lighting_diemnsions

3653_SSLD_lighting_AW 17/10/07 12:09 Page i

Lighting systems in schools

3653_SSLD_lighting_AW 17/10/07 12:09 Page ii

Acknowledgments
We are grateful to the following individuals Linton Ross, Feilden Bradley Clegg Architects
and organisations that have contributed to Peter Clegg, Feilden Bradley Clegg Architects
this document: Paul Hetherington, Alumasc
Richard Parker, AMEC
Bea Etayo, Fulcrum Consulting
Andrew Williams, BRE
Christina Skandali, Fulcrum Consulting
Bill Healy, Build Offsite
Ian Morris, Atkins
Richard Ogden, Build Offsite
Iain Macrae, Thorn Lighting
Mike Entwisle, Buro Happold
Daniel Glynn, CP Electronics
Rita Singh, Construction Products Association
Chris Grabe, EC Harris
Michael Ankers,
Mark Cleverly, EC Harris
Construction Products Association
Joanne Martin, Thorn Lighting
Bea Etayo, Fulcrum Consulting
Peter Blunt, Mtech Group
We are also grateful to the following members Martin Goss, Mtech Group
of the Standard Specifications, Layouts and David Mackness, SCAPE System Build Ltd
Dimensions (SSLD) Forum who have helped Martin Lipson, 4Ps
shape the broad approach to standardisation Mairi Johnson, CABE
in this and other guidance documents in Richard Saxon, CBE
this series: Peter Woolliscroft, OGC
Richard Brindley, RIBA
Mukund Patel, DCSF (SSLD Chair) Vic Ebdon, Devon County Council
Alan Jones, DCSF (SSLD Policy Lead) Don Bryson, D B Consultancy
Ian Morris, Atkins (SSLD Project Manager) Kevin Kendall, Nottinghamshire County Council
Beech Williamson, Partnerships for Schools
Paul Foster, EC Harris
Michal Cohen, Walters and Cohen Architects
Karen Rogers, Walters and Cohen Architects
Christian Held, Penoyre and Prasad Architects
Sunand Prasad, Penoyre and Prasad Architects

3653_SSLD_lighting_AW 17/10/07 12:09 Page 1

Contents
1 Introduction 2 3 Performance specifications
Who this guidance is for 2 and examples 24
How the guidance should be used 2 Space and lighting types 25
Background to Standard Specifications, Performance specifications 27
Layouts and Dimensions (SSLD) 4 TYPE A – General (for most teaching
Aims and scope of this guidance 5 and non-teaching areas) 27
TYPE B – Practical (where more light
2 Key performance requirements 6 is required) 30
Lighting to support teaching and learning 7 TYPE C – Performance (stage lighting and
Health and safety 9 lighting to enhance performing arts) 31
Disability issues 10 TYPE D – Sports (for sports and multi-
Sustainability 10 purpose halls) 32
Energy efficiency 12 TYPE E – Reception/social (for non-teaching
Lamps 13 areas where lighting can be more diverse) 33
Luminaires 16 Type F – Circulation 35
Controls 19 Type G – Service areas (non-teaching
Maintenance 20 spaces such as storage areas and toilets) 36
Emergency lighting 21
Cost comment 22 4 References and Glossary of terms 38

Lighting in schools 1


Introduction

This guidance is one of a series of Who this guidance is for
Standard Specifications, Layouts and • Teachers and governors acting as clients
for school capital projects
Dimensions (SSLD) notes produced to
inform the Building Schools for the • Local authority officers responsible for
procuring school capital projects
Future (BSF) programme.
• Diocesan building officers
• Local authority and private sector school
designers and specifiers
• Manufacturers and suppliers
• Contractors

How the guidance should be used
This guidance sets out the standards of
performance for lighting systems in the
Building Schools for the Future (BSF)
programme and shows through some
examples how they might be delivered. It is
one of a number of publications on various
building elements within the SSLD series.
The aim is to disseminate best practice and
avoid ‘reinventing the wheel’ every time a
school building is designed, so that consistently
high quality environments can be delivered,
offering best whole-life value for money.

2 Standard specifications, layouts and dimensions


School building clients, their professional
advisers, contractors and their supply chains
should use this guidance to inform their
decisions on lighting systems at the early
stages of a project’s development – whether
new build, extension or refurbishment – at
RIBA Stages A-F.

To help encourage the take up of these
performance specifications, this guidance
will become the standard in BSF programme
documentation and the Government will
expect it to be adopted in the majority of
situations where it is reasonable and
appropriate to do so.

While we would expect projects to comply with
the standards, other solutions – possibly based
on new products or technologies, or reflecting
local factors – may equally comply with the
performance specification and could be used.
We do not want to stifle innovation by being
too prescriptive.

It will be for users to exercise their own skill
and expertise in deciding whether a standard
or example shown in this document is
reasonable and appropriate for their own
circumstances. This guidance does not affect
obligations and liabilities under the law
relating to construction and building.



Though principally aimed at secondary school Background to Standard Specifications,
building projects delivered through the BSF Layouts and Dimensions (SSLD)
programme, the specifications and examples The BSF programme offers a unique
may also apply to other educational buildings. opportunity over the next 10-15 years
We will keep this guidance under review and to transform our secondary schools, providing
update it as necessary to reflect the innovative learning environments that will
development of new products, processes and inspire pupils to achieve more. High
regulations. There is a web-based version at quality, modern school buildings will help
www.teachernet.gov.uk/schoolbuildings to raise standards and play a crucial part in
the Government’s programme of
educational reform.

With the huge increases in funding associated
with this programme, there is considerable
scope for using standardised specifications,
layouts and dimensions to speed up design
and construction, reduce whole-life costs and
deliver consistently high quality and better
value school buildings. Standardisation will
support the use of more off-site fabrication and
modern methods of construction, which should
help to improve health and safety performance,
reduce waste and deliver more sustainable
solutions. For the supply industry, being
involved in standardisation will help to
demonstrate market leadership – and help
firms reduce risk and increase sales, profitability,
and market size.

The examples in this document and
the others in the SSLD series have been
developed based on extensive consultation
under the auspices of the SSLD Forum. Set up
by the Department for Children Schools and
Families (DCSF), this forum represents key
stakeholders in the building design, research,
contracting, and supply industry
communities, as well as local authority
construction client bodies.



Aims and scope of this guidance
This document provides standard
performance specifications and some
examples to help with the choice of
lighting systems in BSF secondary schools.

Specifically it:

• sets out minimum standards of performance
and quality expected by the DCSF
• provides design guidance for project
designers formulating technical specifications
• standardises lighting requirement types so
that efficiencies and economies of scale can
be generated within the supply chain
• enables caretakers and facilities managers This guide has been produced to inform rather
to manage lighting systems. than replace detailed project specifications.
It is structured as follows: Descriptions are given in generic terms and
are not intended to promote the products
Section 2 of specific manufacturers. Contractors and
The generic performance requirements for specifiers should consult with relevant
lighting systems in secondary schools. manufacturers to establish which products
are appropriate and compliant.
Section 3
A summary of the minimum performance When client bodies are compiling output
requirements of lighting systems for each of specifications, they may decide simply to state
the school areas as defined in Building Bulletin a ‘lighting type’ (A to G) for a particular space
98, together with some examples. (see Section 3 for details), or alternatively
develop with their professional advisors
Section 4
a particular specification that meets
References to relevant European, British
their requirements.
Standards, DCSF and other design guidance.

A glossary of terms.



Key performance requirements

The following key performance This document is not a lighting design guide.
requirements set the minimum Its purpose is to make clear the client
requirements, the minimum standards to be
standards that DCSF would expect to reached or exceeded and what is expected to
be adopted in BSF schools wherever provide the best lighting environments for BSF
it is reasonable and appropriate. and other school projects. More detailed
Section 3 defines the specific lighting information is available in DCSF Building Bulletin
90 Lighting Design for Schools1 and further
requirements for each space and references listed in Section 4. While technical
provides some examples that terms are explained in the Glossary in Section 4,
address them. it may be helpful to explain some of the terms
here to assist understanding of the subject:

• Illuminance
Average light level required which makes
it easy and comfortable to carry out school
activities. This is the minimum illuminance
that should be provided on the activity area.
• Uniformity ratio
Excessive variation of illuminance across
the area where activities take place
can be distracting and reduce visual
performance. Uniformity ratio establishes
minimum value in order to avoid excessive
contrast and distraction.

1 www.teachernet.gov.uk/lighting



• Limiting glare rating
For electrical lighting installations, in order to
avoid bright sources in the line of view, the
limiting glare rating indicates its maximum
value permitted.
• Colour rendering
Colour plays an important role in learning; a
good colour rendering performance enables
accurate colour judgements to be made.
This value indicates the minimum colour
rendering value of the lamps to be used.

Lighting to support teaching and learning
The primary objective of good lighting design
in any type of building is to provide a well
illuminated and safe working environment,
which provides occupants with a feeling of
well-being and allows them to perform their
visual tasks.

The key performance requirements below
refer to lighting over the activity areas but the
electric lighting design should also enhance
the space so that it appears attractive and
interesting. Walls and ceilings should be
illuminated to contribute to these impressions.
Spaces that have areas of light and shade are
generally liked and interesting but it is
important that this variation is not too great.
The colour appearance of the electric light
needs to be considered because different lamp
types produce different degrees of ‘warmth’
or ’coolness’.



Modern learning and teaching is more
personalised and diverse, resulting in
pupils learning in a variety of spaces and in
various ways. A dining area, for example, may
be used for group discussion or individual
reading; a circulation area, such as part of an
atrium, could be used for informal tutoring or
project work; and laptops could be used
everywhere. It is important to find out in the
early stages of briefing and design how spaces
will be used by the school so that lighting
flexibility is designed in.

In most types of buildings, users prefer rooms to
NB To ensure that secondary schools get the have a daylit appearance during daytime hours.
best possible learning environments, In schools, natural lighting during daylight
attractive and efficient for all the people who hours should always be the main light source
use it, it is essential to appoint an experienced for reasons of quality of light and sustainability.
lighting engineer and installation contractor. Electric lighting and natural lighting should be
complementary. Electric lighting will take over
during the hours of darkness and should
supplement natural lighting when it fades.

This guide covers electric lighting together
with controls that encourage the use of electric
lighting only when it is required. To make sure
that running costs and maintenance are
reduced to a minimum, light sources, luminaires
and lighting controls need to be highly efficient,
with a long life. Advice on the specification of
energy efficient light sources and controls is
provided here, together with information on
how to reduce unnecessary variation in lamp
and luminaire types.

Pupils like spaces that are interesting and
unique. They enjoy learning in them even
though lighting conditions may not be ideal.
There is a place for imaginative lighting
environments in schools and this publication
aims to encourage creativity, not create
blandness or uniformity.



Health and safety This problem is controlled by assessing the
Learning and teaching rely upon good lighting. lighting installation in terms of its glare rating
Although poor lighting is easily identified in use, and ensuring that it does not exceed the
it is often overlooked at the design stage. recommended maximum.
Our eyesight is resilient, so we may be unaware Glare can be minimised by:
of the problems caused by poor lighting in our
schools. Yet it can result in slower reading, poor • the correct choice, orientation and positioning
posture, diminished concentration and long- of the room furniture
term weakened vision. • the use of internal or external blinds, which
Lighting in schools is required not only can reduce problems caused by excessive
for general safety but also for visual tasks. sunlight or daylight
The two main issues to guard against are glare • the use of louvres on fluorescent luminaires
and flicker. and/or the use of indirect lighting solutions,
which will help reduce direct vision of
Glare the light source and therefore the instance
Glare is a common problem in the classroom. of glare
It occurs when a bright image (which is not the
• correct choice of computer screen with
object one is trying to see) is seen either directly
anti-glare filters if necessary, together
or by reflected light. This can cause significant
with orientation to avoid sunlight and
difficulty with visual tasks.
daylight reflection
Although pupils try to compensate for glare by • careful design of the illuminance of the
turning their heads or squinting, glare causes whiteboard relative both to sunlight and
eyestrain and headaches and can sometimes be daylight glare and glare from luminaires.
disabling. It can also cause loss of concentration
and reduced productivity. Flicker
Flicker can cause discomfort or annoyance to
Glare can be divided into two types:
some people. It can also produce stroboscopic
• Discomfort glare is not necessarily effects with moving objects, which can be
detrimental to vision but it produces dangerous. For example, rotating machinery
feelings of visual discomfort. in a workshop can appear to be stationary.
Epilepsy can be triggered by low frequency
• Disability glare occurs when a bright light
flashes of light, which can occur with some
source is close to the line of vision and
compact fluorescent lamps at ignition, or with
makes the task more difficult to see.
discharge lamps towards the end of their life.
Problems relating to balance, and some brain
disorders, can also be exacerbated. All these
can be avoided by using high frequency
control gear.



Disability issues • Careful use of colour can help pupils
Good quality lighting is important to help pupils recognise and identify objects. For instance,
learn, especially those with special educational using a darker colour for a door frame
needs (SEN) and/or any disability. Natural (contrasting with door leaf and wall) will
lighting with additional artificial light should help in locating the door. A handle that
be used where necessary, avoiding glare and clearly contrasts with the surface of the
revealing good visual contrast and colour door and is non-reflective will also make it
rendering. Light levels should be adequate easier to distinguish.
on the working plane and for people to clearly • Students with visual impairment often require
see the teacher’s face, the whiteboard and higher than normal levels of illuminance. It is
computers without creating reflections, not necessary to install this as a feature of the
shadows and harsh contrasts. For an even primary lighting system but provision should
better effect, light sources should not be visible, be available for supplementary task lighting.
flicker should be avoided and uplighters should
be used. There is more detailed information in Building
Bulletin BB 772 and Building Bulletin 90.
Hearing impaired people need to be able to see
lip movements clearly, so the correct lighting Sustainability
level and direction are crucial. For example, if The Sustainable Development Commission
light is directed too much in a downward estimates that schools contribute 2% of the
direction, it will produce harsh shadows, UK’s overall carbon emissions, with around half
which will make lip reading difficult. of this arising from the use of electricity and
fossil fuels within school buildings. It is
The design of specialist accommodation for important that we take action to reduce this.
pupils with SEN and/or any disability is beyond The Government has allocated an additional
the scope of this document and specialist investment of £110 million over the next three
advice should be sought. However, there are years to test the aim of reducing carbon
relevant design issues that should be emissions by 60% in new schools built in
considered for all schools: the BSF programme.
• The colour rendering of the light source To meet this aim it will be necessary to use
and the extent of contrast are particularly the most energy-efficient lighting and to use
important. Some visual impairments involve a lighting controls wherever there is a whole-life
degree of colour blindness and it is important cost justification for doing so. Designers must
that contrast of tone as well as colour should consider the specification of lamps, luminaires,
be produced on the objects illuminated. control systems, and illuminance levels in
conjunction with optimum daylighting design
to deliver significant energy savings over
current practice.

2 www.teachernet.gov.uk/management/resourcesfinanceandbuilding/schoolbuildings/designguidance/SENanddisabilities



Artificial lighting currently accounts for the b) For spaces not included above, “it may
highest proportion of all energy costs in be appropriate to provide luminaires for
schools, at around 28%. For this reason, which photometric data is not available or
the lighting installation offers the greatest luminaires that are lower powered and use
potential for saving energy by applying less efficient lamps. For such spaces, the
good management, design, specification requirements would be met if the installed
and controls. The use of automatic lighting lighting has an average initial (100 hour)
controls can save as much as 30 to 40% of lamp plus control gear efficacy of not less
electricity consumption when compared to than 50 lamp-lumens/circuit watt5.”
manual switching3.
c) For display purposes, “reasonable provision
Most electricity is generated by burning fossil would be to demonstrate that the installed
fuels, which cause carbon dioxide emissions, display lighting has an average initial
contributing to climate change. Schools must (100 hour) efficacy of not less than 15
now comply with Part L of the Building lamp-lumens per circuit-watt6. In calculating
Regulations and will need to use carbon this efficacy, the power consumed by any
calculations as prescribed in the approved transformers or control gear should be taken
document. Part L2 (2006) states: into account.”

a) For classrooms, seminar rooms, conference Building Bulletin 87, 2nd Edition Version 1
rooms and office areas, “reasonable provision (May 2003) Guidelines for Environmental
would be to provide lighting with an average Design in Schools7, states that for school
initial efficacy of not less than 45 luminaire buildings, “A minimum of 65 lamp-
lumens/circuit watt4 as averaged over lumens/circuit watt8 should be adopted.”
the whole area of these space types in For normal types of luminaire this is slightly
the building.” in excess of Building Regulation Standards
but should be attained wherever possible.

3 ‘Academy examination’ BSRIA Delta t, June 2007
4 The average luminaire-lumens/circuit-watt is calculated by the lumen output of the luminaire summed for all luminaires in the
relevant areas of the building, divided by the total wattage of all the luminaires.
5,6,8 Lamp-lumens are the initial lumens of the bare lamp on measurements taken after 100 hour usage of the lamp. The efficacy of the
bare lamp (lamp-lumens/circuit-watt) is calculated by dividing the lumen output by the wattage of the lamp.
7 This edition replaces Building Bulletin 87 (1997) as referenced in building regulations Approved Document Part L2 2002.



Energy efficiency New school design
The energy efficiency of artificial lighting New build schools should use all four of these
depends on: approaches but the optimisation of daylight
should always be considered as one of the most
• The penetration of natural lighting indoors – cost-effective options. Staff and pupils should
if there is good daylight distribution in the always take advantage of available daylight.
classroom and good daylight levels, artificial Through much of the year the levels of daylight
lighting may not be required should be sufficient for electric lighting to be
• The luminaire efficiency and its electrical switched off in parts of the school. Most people
components, lamps and control gear prefer to work in a daylit space, provided that
• The successful specification of the lighting solar glare and overheating are minimised.
controls, eg, their usability and response to There are a number of daylight prediction
changing conditions techniques available to designers, ranging
• The operation, cleaning and maintenance from rules of thumb, manual calculations and
regime. graphical analysis, to physical model studies
and computer simulation. There is more
These issues are considered in the following detailed information on natural lighting in
sections of this guidance. Building Bulletin 879, BB 90 Lighting Design
for Schools10 and CIBSE Lighting Guide LG10
Daylighting and Window Design.

Existing school buildings
Existing buildings may be more restricted in
their options for available levels of daylighting.
Existing luminaires should be replaced with
low-energy fittings and signage used to
encourage teachers and pupils to switch
lighting off when it is not needed.

NB Improved lighting controls that can
respond to daylight levels can be expected to
cost more than standard lighting controls that
do not. Further details are included in the cost
comment on page 22.

9 www.teachernet.gov.uk/energy
10 www.teachernet.gov.uk/lighting



Lamps Currently the most energy efficient lamps are:
The purpose of a lamp is to convert electrical • Compact fluorescent
power (watts) into visible light (lumens).
The efficacy of the lamp is measured in lumens • Linear fluorescent
of light per watt of electricity (excluding any • High intensity discharge (metal halide or
local losses in lamp control gear). The energy high pressure sodium).
(watts) largely ends up as heat; highly inefficient The table below shows that the common
lamps with excessive lighting will cause the incandescent lamps have low efficacy.
building to overheat. They should not be used except in some
exceptional circumstances for display lighting.
Coloured LEDs are currently used in some
lamps and used for display/accent lighting.

Table 1

Lamp group Type of lamp Efficacy (lumens/lamp watt)

Incandescent Tungsten filament – common 8-12
GLS (general lighting source)

Tungsten halogen 12-24

Linear fluorescents Triphosphor T5, 16mm 88-104

Triphosphor T8, 26mm 88-100

Compact fluorescent 50-85

High intensity discharge High pressure sodium 65-140

Metal halide 70-100



Compact fluorescent The characteristics that influence lamp
Compact fluorescent lamps are now the selection are:
most usual replacement for the common
• Efficacy, lumens of light per watt of electricity
incandescent lamps. Compact fluorescents can
have integral or separate control gear. Lamps • Colour perception of the lamp – does the
with integral gear are a direct replacement for light appear warm or cool?
standard incandescent lamps. • Colour rendering accuracy – does the lamp
show true colours?
Linear fluorescent
Triphosphor T5 and T8 linear fluorescents are • Lamp life
efficient in many situations due to their high • Dimming capabilities
efficacy. The light output is higher than that for
• Instantaneous light – does the lamp take
compact fluorescents and they should be used
some time to reach full output?
in areas where illumination requirements are
relatively high. This would be appropriate in • Instantaneous re-strike – does the lamp
general teaching areas, light and heavy practical take some time to switch on when hot?
areas, staff, administration and resource areas.
However, the higher light output demands
greater glare control by the luminaire.

High pressure discharge
High pressure discharge light sources are
suitable for large volume spaces that require
high light output. Although high pressure
sodium light sources present very high efficacy,
the quality is not good enough to distinguish
colours clearly, so metal halide discharge lamps
are preferred because of their good colour
rendering. However, it should be remembered
that fluorescent lighting can be used effectively
in sports halls.



Table 2: Lamp data

Linking with lighting control
Ra/colour temperature
(K)/colour appearance
Control gear required

Dimming possible
Designations and

Colour rendering
Efficacy (lumens/

Lamp life (hours)

Lamp start-up/
lamp re-strike
dimensions

lamp watt)
Lamp type

T5 (Ø16mm)
10000-
88-104
15000
288mm-1449mm
Linear Yes
T8 (Ø26mm)
10000-
88-100 50-98/
Tubular 15000
590mm-1764mm
2700-6000/ 1-3 seconds Yes Yes
fluorescent
warm to cold
T5C (Ø16mm)

5000-
Circular 60-80 Yes
8000

Ø225mm-Ø375mm

External
control 82-98/
Compact gear Yes 2700-4000/
50-85 10000 1-3 seconds Yes Yes
fluorescent Internal No warm to
control intermediate-cold
gear
Various

60-93/
Metal Various 6000-
70-100 Yes 3000-10000/ 3-6 minutes No No
Halide shapes 20000
warm to cold

Various

High 25-80/
Various 9000-
pressure 65-140 Yes 2000-3000/ 3-6 minutes No No
shapes 28500
sodium warm

Various



LOR equals the total light output of the
NB In the future there may be developments
luminaire/total light output of the lamp(s)
in lighting using light emitting diodes (LED).
contained in the luminaire. A luminaire which
These incorporate a high purity
only emits half the lamp light output, LOR =
semiconductor which, when activated
50%, would be seen as very wasteful. In all
electrically, generates light. Currently LEDs
cases, luminaires with LOR over 80% should
are commonly used for signalling and feature
be used.
lighting. They need further development to
give reliable white light, in terms both of Eliminating reflection
quantity and quality of light, before they can Some recent developments in luminaire design
be used for general working lighting were generated by the need to eliminate bright
purposes. White and colour LEDs can be used reflections on computer screens. Although it is
for feature and display purposes but not as important to avoid these unwanted reflections,
the sole light source. Some of the latest the problem may have been over-emphasised
developments use lenses to the top of the and the pendulum swung too far in favour of
LED to direct the light coming out, either downward-only lighting. In the past, the
concentrating it in narrow and long light horizontal surfaces were properly illuminated
beams or wider and shorter light beams. but walls and ceiling illumination were
neglected. Good lighting design in working
areas should highlight the vertical surfaces and
Luminaires
the ceiling as well as the horizontal plane.
The luminaire holds the lamp and directs
light in the required direction. It includes all Another issue is the lighting of traditional chalk
components for fixing, protecting the lamps blackboards or whiteboards used with marker
and connecting them to the electricity supply. pens. A dedicated luminaire needs to be placed
It also provides the optical control which above the board to highlight the area.
ensures that the light is directed to where it is
required as well as shielding it from those areas Interactive whiteboards
where it is not needed. This involves the use of A more significant issue is achieving the
reflectors, refractors and/or diffusers. correct lighting environment where interactive
whiteboards are used. There have been
Although a high efficacy lamp is critical for an problems with poor visibility of boards because
efficient lighting installation, lighting choice of incorrect location, orientation, lighting levels,
should be based on luminaire efficiency. direction and glare. It is important to consult a
The optical elements of the luminaire absorb lighting engineer to develop a design that
light, so not all the light from the lamp will coordinates the daylight, artificial system and
emerge from the luminaire. whiteboard location. However there may be
more than one whiteboard position required
The efficiency of a luminaire is defined by
to allow for flexibility.
its light output ratio (LOR).



The tables below show various ways of mounting luminaires and types of light distribution.

Table 3: Luminaire mounting

Ceiling recessed Pendant, suspended

Ceiling
Wall mounted
semi-recessed

Ceiling
semi-recessed



Table 4: Types of light distribution

Light distribution Examples of luminaires

Direct or downwards Surface Recessed Pendant

Indirect or upwards Pendant Wall mounted

Direct-in direct, up and down Pendant Pendant

Direct-in direct, up and down Semi-recessed

Asymmetric Pendant Recessed

Decorative Wall mounted



Lamp control gear Compact fluorescent lamps can house control
Compact fluorescent, linear fluorescent and gear either integrally to the lamp or separately
metal halide lamps are discharge light sources. but close by. Fluorescent control gear usually
All these discharge lamps need current has a longer life than that of the lamp, so when
stabilising control gear – apparatus to start and the lamp fails, another lamp can be inserted
control the electrical current through them. using the existing control gear. Thus new
Control gear is also referred to as ‘ballast’. compact fluorescent installations should always
use separate control gear. When replacing
High frequency electronic control gear is
lamps in existing lighting installations that use
available for linear and compact fluorescent
incandescent lamps, compact fluorescents with
lamps and some high-pressure discharge
integral high frequency control gear should be
lamps. This type of gear offers flicker-free
used wherever possible. In the case of metal
operation and reduces the control gear energy
halide lamps, the control gear can be relatively
consumption in comparison with early types.
large when wattages of the lamp are high, with
Some manufacturers also claim that the lamp
limitations on its location.
life is increased by high frequency control gear.
High frequency control gear should be used in Controls
all cases. Lighting controls and switching
The light output of most light sources can be Often when lights are switched on first thing
controlled so that it can be reduced, dimmed in the morning, they tend to be left on for the
down, in some cases as low as 1% of its full rest of the day, even if daylight in the room
light output. This can be done by using high is sufficient to carry out the required task.
frequency dimmable control gear. Well-planned lighting controls save energy
in two ways:
Modern control gear usually consumes less
energy than earlier types, which means that the 1. They make good use of available daylight,
overall efficacy of the lamp circuit is improved. thus reducing electric lighting used.
For a fluorescent lamp, the control gear is 2. They ensure that electric lights are switched
defined by a CELMA11 energy class, which off when a space is unoccupied.
should be marked on the control gear casing.
These are classified from A to D, although If the location and lighting of whiteboards
current EU regulations demand that all control allows, the zoning arrangement of the
gear should be either a type A (A1, A2, A3) or B luminares should allow lights to be switched
(B1, B2), where A1 is the most efficient and B2 in rows, parallel to windows, so that lights
the least12. Only these categories should be close to windows can be switched off to take
specified for school use. advantage of available daylight.

11 Federation of National Manufacturers Association for Luminaires and Electrotechnical Components for Luminaires in the
European Union.
12 www.celma.org



There are variuous types of automated lighting • Key or card switches are sometimes used in
controls appropriate for schools: occasionally visited spaces. The key or card
is used to switch the lights on; when it is
Manual – e.g. local switch, wireless control.
removed, the lighting is automatically
Manual switches must be simple, carefully switched off. However, they can cause
considered and conveniently located, usually annoyance if access to the card or key
near the door. is difficult.
Automated – e.g. time switch control,
photoelectric control, occupancy/absence Suitable types of controls for various types
detection and key or card control. of spaces are identified in Section 3.

Automated lighting controls should take into
account the type of space, how it is used and Maintenance
the amount of daylight available. To avoid a Over time, dirt accumulates on windows,
feeling of alienation, it is essential that teachers luminaires and room surfaces. Dirty windows
and pupils appreciate what is automated and encourage unnecessary use of electric lighting,
why. There are various types of automated so they should be properly maintained and
control appropriate for schools: cleaned regularly to maintain good lighting
levels. A dirty diffuser or reflector can cut light
• Time switch control could be used for
output by 20%, so a regular cleaning
switching off the main lighting outside
programme is also essential for reflectors,
opening hours.
diffusers and lamps, taking advantage of
• Photoelectric control involves the lamps holiday periods to minimise disruption.
being switched or dimmed in response to
daylight. Failed fluorescent lamps should be replaced
promptly. A fluorescent lamp with a blackened
• Occupancy detection sensors can switch end indicates that it has passed its economic
lights on automatically when the sensor life, although it will last a long time before there
detects occupancy. The sensor requires a time is any blackening or other visible indication of a
delay, which can vary from 15 seconds to 30 drop in performance. Regular lamp replacement
minutes. The lights remain on during the time on a planned maintenance cycle is important to
delay, after which, if no-one is detected, lights avoid lamps operating at reduced output but
automatically switch off. These can be infrared still using the same amount of electricity.
or microwave technology. Specialist luminaire maintenance and lamp
• Absence detection systems switch lights replacement contractors can offer an efficient
on manually, switching them off again cost effective service, including disposal of used
automatically after a time delay when no-one lamps. See Building Bulletin 76 Maintenance of
is detected in the space. These can be infrared Electrical Services for detailed information on
or microwave technology. cost effective replacement cycles for lighting.



Discharge light sources (high pressure as well as normal lighting. Standard fittings can
sodium and metal halide) seldom fail outright. be modified to integrate an emergency facility.
The failure is preceded by an increased
Emergency lighting in schools should be
tendency to flicker, and they might flash on
provided on:
and off repeatedly. Teachers and caretakers
should watch for these signs. • Escape routes
• Escape stairways
Sometimes the lamp itself – whether
fluorescent or a discharge light source – is not • Corridors without any windows
the problem. Instead, the control gear may be • Areas with dangerous machinery
faulty. A fail-safe circuit that disconnects the
• Areas accessible to the public during
control gear if the lamp fails is required. An old
the evenings.
lamp should always be replaced with a new
lamp of compatible rating and of the same These include halls and other spaces used for
colour. Discharge lamps must be matched to performances. For details on areas that require
suitable control gear. It is better to keep the emergency lighting, please refer to:
right lamps in stock than to rely on a
• The Code of Practice for the emergency
commercial supplier at short notice.
lighting of premises BS 5266
Lamp replacement is made considerably easier • Luminaires for emergency lighting BS
if the number of different lamp types is kept to EN 60598-2-22:1999
a minimum when the installation is designed.
• Emergency escape lighting systems BS
Lamps must be disposed of safely and in
EN 50172
accordance with environmental legislation.
The Waste Electrical and Electronic Equipment • Emergency lighting guide LG12, CIBSE
(WEEE) regulations aim to reduce the amount of • Building Regulations Approved Document B,
such electrical and electronic equipment being Fire Safety
disposed of in landfills by promoting separate
• Building Bulletin 100 Designing and managing
collection, treatment and recycling. It is
against the risk of fire in schools.
important to ensure that lamps are recovered,
recycled and disposed of in compliance with In areas used by the public during the hours of
the WEEE regulations. darkness, the emergency lighting should be of
the maintained type, meaning that the lamps
Emergency lighting
contained in a luminaire will operate from the
Emergency lighting must provide sufficient normal supply or from the emergency supply
illumination in the event of a failure of the at all times. Where part of the premises is
normal electric lighting supply, so that the licensed, additional provision may be required
building can be evacuated quickly and safely. and it will be necessary to seek the advice of
There are considerable benefits in integrating the local authority.
the general and emergency installations. Some There is more detailed information in Building
luminaires can incorporate emergency lighting Bulletin 90 and BS 5266.



Cost comment Figure 1 shows an efficient lighting/luminaire
The lighting costs for a building can be divided layout in a typical classroom. The window
into two parts: arrangement is such that an average daylight
factor of 2% is achieved in the room. The
• Capital cost of equipment, including the lighting layout comprises 12 No. 35W luminaires
cost of installation. The cost of this element with 50% up – 50% down distribution. (Please
will typically be around 3% of the total note that all the detailed information above
construction cost of the building. refers to particular luminaires and that these
• Running costs, including both maintenance will change from one manufacturer to another,
and energy cost. from one luminaire to another.)
It is important that professional advisers take The luminaires are switched in rows away from
due regard of both these factors when the windows and are dimmable so as to be
developing project budgets and carry out either dimmed or switched off during daytime,
appropriate option appraisals in order to depending on daylight availability. There are
secure best whole-life value for money. two daylight sensors (photocells) and one
absence sensor (a microwave detector).
The cost impact of installing a high-efficiency
Lighting is switched on, off and dimmed up
lighting design as described in this specification
and down with retractive switches. A dedicated
– i.e. with daylight linking, absence detection
luminaire could also be placed above the
and central manual switches – is compared in
whiteboard to highlight the area, controlled
the case study below with the cost of current
locally with the facility for dimming.
standard, high frequency, controls.
(For interactive whiteboards, local lighting
should not be necessary.)



Though the initial capital cost is about 20% • the majority of luminaires in teaching areas,
higher than a current high frequency system offices and dining halls are suspended from
of controls, the resultant energy savings of exposed soffits without suspended ceilings.
around 36% will have a payback period of This should generate cost savings, even
10-13 years at current energy prices. What’s allowing for some acoustic treatment to
more, the system should reduce carbon the soffit.
emissions from 448kg to 286kg per classroom
On this basis, the rate of return on the
per year, and the payback period is even
additional investment in a high-efficiency
shorter if the social costs of saving carbon13
system can be justified and supports the
are considered. These benefits assume:
Government’s wider carbon reduction
• the diversity of luminaires is minimised strategies. Furthermore, over time there is
wherever possible. This will help to ensure likely to be scope for efficiencies from the
that contractors obtain good discounts from standardised approach, particularly in large
lighting manufacturers and suppliers for bulk serial programmes like BSF, which will help
orders. It will also simplify maintenance and to offset higher initial costs.
arrangements for holding stocks of spares

Figure 1: Plan view of classroom with luminaires perpendicular to the window, complete
with switching arrangement

13 www.defra.gov.uk/environment/climatechange/research/carboncost/index.html



Performance specifications
and examples
This section provides performance The types are:
specifications and examples for seven Type A General (for most teaching and
types of lighting in schools. non-teaching areas)
Type B Practical (where more light
is required)
Type C Performance (stage lighting
and lighting to enhance
performing arts)

Type D Sports (for sports and multi-
purpose halls)
Type E Reception/social (for non-teaching
areas where lighting can be more
diverse)

Type F Circulation

Type G Service areas (non-teaching
spaces such as storage areas
and toilets)



Space and lighting types
Table 5 below shows the majority of secondary school spaces as defined in Building Bulletin 9814.
This can be used to identify the lighting required for particular space types.

Space types Lighting type Space types Lighting type

General teaching Performance
Seminar room A Music recital C
Classroom (including open plan A Music classroom C
and small lecture)
Music group/practice rooms C
Small group/interview room A
(FLA etc) Music ensemble rooms C
Recording studio C
Light practical
Recording studio control room C
ICT room A Drama studio C
Science laboratory B A/V studio (incl. video-conferencing) C
Large (textiles or 3D) and general B
(2D) art rooms Halls
Kiln room G 4-court sports hall D
Electronics and control systems B Activity studio (incl. gymnasium) D
Constructional textiles B Main assembly/multi-purpose hall D
Graphics room B Lecture theatre (over 50 people) D
Art/design resource area B Swimming pool D
Heavy practical Resource areas
Food technology B SEN resource base A15
Resistant materials (incl. CADCAM) B Small group room (SEN etc) A

14 www.teachernet.gov.uk/schoolbuildings
15 For further information, please refer to Building Bulletin 77, Designing for pupils with Special Educational Needs and Disabilities
in Schools.



Space types Lighting type Space types Lighting type

Resource areas Dining/social areas
Library resource centre and careers A16 Dining (hot meals) and E
sandwich/vending areas
Study areas (incl. sixth form) A
Social and common rooms E
Staff and administration (incl. sixth form)

Meeting room (incl. interview) A Catering facilities
SEN therapy/counselling/MI room A
Kitchen preparation areas G
Offices, general office (incl. ICT A
technician, caretaker) Kitchen staff and store rooms G

Staff rooms (social and work rooms A Toilets (and personal care)
and reprographics)
Entrance/reception Pupil and staff changing rooms G
E
and hygiene facilities
Storage Pupil and staff showers G
All walk-in stores for basic G Pupil, staff and visitors’ toilets G
teaching areas
Circulation
Science prep room B
Chemical store G Atria and circulation areas F
Multi-materials prep room B Plant
PE store G
Plant rooms G
Non-teaching stores (stock, G
secure, exam, community) Electrical cupboards and ducts G
Wheelchair/appliances ‘lay-bys’ and G Server rooms G
locker areas
Chair store G
Maintenance and cleaners’ stores G

16 Vertical illumination required for the book stacks.



Performance specifications Lighting type A: General (for most teaching
The lighting requirements for each type of and non-teaching areas)
space are given below. Teaching spaces
The activities taking place in teaching spaces
This does not preclude the designer from
fall into the following categories:
using other solutions to achieve particular
aesthetic or functional effects. However, it is • Presentations, where students sit addressed
recommended that the proposed lighting by a teacher or pupil speaking from a specific
meets the key performance requirements for location. In these rooms the lighting has three
the intended space. principal roles: to light the desks, the speaker
and the board (in new schools there are often
The examples below offer guidelines – interactive whiteboards)
it is for those involved to use their • Interactive learning, where teaching takes
own skills and expertise in deciding what the form of group discussion, where the
will be a reasonable and appropriate final teachers and the students might sit anywhere.
design solution in their particular situation. In these rooms the lighting needs to reveal
the space without creating shadows in any
Please refer to Tables 3 and 4 on pages 17 and part of the room.
18, which show the various ways of mounting The lighting in an informal teaching space
the luminaires and the different types of light should be gentle and unobtrusive. Luminaires
distribution. For more information on lamps, should be carefully chosen to provide a relaxed
please refer to Table 2 on page 15. atmosphere. Light switches should be
Well lit walls and ceilings, in addition to lighting accessible and flexible. In open plan teaching
on the working plane, both direct and indirect areas block switching is not suitable, as it does
lighting, can be achieved in many ways. not give sufficient flexibility. As face-to-face
For example: communication is important, lamps chosen
should be of good colour rendering.
1) a suspended luminaire that has both
upwards and downwards distribution Vertical surfaces should be illuminated as
2) a combination of ceiling luminaires that well as horizontal ones. Desktop illumination
provide upward lighting and wall-mounted should not be over emphasised and a
luminaires that provide downward lighting dedicated dimmable luminaire should be
3) ceiling luminaires that have some reflectors placed above the whiteboard to highlight
or diffusing elements suspended below the the area.
ceiling level that can reflect some light back
up onto ceiling.



Administrative offices and staff areas There is more detailed information in:
A wide range of tasks is carried out in a general
• CIBSE Lighting Guide LG3, for VDU Use
office. Almost any surface might be used for
Environments
reading, so vertical plane illuminance should
be considered as well as the horizontal. • CIBSE Lighting Guide LG7, Lighting for Offices
• BREEAM Schools Assessment Manual,
One of the main problems is unwanted
available from www.breeam.org/schools.html
reflections on computer screens, which can
be bright enough to make it difficult to • CIBSE Lighting Guide LG5, Lecture, Teaching
differentiate between screen characters and and Conference Rooms.
the background. Luminaires in offices with
high computer use should have a louvre or
other suitable type of control, with low
luminance above critical angles to prevent
glare on the screens.

Luminaires and windows with high illuminance
in directions affecting screens must be avoided.
Positive lighted screens – dark letters on a light
background – will have relatively high
brightness, which will significantly reduce the
effect of reflected images. Negative polarity
screens – light letters on a dark background –
will have relatively low brightness, and
reflections on the screen will make it difficult to
see the display. Negative polarity software is
now very uncommon except in specialist
applications such as some CAD programmes.
The vast majority of software used in schools
is positive polarity. Where negative polarity
programmes are in use special lighting design
will be required.



Libraries
The lighting of library spaces must be
co-ordinated with the furniture arrangement
but adaptable to a number of different
functions. As well as general lighting,
lighting for vertical book stacks, for study
and for browsing, and accent lighting for
display purposes may be required.

Performance requirements, type A

1 Maintained Illuminance at working plane 300 lux

2 Uniformity ratio Not less than 0.8

3 Limiting glare rating 19

4 Colour rendering (Ra) >80

Examples of type A lighting

Light Mounting type Lamp Control type
distribution
Both direct 1. Ceiling recessed and wall mounted Linear fluorescent Daylight linking,
and indirect & compact absence detection
2. Ceiling semi-recessed
fluorescent and central
3. Ceiling surface and wall mounted manual switches
for teaching and
4. Pendant (downlighting) and wall mounted
office areas.
5. Pendant (up and down light) Daylight linking
and central
manual switches
for library areas



Lighting type B: Practical High level general lighting can be used,
(where more light is required) or local task lighting supplementing the
Good lighting is particularly important for areas general lighting. Where there is fixed
where practical activities take place to help benching, adjustable bench lights may be
ensure that equipment is handled safely, and to suitable, particularly where directional
avoid accidents. People may be undertaking lighting is required. Luminaires should be
intricate tasks that need accurate readings and corrosion resistant, IP44 rated and complete
subtle observation, so higher light levels than with a diffuser.
general teaching areas would be appropriate. Art rooms are used for a large range of
activities, which might change throughout
the year. The main requirement is good
general lighting. The preference is for daylight
from north-facing windows and full availability
of directional lighting, particularly for sculpture
works and work involving texture. Some
additional flexible lighting for the display of
work may also be desirable. Luminaires should
be robust and complete with a prismatic or
opal diffuser to avoid damage to the lamp.
They should be minimum IP65 rated in order
to avoid water penetration at pressure.

For a typical science laboratory, preparation
room or food technology area, luminaires
should be complete with a prismatic or opal
diffuser. They should be minimum IP44 rated
to avoid water and/or moisture penetration.



Performance requirements, type B

1 Maintained illuminance at working plane 500 lux

2 Uniformity ratio Not less than 0.8


4 Colour rendering (Ra) >80*

Examples of type B lighting

distribution
Both direct 1. Ceiling recessed and wall mounted Linear fluorescent Daylight linking,
and indirect & compact absence detection
5. Pendant (up and down light)

Lighting type C: Performance (stage lighting It may be appropriate to install two or more
and lighting to enhance performing arts) independent lighting systems. Alternatively,
Performance spaces can be used for a wide a lighting installation that provides both
variety of activities, so there needs to be upward and downward light from separate
flexibility in their lighting, with the option lamps within the same luminaire could be
of luminaires being switched in groups. used. Switching of upward light can be
independent of downward light switching.

Performance requirements, type C


2 Uniformity ratio Not applicable


4 Colour rendering >80

* For art rooms there may be a requirement for higher colour rendering than Ra >90.



Examples of type C lighting

distribution
1. Ceiling recessed and wall mounted Linear fluorescent Daylight linking,
and compact absence detection
Both direct
and indirect 4. Pendant (downlighting) and wall mounted
6. Wall mounted (up and down light)

Performance spaces are often used for
theatrical/drama presentations with a defined
stage area, so the following additional
provisions may be necessary:

• lighting of the stage area should be separate
from lighting in the audience area
• lighting should be dimmable smoothly and
without flicker to 1% of its maximum level
• theatrical lighting installation may be needed, Lighting type D: Sports (for sports and
using professional spotlights rigged on multi-purpose halls)
standard industry tube and plugs and
Sports halls are relatively large spaces with
sockets. Essential locations are above the
high soffits. In these areas, access to overhead
stage parallel to the front curtain immediately
luminaires will require specialist equipment and
behind the curtain line, one metre in front of
should be addressed in the designer’s risk
the rear wall, and in between at 1m to 1.5m
assessment. The luminaires should also be
intervals. Each socket should be wired
robust and impact resistant.
individually to a theatre dimmer remote
control from the control room or area. Windows and rooflights can cause both
Publications on standards and general advice disability and discomfort glare to users,
about theatrical presentations are available from because of the sun. When daylight apertures
the Association of British Theatre Technicians17. are provided, there should also be screening
facilities for use when necessary.

To enhance the visual environment, luminaires
should give both upward and downward light.

There is more detailed information in the CIBSE
Lighting Guide LG4: Sports.
17 www.abtt.org.uk



Performance requirements, type D





Examples of type D lighting

distribution
Both direct 1. Ceiling recessed and wall mounted Linear fluorescent Daylight linking
and indirect or compact and central
fluorescent or manual switches
3. Ceiling surface and wall mounted metal halide*
6. Wall mounted (up and down light)

Lighting type E: Reception/social (for non- Entrance, dining and social areas require 175-
teaching areas where lighting can be 250 lux. If these areas are to be used for reading
more diverse) or discussions 300 lux will be required. In social
Lighting in an entrance area should be inviting areas the walls may be used for display lighting,
and welcoming. The entrance space usually so a dedicated system to highlight the walls
houses a reception desk and a display area. may be required.

There will need to be dedicated lighting In dining areas, food display lighting is usually
systems for the reception desk and to highlight located in the furniture.
display walls or cabinets. The reception area
will need local and dedicated switches.
Downlighters are not recommended over
reception desks as the lack of a diffuse
component of light makes lip-reading difficult.

Wall-mounted luminaires are preferable for
maintenance if the ceiling is high.

* Please note that metal halide lamps are not dimmable.



Performance requirements, type E

1 Maintained illuminance at working plane Entrance, dining and social areas 175-
250 lux Reception area 250-350 lux




Examples of type E lighting

distribution
Both direct & 1. Ceiling recessed and wall mounted Linear fluorescent Daylight linking
indirect or direct or compact if daylit space,
and highlighting fluorescent or manual central
3. Ceiling surface and wall mounted metal halide* switching and
time clock. Manual
local control to
5. Pendant (up and down light) reception desk in
6. Wall mounted reception areas




Lighting type F: Circulation
The purpose of the lighting in circulation areas
and stairs is to allow safe movement from one
place to another and to produce interesting
and stimulating spaces. Emergency lighting
should also be considered in the design of
these areas. Learning and study areas within
circulation should have lighting to Type A
performance requirements.

Stairs need to be well lit to avoid accidents.
The main consideration is to provide lighting
which ensures that the staircase treads and
risers are well defined, with a contrast between
treads and risers.

Wall-mounted luminaires are preferable for
maintenance if the ceiling is high.

Performance requirements, type F

1 Maintained illuminance at working plane 80-120 lux




Examples of type F lighting

distribution
Direct or indirect 1. Ceiling recessed Linear fluorescent, Daylight linking
compact and presence
2. Ceiling surface
fluorescent or detection
3. Wall mounted metal halide*




Lighting type G: Service areas (non-teaching In kitchens, toilets and changing rooms,
spaces such as storage areas and toilets luminaires should be complete with diffusers
Service areas such as kitchens, storage areas, and should be minimum IP44 rated to avoid
toilets, changing rooms, showers and plant water and/or moisture entering the luminaire.
rooms in secondary schools require different In shower areas, luminaires should be minimum
levels of illuminance and lighting control. IP55 rated. Robust luminaires are required.
In storage areas, luminaires should be complete In plant room areas, luminaires should be
with a prismatic or opal diffuser or wire guard to robust and complete with a prismatic or opal
avoid damage to the lamp. diffuser to avoid damage to the lamp.
Luminaires should be minimum IP65 rated in
order to avoid water penetration at pressure.

Performance requirements, type G

1 Maintained illuminance at working plane 500 lux in kitchens/200 lux in toilets and
plant rooms/100 lux in storage areas




Examples of type G lighting

distribution
Direct or indirect* 1. Ceiling surface Linear fluorescent Manual central
or compact switching for
2. Wall mounted*
fluorescent kitchens, absence
or presence
detection for all
other areas

* For toilet areas only.



References and glossary of terms

This document was published in For relevant lighting guidance,
September 2007. After this date recommendations and regulations,
please refer to the following:
readers should ensure they use
the latest edition for all references. • BREEAM Schools Assessment Manual,
available from www.breeam.org/schools.html
• Building Bulletin 76, BB 76, Maintenance
of Electrical Services, DCSF
• Building Bulletin 87, BB 87, Guidelines for
Environmental Design in Schools, DCSF,
from www.teachernet.gov.uk/energy
• Building Bulletin 98, BB 98, Briefing
Framework for Secondary School Projects.
• Building Bulletin 90, BB 90, Lighting Design
for Schools, DCSF, from
www.teachernet.gov.uk/lighting
• Building Bulletin 77, BB 77, Designing for
Pupils with Special Educational Needs
and Disabilities in Schools, DCSF



• The Code of Practice for the emergency lighting Glossary of terms
of premises, BS 5266 Brightness: attribute of the visual sensation
• Code for Lighting, CIBSE, SLL associated with the amount of light emitted
from a given area. It is a subjective correlate of
• Emergency escape lighting systems,
luminance. Technically defined as luminosity
BS EN 50172
(obsolete): attribute of a visual sensation
• Emergency lighting guide, LG12, CIBSE according to which an area appears to emit
• Lighting Guide LG3, for VDU use more or less light.
Environments, CIBSE
Colour rendering: a general expression for
• Lighting Guide LG7, Lighting for Offices, CIBSE the appearance of surface colours when
• Lighting GUIDE LG4, Sports Lighting, CIBSE illuminated by light from a given source
compared, consciously or unconsciously,
• Lighting Guide LG5, Lecture, Teaching and
with their appearance under light from
Conference Rooms, CIBSE
some reference source.
• Lighting Guide LG10, Daylighting and
Window Design, CIBSE Colour rendering index: A measure of the
degree to which the colours of surfaces
• Light and Lighting – Lighting of workplaces.
illuminated by a given light source conform to
Indoor workplaces, BS EN 12464
those of the same surfaces under a reference
• Luminaires for emergency lighting, illuminant, suitable allowance having been
BS EN 60598-2-22:1999 made for the state of chromatic adaptation.
• Part L2A Conservation of fuel and power in new
Colour temperature: all materials emit light
buildings other than dwellings. The Building
when heated. The temperature to which a full
Regulations 2000, edition 2006
radiator (or ‘black body’) would be heated to
• Part L2B Conservation of fuel and power achieve the same chromaticity (colour quality)
in existing buildings other than dwellings. of the light source being considered, defines
The Building Regulations 2000, edition 2006 the correlated colour temperature of the lamp,
quoted in degrees Kelvin.

Correlated colour temperature (CCT):
the temperature of a full radiator that emits
radiation having a chromaticity nearest to that
of the light source being considered. The unit
is the Kelvin, K.



Contrast: difference in the luminance or colour Illuminance (E): the luminous flux density at a
of two objects and their surroundings. The surface, indicated in lm/m2 or lux.
lower the contrast level the more difficult the
Average illuminance: illuminance averaged
visual task.
over the specified area. Unit: lux.
Daylight factor: the illuminance received at a Note: in practice this may be derived either
point indoors, from a sky of known or assumed from the total luminous flux falling on the
luminance distribution, expressed as a surface divided by the total area of the surface,
percentage of the horizontal illuminance or alternatively from an average of the
outdoors from an unobstructed hemisphere of illuminances at a representative number of
the same sky. Direct sunlight is excluded from points on the surface.
both values of illuminance.
Indirect lighting: lighting in which the greater
Efficacy (lamp): the quantity of light a light part of the flux reaches the surface (usually the
source emits per watt of electrical power of working plane) only after reflection at other
energy consumed. Note that both the lamp surfaces and particularly at the roof or ceiling.
luminous efficacy and the system (lamp and Luminaires with a flux fraction ratio greater than
control gear) luminous efficacy can be specified. 10 are usually regarded as indirect.
The system luminous efficacy is always lower
IP rating (ingress protection number): a two
then the lamp luminous efficacy.
digit number associated with a luminaire. The
Efficiency (luminaire): luminaire light first digit classifies the degree of protection the
output ratio. luminaire provides against the ingress of solid
foreign bodies. The second digit classifies the
Emergency lighting: the lighting provided for
degree of protection the luminaire provides
use when the supply to the normal mains
against the ingress of moisture.
lighting installation fails.
Limiting glare rating: the maximum value of
Glare: the discomfort or impairment of vision
the glare rating which is recommended for a
experienced when parts of the visual field are
specific lighting installation.
excessively bright in relation to the general
surroundings. Maintained illuminance: value below which
the average illuminance on the specified area
Glare rating: A numerical index calculated
should not fall. It is the average illuminance at
according to CIBSE Technical Memorandum
the time maintenance should be carried out.
TM10. It enables the discomfort glare from
Unit: lux.
lighting installations to be ranked in order of
severity and the permissible limit of discomfort Uniformity ratio: ratio of minimum illuminance
glare from an installation to be prescribed to average illuminance on a surface.
quantitively.



You can download this publication or order copies
online at: www.teachernet.gov.uk/publications
Search using the ref: 00648-2007FLR-EN
Copies of this publication can also be obtained
from: DCSF Publications
PO Box 5050
Sherwood Park
Annesley
Nottingham NG15 ODJ
Tel 0845 60 222 60
Fax 0845 60 333 60
Textphone 0845 60 555 60
Please quote ref: 00648-2007FLR-EN
ISBN: 978-1-84775-050-1
© Crown Copyright 2007
Published by the Department for Children,
Schools and Families
Extracts from this document may be reproduced
for non-commercial research, education or training
purposes on the condition that the source is
acknowledged. For any other use please contact
hmsolicensing@opsi.x.gsi.gov.uk

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