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					                                                                                                                   MAY 2004 SERIES 2 • MODULE 02




      The Continuing Professional Development programme SERIES
                                                                 CURRENT THINKING ON...


                                                                 ARTIFICIAL LIGHTING
                                                                 BY TREVOR FLOYD, TENBY CONSULTING GROUP

                                                                 Introduction                                      fittings which collectively will require about
                                                                 How many of us take artificial lighting for       1kW of electricity an hour to remain lit. This
                                                                 granted? Most of us is the answer. We all         kWh will cost between 2.5 and 7.5p per unit
                                                                 walk out of lit rooms and spaces and forget       depending on your supplier. Now consider
                                                                 to turn the lights off. Unfortunately, there is   how many hours a day, week and year that
                                                                 no sense of ownership of this resource and        room is lit when no one is using it. Even just
                                                                 that is where users can pay a high price.         saving 1 hour per working day will reduce
                                                                 Evaluation of many working locations              energy costs by £60 - £180 annually - a
                                                                 indicates that the amount of electricity          very worthwhile initiative. Also don’t forget
                                                                 consumed in lighting the workplace could          the Climate Change Levy because if you are
                                                                 be up to 1/3rd of the total electricity bill,     paying that as well then the saving
                                                                 even when plant and machinery are also            increases by £10 - £30 annually if it hasn’t
                                                                 employed. In offices, lighting is the single      already been included in the unit price.
                                                                 biggest cost within the electricity bill
                                                                                                                   Automation
Lighting can make up as much as a third of                       Basic costing                                     Unfortunately, human beings are fallible
the total electricity bill of some workplaces                    Why should lighting cost so much? A simple        and we seem reluctant to take control of
                                                                 counting exercise will soon demonstrate           something as simple as lighting. It may not
                                                                 the impact on the bill. It is a straightforward   be our fault as we cannot find the switch, or
        Energy
WELCOME Industryin Buildings and       and the Energy
Institute are delighted to have teamed up to bring you this
                                                                 exercise to note down all of the different
                                                                 types of lights installed at your location and
                                                                                                                   someone prefers artificial light, or we are
                                                                                                                   not the last one out. Whatever the reason
Continuing Professional Development initiative aimed at          to ascertain their rating (possibly with the      for not turning them off, technology can
energy managers.                                                 help of the electrician or by going into the      come to the rescue in the form of
    This is the second module in this series and focuses on      stores to check the ratings of the spare          automatic lighting controls. These can be
lighting. It is accompanied by a set of multiple-choice          lamps). Then multiply these two figures by        as simple or as complex as we wish to make
questions. To qualify for a CPD certificate readers must         the number of hours that they each run per        them. By now, most of us will have
submit at least eight of the ten sets of questions from the      day and thereby per annum. Dividing by            experienced Passive Infra Red (PIR) lighting
modules to be published in the next ten issues to EiBI for       1,000, if the ratings are in watts, will give a   controllers in spaces such as public toilets.
the Energy Institute to mark. Anyone achieving at least          value of kilowatt hours consumed. Then            These, like burglar alarm movement
eight out of ten correct answers on eight separate articles
                                                                 look at your electricity bill to see how much     sensors, will detect the warmth or
qualifies for an Energy Institute CPD certificate. This can be
                                                                 you pay per kilowatt hour - this will give you    movement of a warm body and react by
obtained, on successful completion of the course, for a fee
of £15 (for members) or £25 (for non-members).                   a guide to the annual cost for the electricity    turning on the lights (and sometimes the
    The articles, each written by a qualified member of the      consumed. You will be surprised by the            extract fan). If the detector has blind spots
Energy Institute, will appeal to those new to energy             amount, especially when you realise that          a number of suppliers can provide sensors
management and those with more experience of the                 even that amount may be underestimated            that react to other stimuli such as sound.
subject. The following topics will be coming up: space           because any fluorescent or discharge lamp         Others will not operate unless it is dark
heating; boilers and burners; drives and controls; air           will actually consume up to 125 per cent of       (similar to the security lights that many of
conditioning; monitoring and targeting; training; utility        the value shown on the lamp or tube as            us use outside our homes to scare away
purchasing; and building management systems. The March           energy is consumed in the ballast or the          unwanted visitors).
issue included the first module on the subject of metering.      control gear behind the lamp.                        Such devices, depending on their
    If you miss any of the modules during the year let us           Once this exercise has been carried out it     sophistication, cost less than £50 per unit
know (mark.thrower@btinternet.com) and we will send the          is easy to work backwards to calculate the        to purchase (but allow for the cost of
missing modules to you by e-mail in ‘pdf’ format.                hourly running costs for one room or              installation which may be as much again).
    We hope you enjoy the series and hope they provide
                                                                 location. In a conference, meeting, or board      So, for the board room mentioned earlier,
useful information. Let us know what you think of them and
                                                                 room there may be a collection of eight           they could pay for themselves in a year or
what subjects you would like to see covered in the future.
MARK THROWER, MANAGING EDITOR                                    recessed square 600 x 600mm light                 less as long as one hour of artificial lighting



               Produced in association with
                                                                                                 ARTIFICIAL LIGHTING       FUNDAMENTAL SERIES MAY 2004         21
is saved per working day in the space            Venetian or vertical blinds so that we have
controlled. Most security and street lights      to use more electric light. If heat is the
are now controlled solely by photocells          problem, there are a number of solar
which detect when daylight is fading or          reflective films that will reject 75 per cent
returning to switch them on and off. Timers      of the thermal energy and glare while still
are fallible as they may not respond to          allowing in much of the light. For offices the
British Summer Time changes or some              glare will only appear for a short part of the
other artificial alteration such as a power      day depending on the time of day and year,
interruption.                                    so blinds do not have to be continuously
   Some types of lamp control gear (see          drawn to create constantly artificially lit
later) have the benefit of being able to be      ‘work cells’. However, a combination of
dimmed. The fitting of a photocell with          glare and solar gain often leads to “blinds
variable output to these circuits will           down - lights on” syndrome. Note that
actually increase or decrease the supply,        internal blinds do not stop solar gains
and thereby the energy consumed, at the          entering the space!
luminaire. This will provide a constant             It has been recognised that daylight
lighting level whatever the circumstances,       working is far healthier than artificially lit
as long as someone is in the lit space.          environments and there are now a number
   Finally, there are sophisticated systems      of products on the market that facilitate
that can be programmed to operate a              getting daylight to the point of use. Typical
whole building lighting installation. Out of     of these are light pipes that use polished,
operational hours certain fittings will be       highly reflective tubes to channel light from
controlled to provide sufficient light for       a roof to spaces underneath. In a typical
security walk-throughs or cleaning staff         case study, a hospital replaced all of its
activity. At a pre-set time the system will      corridor fluorescent fittings with light pipes
make power available to all the fittings and     fitted with a small internal compact
they will light, but only if someone is          fluorescent lamp. During the daylight hours
present and there is insufficient daylight. At   no electricity is consumed in this 1/4 mile
all times the zones are being monitored and      corridor unless a severe storm passes. Only
controlled. Some case studies have               then and at night do the CFLs come to life.
indicated that lighting costs have been             However, daylight can only be used in
reduced by up to 75 per cent in this way so      relatively shallow buildings, and is normally
saving 25 per cent of your whole electricity     not significant at a distance from the
                                                                                                     There are now many products
bill without living in darkness (75 per cent     windows of more than 2.5 times the
                                                                                                     available that facilitate getting
off 1/3rd of your electricity bill)!             window height - of course light pipes can be        daylight to where it is needed
                                                 used in deep buildings.
Day lighting
All too often natural light is prevented from    Lighting Levels                                  Lighting at Work that it regards as the
entering our buildings because it brings         There are no laws to dictate the actual level    minimum necessary for safety. These levels
with itself heat and glare. Roof skylights are   of light required for any particular             ensure that tasks can be carried out
allowed to get dirty or painted over and         application. However, the Health and             efficiently. Alongside this bodies such as the
office windows are blanked out with              Safety Executive publishes levels in             Society of Light and Lighting (part of the
                                                                                                  Chartered Institution of Building Services
                                                                                                  Engineers) publish recommendations on
   Lighting relationship guide – watts per lumen                                                  lighting for a wide range of interior and
                                                                                                  exterior applications. Such
         Tungsten                                                                                 recommendations carry no legal status but
                                                                                                  can be regarded as best current practice.
 Mini fluorescent                                                                                    The situation has changed however in
                                                                                                  the past couple of years with publication
      Fluorescent                                                                                 of the first of a series of European
        High Freq.                                                                                Standards on lighting. Such standards are
      fluorescent                                                                                 not normally mandatory, but where a
                                                                                                  project comes within the scope of the
          Mercury
                                                                                                  public procurement directives there is a
      Metal halide                                                                                requirement that European Standards be
                                                                                                  followed where they exist. To allow for
               SON                                                                                this situation, the Society of Light and
                                                                                                  Lighting has aligned its recommendations
               SOX
                                                                                                  with this standard. As well as
                                                                                                  recommendations covering the actual
                                                                                                  task, the standard lays down levels for




ARTIFICIAL LIGHTING
22   FUNDAMENTAL SERIES MAY 2004
                                                 Table 1
                                                  Type                           Lumens/Watt          Colour Temp.     Colour          Life Hours
                                                                                                     degrees Kelvin Rendering (Ra)
                                                  Tungsten                            12                2600             100              1000
                                                  Tungsten Halogen                    18                3000             100          2000-3000
                                                  Compact Fluorescent                 70              2700-4000           85            8000+
                                                  38mm T12 Fluorescent                67                3500              59             7000+
                                                  26mm T8 White Tube (s/g)            77                3500              58            8000+
                                                  26mm T8 White Tube (hf/g)           88                3500              58            8000+
                                                  26mm T8 Full spectrum               64                5000              95             17500
                                                  26mm T8 H/F Triphosphor            100              2700-6000          80+         12000-18000
                                                  16mm T5 H/F Triphosphor           90-106            2700-6500          80+            16000+
                                                  Metal Halide                      60-80             3000-4000         65-85         6000-8000
                                                  Mercury                             45              3900-4300         40-49           12000+
                                                  Mercury Plug in                     45              3300-3600         50-70         8000-10000
                                                  Low Pressure Sodium / E            138                 1800              0             6000
                                                  High Pressure Sodium                82                2200              60            12000+
                                                  H P Sodium Plug in                  85                2000              23            12000+
                                                  White Sodium                        40                2500             80             8000+
                                                  Inductive                           70              3000-4000           85         10000-60000

                                                 by the fact that they cannot be compared                common lamp employed in homes, offices
                                                 on the light output alone. The basic                    and factories is the universal tubular
                                                 parameters, apart from the application,                 fluorescent lamp. Even here there are
                                                 are lumens/watt or how much light is                    many choices. Currently there are three
                                                 emitted for every watt of electricity                   diameters of lamp available in 38, 26 and
                                                 supplied, the colour temperature, the                   16mm in various lengths plus a wide range
                                                 colour rendition capabilities, the life and             of compact units.
                                                 how efficiently the luminaire makes use of                 Compact fluorescent lamps (CFLs) were
                                                 the light from the lamp.                                designed to directly replace the standard
                                                    Table 1 indicates that an incandescent               incandescent lamp but initially struggled
                                                 lamp has a low efficiency and life but                  for acceptance because of their price and
                                                 provides a pure white light so colour                   size. Now they are manufactured in a wide
                                                 rendition is excellent; it is also cheap as it is       range of styles such that they provide as
                                                 the most common light bulb available and                much light within an envelope the same
                                                 comes in a wide range of sizes and light                size as the original tungsten. They may still
                                                 level output. A low-pressure sodium                     cost four or more times as much as a
                                                 discharge light is one of the most efficient            tungsten lamp but they have a life at least
                                                 emitters available and has a mid range plus             ten times as long and also use about 20 per
corridors and other areas of the building.       life but its colour rendition capabilities are          cent of the energy for the same light
   There is one specific case where there        non-existent since it emits only one colour             output. A 100W incandescent lamp can be
are legal requirements, thought they are         of light. They are used for streetlights,               replaced with a 22W CFL with no noticeable
not spelled out. This is the 1992 Health and     security, and sometimes warehouses.                     effect apart from possibly a split-second
Safety (Display Screen Equipment)                However, as all drivers know, car colours               flicker as it starts. The major advantage of
Regulations. These require that lighting for     become either light or dark under their                 the more expensive lamp is that it will save
work stations where DSE is used should be        light. They are not suitable for use in any             the user approx. £50 in electricity for the
suitable for the purpose. An HSE guidance        continuously occupied interior.                         one fitting over its life (which is usually
document indicates what the HSE sees as             One of the issues with luminaires is how             guaranteed by the manufacturer). The
good practice.                                   often they need maintenance or lamp                     purchaser should always be aware that, as
   Common sense would indicate that less         replacement. If the fitting is at a height, or          with all lamps, there are cheap foreign
light is required in a corridor than at a work   is awkward to access, the maintenance                   imports which do not offer or meet the
desk. Yet many buildings are fitted with         staff will have to acquire access                       guaranteed life. It should be noted that
identical fittings in both areas. Guidelines     equipment plus access time when their                   many different types of compact lamp are
indicate that corridors actually need about      equipment does not interfere with                       now available designed specifically for
1/3 of the light required to perform             production. Long life could therefore be a              different applications and fittings.
paperwork in the office. This means three        premium aspect of that purchasing                          Standard linear lamps are designated
times as much energy is being consumed as        decision. In this case, the purchaser may               T12, T8 and T5 which is based on an old
is necessary and therefore considerable          be tempted to go for expensive induction                specification of the imperial units of eighths
continuous waste will take place.                lamps as they offer output for over                     of an inch. So a T12 is twelve eighths of 1.5
                                                 60,000 hrs or seven years of continuous                 inches diameter (38mm). The so-called
Luminaires                                       use with good colour rendition.                         ‘slimline’ is therefore eight eighths or one
The purchasing of luminaires is an art in                                                                inch (26mm) and the latest T5 is five
itself with the wide and diverse range now       Fluorescent lights                                      eighths (16mm). The older T12 tubes can be
available. The problem is only compounded        Over the past few decades the most                      replaced with the T8 type which offer an




                                                                                   ARTIFICIAL LIGHTING           FUNDAMENTAL SERIES MAY 2004        23
FUNDAMENTAL
        SERIES
automatic 8 per cent+ saving in energy as                                                                           removes the problem of stroboscopic                                                                              discharge emitter is that unlike ALL others
they are coated with more reactive                                                                                  effect where rotating machinery, lit by                                                                          they cannot be turned on and off as
material. Unfortunately, the even more                                                                              50Hz fluorescent lighting, can synchronise                                                                       required. Again, yellow sodium street lights
efficient T5 tubes cannot be retrofitted                                                                            with the light and appear to be stationary                                                                       are a good demonstrator. When they first
they require specially designed control                                                                             and therefore confusing and dangerous to                                                                         light up they do not give out much light and
gear. As Table1 shows the T5 generally                                                                              machinery operators. Also, working                                                                               may take a number of minutes to warm up.
offers the most light per watt of electricity                                                                       exclusively under 50Hz fluorescent lighting                                                                      This will even happen if they are turned off
as well as offering at least twice the life of                                                                      can cause headaches and eye strain in                                                                            and then immediately back on again. Areas
the T12. Note that T12 38 mm lamps are                                                                              some staff. The high-frequency operation                                                                         exclusively lit by discharge units could
effectively obsolete and should not be used                                                                         removes those two problems.                                                                                      produce a Health and Safety risk as a brief
for new installations except in the 2,400                                                                              An added advantage is that regulated                                                                          interruption in power supply could create a
mm length.                                                                                                          high frequency ballasts are controllable                                                                         blackout at night for several minutes. Some
                                                                                                                    and therefore a variable signal from a                                                                           fluorescent lighting should therefore be
Hi-frequency                                                                                                        photocell can be used to increase and                                                                            provided where there is a risk from
As the fluorescent light still appears to be                                                                        decrease the lighting level. Fluorescent                                                                         machinery or processes which cannot be
the most popular and common fitting there                                                                           lights therefore become dimmable and light                                                                       terminated immediately.
have been other major improvements both                                                                             output can be matched to needs.
in lamp coatings and control gear. All                                                                                                                                                                                               The future
modern lamps are of the tri- or multi-                                                                              Discharge lighting                                                                                               Light emitting diodes have now moved out
phosphor type which offer high efficiency                                                                           Another common form of large space                                                                               of the field of indicator lights and are now
plus good colour rendering. Old-style                                                                               lighting with many applications high-                                                                            appearing as light sources. They can
halophosphate lamps should not be used as                                                                           pressure discharge lighting. In this type the                                                                    already be seen in lighting clusters on the
they are considerably less efficient.                                                                               control gear causes an arc to be generated                                                                       back of cars and in some replacement
However, they are readily available and                                                                             in a glass enclosure. They first appeared as                                                                     traffic lights. They have now become so
cheap so maintenance instructions need to                                                                           mercury lights and then low pressure                                                                             bright that they can be used in torches with
be specific.                                                                                                        sodium. Now high pressure and white                                                                              lenses to produce a beam of light. The
   The main development in control gear is                                                                          sodium emitters, with reasonably high                                                                            lighting industry has high hopes for the
the replacement of the standard wire                                                                                efficiencies, have taken over as they offer                                                                      LEDs future as they can be produced at
wound ballast with an electronic or semi                                                                            reasonable colour rendition with                                                                                 reasonably low cost. Colour rendition is
electronic device which converts the supply                                                                         reasonable life and cost. Of this range the                                                                      improving and as they have an extremely
frequency from 50Hz to between 18,000                                                                               current market leader is the metal halide                                                                        long life they may never have to be
and 28,000Hz. Apart from offering up to a                                                                           type which covers all features at mid level                                                                      replaced in an application until it is
15 per cent improvement in energy                                                                                   and at a good price.                                                                                             refurbished. Best of all, energy
consumption, the high-frequency operation                                                                              The one major disadvantage of any                                                                             consumption level is very low. ■


  MODULE 02 TEST QUESTIONS
  Please mark your answers on the sheet below by placing a cross in the box next to the correct answer. Only mark one box for each question. You may find it helpful to mark the answers in pencil
  first before filling in the final answers in ink. Once you have completed the answer sheet in ink, return it to the address below. Photocopies are acceptable.

     1. What is the possible proportion of your                                                                               4. What does a Photocell detect?                                                                          8. What does CFL stand for?
     electricity bill spent on lighting energy?                                                                               ■ Movement                 ■ Heat                                                                         ■ Cathode Field Limit
     ■ 11 per cent                                                                                                                                                                                                                      ■ Compact Fluorescent Lamp
                                                                                                                              ■ Light                    ■ Electricity
     ■ 22 per cent                                                                                                                                                                                                                      ■ Compact Flood light
     ■ 33 per cent                                                                                                                                                                                                                      ■ Cool Flow lighting
     ■ 44 per cent                                                                                                            5. Which is the most cost effective (and
                                                                                                                              sustainable) light source?                                                                                9. What is the operating range of High Frequency
     2. How much extra does a fluorescent lamp fitting                                                                        ■ Fluorescent               ■ Discharge                                                                   Fluorescent ballasts?
     consume over the indicated tube rating?                                                                                  ■ Tungsten                  ■ Day light                                                                   ■ 10 - 50Hz
     ■ 10 per cent                                                                                                                                                                                                                      ■ 50 - 1,000Hz
     ■ 25 per cent                                                                                                            6. How long could an inductive lamp last in                                                               ■ 1,000 - 18,000Hz
     ■ 50 per cent                                                                                                            continuous use?                                                                                           ■ 18,000 - 28,000Hz
     ■ 100 per cent                                                                                                           ■ 6 months                  ■ 1 year
                                                                                                                              ■ 3 years                   ■ 7 years                                                                     10. What is the primary concern about discharge
     3. What does P I R stand for?                                                                                                                                                                                                      lighting?
     ■ Passive Infra Red                                                                                                      7. Which is the most energy efficient light source?                                                       ■ Colour rendition isn’t good
     ■ Positive Indicator Result                                                                                                                                                                                                        ■ They are very expensive
     ■ Phase Inductive Return                                                                                                 ■ Low pressure Sodium      ■ Tungsten                                                                     ■ They don’t light immediately
     ■ Primary Instant Reaction                                                                                               ■ Fluorescent              ■ Discharge                                                                    ■ They go out by themselves



     Name ....................................................................................................................................................................................... (Mr. Mrs, Ms)                    Completed answers should be mailed to:
     Business Address ..........................................................................................................................................................................................
                                                                                                                                                                                                                                   The Education Department,
     Town ................................................................................................................................................................................................................
                                                                                                                                                                                                                                   Energy in Buildings & Industry,
     ...........................................................................................................................................................................................................................

     Post Code................................................................................................... email address..........................................................................
                                                                                                                                                                                                                                   P. O. Box 825,
     Tel No...............................................................................................................................................................................................................         GUILDFORD, GU4 8WQ

                                                                                                      EDITORIAL Managing Editor: Mark Thrower Tel: 01483 452854
FUNDAMENTAL
        SERIES
                                                                                                      E-mail: mark.thrower@btinternet.com

                                                                                                      PUBLISHER Pinede Publishing, 16-18 Hawkesyard Hall, Armitage Park, Nr. Rugeley, Staffordshire WS15 1PU.
24    FUNDAMENTAL SERIES MAY 2004                                                                     Tel: 01889 577222 Fax: 01889 579177

				
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