combine to provide even

greater efficiencies.

The lamp, control gear and luminaire combine toprovide the first of our answers to good lighting:the right light.

This takes the form of an appropriate luminaireoperating with its control gear and lampcombination to deliver the right amount of lightfor the purpose of the space.

The essential premise is that less light isrequired in a corridor than in an office, so gettingthe right amount of light is important.

The design of the layout of the luminaires willensure that the light is delivered in the right place.

It is important to only deliver light to where it isrequired; if a cellular office has one desk, thenthe light needs to be delivered to the desk and

not the surrounding carpet!

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How much light?

If the essence of good lighting design is aboutdelivering the right light, in the right place, at the

right time, then how do you decide on how thisis achieved?

The demands for light vary according to thepeople who are in the space and what tasks theyare completing.

In order to decide how much light you need andwhere you need it, ask the following questions:

Who is using the space?

What are they doing?

When will they be there?

How long will they be there?

Lets first address the question of who is usingthe space.

The reason it is important to know this isbecause our eyesight deteriorates with age.

Irrespective of other eye conditions, the visualability of a 10-year old child is hugely heightenedwhen compared to that of a 50-year old.Because of this, younger people need less lightto perform the same task.

More often than not, there will be a mix of ageranges in any given space. This is true, albeit todifferent degrees, whether it is an office or aschool and this variance may change during thecourse of the day.

For example, a school may be used predominantlyby children for most of the day but by adultsattending night classes in the evening.

Knowing who is using the space will help usdecide on the lighting requirements, in theexample of the school, we may need to allowfor the lighting to be changed.

Figure 27 Lighting left on in an empty office

Did you know?

The delivery of light at the right timecomes entirely down to the lighting

controls and these can ensure thatimages such as the one above donot occur.

Figure 28 Multi-functional lighting required

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The second question is arguably the mostimportant, the one which addresses the tasksin hand. The reason that we need to know this isbecause our demand for light varies with whatwe are doing. Walking down a corridor is a muchsimpler visual task than reading a book. In anoffice, we might need less light to look at acomputer than to read a printed report.

Detailed guidance for the lighting level requiredfor different tasks can be found in the Societyof Light and Lightings Code for Lighting.

Objectives & considerations

Whilst establishing the right light level for theapplication is an important part of the lighting

design process, there are other key objectivesand constraints to consider.

We may wish to add some lighting purely forvisual interest. This might take the form of walllights, spotlighting or even the inclusion of colour.

Whilst it may be considered to be superfluous,particularly in an energy context, visual interestcan prove a valuable additional benefit for thepeople who use the space.

People generally prefer to sit in front of awindow and although the view itself may not bespectacular, the interest created allows our eyesto relax and regenerate.

Additional lighting to create visual interest canachieve the same objective and this variety canreduce eyestrain and headaches.

More information on this intangible benefit canbe found on the next page.

However, one of the biggest hurdles we oftenface in the design process is that of thearchitecture of the space.

We can look ideally at a combination of lightsources and luminaires which we might want toinclude as part of the solution but invariably wehave to fit the solution around the ceiling type,layout and other features such as pillars.

Many buildings now have suspended ceilingswith 600mm x 600mm ceiling tiles and whilstthese enable all the building services to beconcealed, they can start to dictate lightingdesign to the detriment of the users.

At all times we must be mindful of the demandsof the people in the building that we are lighting. In

some older buildings, concrete slab ceilings are moreprevalent and this can lead to restrictions with wiring.

It may appear cumbersome to replace existingwiring arrangements but it should still beconsidered as the benefits of making a deeperrefurbishment can more than outweigh the costand inconvenience.

Figure 29 Lighting levels required to performa task vary with age

0

14

12

10

8

6

4

2

0 10 20 30 40 50 60 70

Age (years)

L i g h t r e q u

i r e m e n

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Figure 30 Wall lights provide visual interest

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Rather than considering the building architectureas inhibiting, we need to embrace it, adding walllights to pillars, creating opportunities with theceilings for additional details such as covelighting and utilising the flexibility of lay-in ceilinggrids to their maximum scope.

What we must ensure at this stage is that weare using the right luminaires to fit all theobjectives and constraints.

In the detail

It is important to create visual interest in anyspace, but particularly on the walls, for thecomfort of the users of the space.

Many people will experience eyestrain whenworking at a screen for long periods of time,in fact concentrating on any specific task fortoo long will cause the same effect.

In addition to the benefits for the human eye-brainsystem in creating a relaxing environment, a balance

of light on walls and ceilings in relation to the task isalso important from a contrast point of view.

Being exposed to a bright, uniform lighting level,whether it is a computer screen or an accountsledger, will cause further strain to the eyes.

If you have ever watched a film on televisionwith no lights on, you will know that thedifference between the bright screen and darksurrounding walls means the eye is exposed totwo hugely contrasting light levels and trying toadapt between these is dif ficult.

However, whilst creating an environment withvisual contrast can be beneficial to users, weneed to be mindful of the effects of inadvertentcontrast within a space.

One area which is often overlooked is the colourtemperature of fluorescent lamps; all too of ten

we see occurrences of luminaires containing amixture of different colour temperature lampsand rather than creating a comfortable andrelaxing environment, this variance can bedistracting to the people working under it.

A consistent approach in lamp type and colourtemperature selection can ensure that the lightingappears the same visually in all areas of a building.This can help to develop a coherent maintenance

programme as well as potentially reducing cost ofmaintenance through the possibility of bulkpurchasing of replacement lamps.

The key element of the lighting design process isthe selection of luminaires, lamps and controls tosuit the application, the architectural demands ofthe space and the people that work and live in it.

Figure 31 Light dark adaptation

Did you know?Light-dark adaptation is found in manysituations walking from bright sunlightinto a dark room, driving through a tunnel.

These extremes of brightness cause ahuge loading on our eye-brain systemto adapt quickly and the same is true,even if in less extreme circumstances,in most workplaces.

Creating a good balance of light onthe task whatever that task is thesurrounding area and our overallvisual field is crucial to user comfort.

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Although the lighting will always be consideredfor any new construction project or majorrefurbishment programme, it may also warranta dedicated make-over, especially forolder installations.

This section briefly outlines some of the main

considerations and principles that should befollowed when undertaking a project.

Legislation

There are over 30 European Standards whichaffect lighting in the UK. These cover a wide range

of subject areas but the most relevant one isEN12464 which covers the lighting of workplaces.No European Standards are mandatory and thereis no legal requirement for lighting other than thatit must be suitable and sufficient.

The Health & Safety Executive publishesguidance on minimum lighting levels and thiscan be downloaded from their website .More detailed guidance can be found from

the Society of Light & Lighting.For new construction and significantrefurbishment projects, the lighting must complywith the Building Regulations. It should be notedthat these differ within the UK and therequirements for England & Wales differ fromboth Northern Ireland and Scotland.

For England & Wales, the section coveringlighting is Part L . In Northern Ireland, it is

Section F and in Scotland, it is Section 6of the Building Standards . These all coverthe conservation of fuel and power.

Maintenance

Before embarking on any new lighting project, it isworth first considering the maintenance of existinglighting and developing a schedule for maintaining

this and any new lighting. The effectiveness of anylighting installation can be compromised withoutregular maintenance. This includes cleaning ofluminaires, especially reflectors and paneldiffusers. A fresh lick of paint can also make theworld of difference, although dark colours shouldbe avoided as they do not reflect light.

New construction

A lighting scheme will be required as partof the original design.

Refurbishment

Lighting is often a significant element ofthe project. An opportunity to consider anew, more effective, lighting scheme.

Retrofit

A stand-alone project when the lighting in

a building is out-dated and/or inefficient.

Figure 38 Lighter paint finishes reflectlight better

Image courtesy of LPA Lighting

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When lamps fail, replacement is generally carriedout in two ways: spot replacing each one as it failsor bulk replacement. Which suits your own situationwill usually depend on the size of the premises and

ease of access but a one-off bulk replacement in anolder installation may be worth considering.

Interior applications

If you have established, through this guide, thatyour lighting is out-dated or inefficient, then nowis the time to consider your options.

There may be pressure to opt for a quick win and

there is some merit in this, but it is worthconsidering a long term solution.

The two case studies following describe someof these solutions and of course, the primaryconsideration may be one of cost. However, youshould consider not only the capital investmentbut also the associated running costs and longterm benefits of each solution available.

The main consideration should be one of a returnon investment, not just based on the cost of thecapital investment but in terms of the benefits,tangible and otherwise that can be realised.

Having a clear picture of the options available,their associated costs and dividends will helpthe decision making process.

Case studyJM Henderson

JM Henderson took a two-pronged approach to their lighting, refurbishing the officelighting and upgrading the factory lighting.

In the office areas, they retrofitted new high frequency control gear and modern efficientfluorescent tubes into the existing light fittings.

In addition to lower energy costs and longer lamp life, the environment was improved forthe staff as HF lamps do not flicker like the older ones.

In the factory they replaced the old sodium lighting with new luminaires containingfluorescent lamps. The old luminaires were mounted at high level and both the quality

and level of lighting on the workshop floor was poor.

The new lighting produces crisp white light and is suspended at a lower height so inaddition to increased light levels and lower energy use, they create a more productiveand safer working environment.

Project cost: 26,000Energy reduction: 53 MWhFinancial saving: 4,600CO 2 saving: 29 tonnes

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If you are considering a refurbishment of yourexisting lighting, it is helpful to know the scale ofthe opportunity that is available.

With most refurbishments, lighting is often only acomponent part of a larger programme of activitiesand there is merit in exploring every possibilitybefore making a decision.

Replacing luminaires with new, more efficient orsuitable ones is really just the first step. Controlsagain need to be a core consideration and althoughin many cases, both luminaires and controls can beupgraded without major re-wiring or impact onceiling layout, there may be additional long-termbenefits to further investment.

If the existing lighting isnt delivering the optimumperformance for your use, then incorporating alevel of re-design to the lighting scheme may reapgreater rewards. This is often the case withinherited lighting schemes, so if you make thisassessment before you proceed with any lightingupgrade, you may benefit greatly.

Case studyBoon & Sons

Boon & Sons applied simple lighting controls to existing lighting in communal areas ofshared office space with huge energy savings.

Tenants have access to the let office space 24-hours a day so lighting had been left on evenwhen the area was unoccupied.

They installed fast-reacting motion sensors to provide light when clients require it, haltingwasted energy and money lighting unoccupied areas.

The new motion sensors are in shared areas, such as kitchens, bathrooms, corridors andcommon rooms. Before they were installed, the 182 fluorescent lamps in these areas had

been on 24 hours a day, 365 days of the year.

Now, when someone enters one of these areas, the sensors activate the lights and theystay on for as long as it remains occupied.

In addition to the energy savings, lamp life is prolonged and maintenance is reduced.

Project cost: 5,200Energy reduction: 36 MWhFinancial saving: 3,600CO 2 saving: 20 tonnes

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Case studyMaxim Logistics

Maxim Logistics replaced outdated fluorescent lighting with new,more efficient fluorescent luminaires and added lighting controlsto reduce energy consumption by 40%.

By installing HF dimmable fluorescent luminaires, Maxim hasbeen able to halve the number of luminaires in its mainwarehouse, without comprising the working environment.

Where there had previously been eight luminaires in each of theaisles, there are now just four. Two are on permanently, while theother two are lit at 10% with motion sensors to boost the light to75% when the space is occupied.

Although there are fewer luminaires, the warehouse is now actuallybrighter, even with the two lamps on the dimmed setting, makingthe warehouse feel brighter and improving working conditions forstaff, a great example of how saving energy can actually improve aworking environment rather than compromise it.

Project cost: 60,000Energy reduction: 200 MWh

Financial saving: 22,200CO 2 saving: 114 tonnes

Case studyHenderson Spar

A new lighting design with lighting controls for this convenienceretail outlet delivers light when and where its most needed. Thetotal solution delivers a 25% energy reduction.

A new lighting scheme was designed for a pilot store withluminaries positioned centrally above the aisles. The specifiedluminaires allow light to be directed more specifically to whereit is required.

The result is a s tore with increased light levels and an impressive24.5% savings in lighting energy costs. The shop has a storagearea and this area has been to fit presence detectors on each pairof luminaires. The PIR sensors detect the presence of staf f andautomatically switch the lights on for a set period of time.

Further controls have been added with daylight sensors to controltwo different lighting circuits in the forecourt canopy and site lighting.

The solution is now being rolled across all stores as the existinglighting nears end of life.

Energy reduction: 25 MWhFinancial saving: 2,250CO 2 saving: 13.5 tonnes

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For new buildings and for refurbishmentprogrammes which effectively allow for a blankcanvas, there is opportunity to integrate theartificial lighting with the architecture of the

building and to maximise the available daylight.

Controls linked to daylight puts less demand onthe electric lighting and can lead to significantreductions in energy use. Of course, considerationmust be given to the thermal impact, particularlyfor users by south-facing windows but horizontalblinds can reduce direct sunlight withoutcompromising daylight in the space.

Controls are the key to maximum efficiencies sothis is where it is crucial to consider who is going tobe using the space and when they will be there.With this in mind, the right controls can be installed.

Whilst the lighting expert on the design team canadvise on luminaires and light levels, it isimportant that the design meets your needs,whether that is in occupancy patterns or itemsbeing sold in a retail store.

Case studyNG Bailey

NG Bailey use an office relocation to maximise availability of natural light and reducedemand for artificial lighting.

Daylight penetration is maximised in the centre of the open plan area through the use ofroof lights and sun pipes into the toilet areas. Glare is controlled by occupant controlledinterstitial blinds.

The lighting in the main offices is a mixture of LED and high frequency fluorescent fittings,controlled by a DALI dimming system with absence detection and daylight sensing. Thereis one detector for every four workstations and each luminaire can be adjusted individuallyto maximise control.

Lighting in the cellular offices and meeting rooms is manually controlled with scene settinglighting in the larger meeting rooms controlled by hand held devices and touch screens.

As it a new building, it is difficult to quantify the financial impact of all of the sustainabilitymeasures that have contributed to this BREEAM Excellent project but NG Bailey believe thatthe operational savings will pay back any additional energy investments and the staff reportthat they love the new building.

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Exterior applications

So far we have focussed on mainly interiorapplications but it is important to recognise therole of exterior lighting in the overall picture.

The same philosophy of design the right light,in the right place, at the right time and theequipment available applies equally to exteriorapplications.

The main applications for exterior lighting are:

Car parks

Security

Architectural

Amenity

Sports

Street lighting.

Some of these might be regarded as moreimportant than others and the relevance of eachwill vary with each individual circumstance.

It is helpful to follow best practice and identifyenergy efficient solutions, irrespective of whetherit is for new or existing lighting scenarios.Arguably the most important consideration inexterior lighting is the impact it has in a widercontext and this brings light pollution into context.

Case studyLomond National Park

A new purpose-built headquarters allows the National Park to provide a sustainableBuilding in the heart of the community.

The building was designed to maximise the use of natural light using the advantages ofthe orientation of the site with most workstations located on the North East side of thebuilding to limit solar gain. The electric lighting is often not required as the daylight levelsare so high.

The electric lighting is controlled automatically via occupancy sensors as well as daylightlinking and the electric lighting only comes on if the light level falls below 250lux and alldesks are provided with task lights that can increase lighting levels to 500lux if desired.

The meeting rooms have occupant control with manual light switches and staff are happywith the provision for dimming the light levels for presentations and video conferencing.

No blinds were installed in the original plan, but have now been ordered for the two mainmeeting rooms and some of the windows in the open plan area to provide shading.

Staff have welcomed the sustainable approach and have reported greater contentmentand well-being.

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Light pollution can be categorised into threedistinct areas: light which is directed into thesky, referred to as sky glow; light which goesbeyond the area it was intended to (light spill)

and light which impacts onto other proper ties(light trespass).

You should keep all of these types of lightpollution to a minimum. In fact, the mostefficient exterior lighting will eliminate lightpollution entirely meaning that all of the lightis delivered to where it is required.

More detailed information on environmentalconsiderations for exterior lighting can befound in the Society of Light & LightingsFactfile 7 which can be downloaded for freeat www.sll.org.uk

As well as ensuring you are getting light in theright place, it is equally important to only light atthe right time and whilst it may be argued thatsome lighting, for safety or security for example,is on all night, the majority of applications shouldbe more controlled.

Architectural, amenity and sports lighting shouldall be timer-controlled with a cur few, as there islittle public benefit to this lighting beyondmidnight. Car park and security lighting can becontrolled effectively with presence detectorswhich could be combined with time clocks.

For street lighting, there is the opportunity withnew technology to have lower light levels atsome times of night which can respond to thetraffic flow.

Exterior luminaires are usually sealed units inorder to protect them from water damage, soretrofit lamp & gear solutions are not usually aviable option.

However, for existing installations, the latesttechnologies and improved luminaire designoffer opportunity for energy savings throughluminaire retrofit programmes.

LED technology is ideally suited to exteriorlighting and can be used in a variety ofapplications. Their small size enables smallerluminaires to be used and they are ideal forarchitectural enhancement of buildings.

In civic and residential areas, renewal ofluminaires, can not only reduce energyconsumption, but create a more pleasantenvironment for people. Under white light,

it is easier to identify peoples faces and theperception of safety is increased.

The introduction of exterior lighting can also beof benefit for example by creating pleasantand safer places for people to enjoy at night. SeeHow to implement external lighting (CTL162) .

Figure 39 Light pollution needs to be controlled


Image courtesy of JWSA

Figure 40 Buckingham Palace uses less than3kW on exterior faade lighting

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Case studyCentral Bedfordshire Council

The Council have piloted a trial of LED luminaires to replace traditional street lighting.

Traditional street lights are being replaced with LEDs to achieve significant wattagereduction, as well as reducing the maintenance burden of the highways team; 381 LEDlanterns were installed across two pilot areas one urban and the other semi-urban,using less than 50% of the installed energy load.

The instant light given by LEDs mean that full light output is achieved with no voltagespike or warm up period and using LEDs enables the standards to be met at a slightlylower light level than traditional sources would require.

As LEDs provide a more focused beam of light, they result in reduced trespass of lightbehind the column or into the sky although some residents felt preferred light onto thefront of their homes for security reasons.

The Council now hopes to begin replacing life-expired lanterns with modernLED alternatives.

Traditional LED

Number of columns 373 381

Annual electricity consumption 119MWh 54MWh

Annual electricity spend 10,710 4,860

Annual CO 2 emissions 64 tonnes 29 tonnes

Figure 41 National Theatre reducing lightingelectricity use in many ways

Image courtesy of Philips Lighting


Figure 42 White light is commonly used forstreet lighting

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Glossary

BallastA component of conventional control gear. Itcontrols the current through the lamp, and isused with discharge lighting, includingfluorescent, sodium, mercury and metal halidelamps. The term is sometimes used loosely tomean control gear. Also called a choke.

ChokeAlternative name for ballast.

Colour renderingAn indicator of how accurately colours can bedistinguished under different light sources. Thecolour rendering index compares the ability ofdifferent lights to render colours accurately withthe Ra measurement of 100 being ideal. Colourrendering properties of a light source arespecified by the colour rendering index (CRI).

Colour temperatureAlso known as colour appearance, the colourtemperature is the colour of white the lightappears. It is measured in Kelvin, and rangesfrom 1,800K (very warm, amber) to 8,000K(cool). 6,500K is daylight. There are many coloursof white available. For general use these are: awarm white (2,600 to 2,700 degrees Kelvin), a

medium white (3,000 to 3,500 degrees Kelvin)and a cool white (4,000 degrees Kelvin).

Control gearA package of electrical or electroniccomponents including ballast, power factorcorrection capacitor and starter. High-frequencyelectronic control gear may include othercomponents to allow dimming etc.

CRIColour rendering index has been defined by theCIE (Commission Internationale de lEclairage).The CRI is specified in Ra. Good colour renderingequates to a high CRI (CRI 100 = daylight),poor colour rendering equates to a low CRI.

DiffuserA translucent screen used to shield a lightsource and at the same time soften the lightoutput and distribute it evenly.

Discharge lampA lamp which produces illumination via electricdischarge through a gas, a metal vapour or amixture of gases and vapours.

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Efficacy (luminous efficacy)The ratio of light emitted by a lamp to the powerconsumed by it, that is, lumens per Watt. Whenthe control gear losses are included, it isexpressed as lumens per circuit Watt.

IlluminanceThe amount of light falling on an area, measured inlux. 1 lux is equal to one lumen per square metre.

KelvinA measure of colour temperature for lamps.

Light output ratio (LOR)

The ratio of the total amount of light output of alamp and luminaire to that of just the bare lamp.

LuminaireA light fitting and lamp including all componentsfor fixing and protecting the lamps, as well asconnecting them to the supply.

LumenUnit of luminous flux, used to describe the amountof light produced by a lamp.

LuxAn international unit of measurement ofilluminance intensity of light.

Maintained illuminanceThe illuminance averaged over the referencesurface at the time maintenance has to becarried out (by replacing lamps and/or cleaningluminaires and room surfaces).

RaThe colour rendering performance of a lamp isdescribed by its general colour rendering index(Ra) which defines its ability to show sur facecolours accurately. It is described by a number 100 is considered to be excellent, a value of80 and above is good and appropriate for mostsituations where people are present. Wherecolour identification is important, a value of

90 or above should be used.

Rated average lamp lifeThe number of hours after which half thenumber of lamps in a batch fail under testconditions.

Re-strikeThe time taken for a lamp to illuminate afterbeing switched off and then on again.

Start-upThe time taken for a lamp to illuminate afterbeing switched on from cold.

Lighting for taskThe lighting provided for specific tasks within alighting design. For example, task lighting designwill depend on the particular tasks undertakenand the building lighting design.

Universal operating positionRefers to a lamp that can be oriented in any waywithout affecting light quality.

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CTV049The Carbon Trust is a not-for-profit company with the mission to accelerate the move to a low carbon economy.We provide specialist support to business and the public sector to help cut carbon emissions save energy and
http://www.carbontrust.co.uk/http://www.carbontrust.co.uk/http://www.carbontrust.co.uk/carboncalculatorhttp://www.carbontrust.co.uk/carboncalculatorhttp://www.carbontrust.co.uk/publicationshttp://www.carbontrust.co.uk/publicationshttp://www.carbontrust.co.uk/eventshttp://www.carbontrust.co.uk/eventshttp://www.carbontrust.co.uk/onlinetraininghttp://www.carbontrust.co.uk/casestudieshttp://www.carbontrust.co.uk/casestudieshttp://www.energyefficiencyfinancing.co.uk/http://www.energyefficiencyfinancing.co.uk/http://www.carbontrust.co.uk/casestudieshttp://www.carbontrust.co.uk/onlinetraininghttp://www.carbontrust.co.uk/eventshttp://www.carbontrust.co.uk/publicationshttp://www.carbontrust.co.uk/carboncalculatorhttp://www.carbontrust.co.uk/


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The Carbon Trust receives funding from Government including the Department of Energy and Climate Change, the Departmentfor Transport, the Scottish Government, the Welsh Assembly Government and Invest Northern Ireland.

Whilst reasonable steps have been taken to ensure that the information contained within this publication is correct, the authors,the Carbon Trust, its agents, contractors and sub-contractors give no warranty and make no representation as to its accuracyand accept no liability for any errors or omissions. Any trademarks, service marks or logos used in this publication, and copyrightin it, are the property of the Carbon Trust. Nothing in this publication shall be construed as granting any licence or right to useor reproduce any of the trademarks, service marks, logos, copyright or any proprietary information in any way without theCarbon Trusts prior written permission. The Carbon Trust enforces infringements of its intellectual property rights to the fullextent permitted by law.

The Carbon Trust is a company limited by guarantee and registered in England and Wales under Company number 4190 230with its Registered Office at: 6th Floor, 5 New Street Square, London EC4A 3BF.

Published in the UK: December 2011.

The Carbon Trust 2011. All rights reserved.

We provide specialist support to business and the public sector to help cut carbon emissions, save energy andcommercialise low carbon technologies. By stimulating low carbon action we contribute to key UK goals of lowercarbon emissions, the development of low carbon businesses, increased energy security and associated jobs.

We help to cut carbon emissions now by: providing specialist advice and finance to help organisations cut carbon setting standards for carbon reduction.

We reduce potential future carbon emissions by: opening markets for low carbon technologies leading industry collaborations to commercialise technologies investing in early-stage low carbon companies.

www.carbontrust.co.uk

0800 085 2005
http://www.carbontrust.co.uk/http://www.carbontrust.co.uk/

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