Lighting Guide 5: Lighting for education The Society of Light and Lighting 222 Balham High Road, London SW12 9BS, UK Tel: 020 8675 5211. Fax: 020 8673 3302. e-mail: This document is based on the best knowledge available at the time of publication. However, no responsibility of any kind for any injury, death, loss, damage or delay however caused resulting from the use of these recom - mendations can be accepted by the Chartered Institution of Building Services Engineers, the Society of Light and Lighting, the authors or others involved in its publication. In adopting these recommendations for use each adopter by doing so agrees to accept full responsibility for any personal injury, death, loss, damage or delay arising out of or in connection with their use by or on behalf of such adopter irrespective of the cause or reason therefore and agrees to defend, indemnify and hold harmless the Chartered Institution of Building Services Engineers, The Society of Light and Lighting, the authors and others involved in their publication from any and all liability arising out of or in connection with such use as aforesaid and irrespective of any negligence on the part of those indemnified. The rights of publication or translation are reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means without the prior permission of the publisher. © February 2011 The Society of Light and Lighting The Society is part of CIBSE which is a registered charity, number 278104. ISBN 978-1-906846-17-6 Layout and typesetting by CIBSE Publications. Printed in England by Charlesworth Press, Wakefield, West Yorkshire WF2 9LP Cover illustrations (clockwise from upper left): Warsaw University (photograph courtesy of Thorn Lighting); Southwell Minster School, Southwell, Nottinghamshire (photograph courtesy of Thorn Lighting); Excelsior Academy, Newcastle Upon Tyne (photograph courtesy of Cundall Light4); Usworth Sixthform College, Washington, Tyne And Wear (photograph courtesy of Thorn Lighting). Note from the publisher This publication is primarily intended to give guidance. It is not intended to be exhaustive or definitive, and it will be necessary for users of the guidance given to exercise their own professional judgement when deciding whether to abide by or depart from it. Any commercial products depicted or described within this publication are included for the purposes of illustration only and their inclusion does not constitute endorsement or recommendation by the Society. Printed on recycled paper comprising at least 80% post-consumer waste In 1963 the Illuminating Engineering Society published a remarkable Foreword monograph entitled Lecture theatres and their lighting, which became a standard work of reference. An updated edition was published in 1973 and then in 1991 it was updated and published as CIBSE Lighting Guide LG5: The visual environment in lecture, teaching and conference rooms. Within a very short period of time there were a vast array of CIBSE and Department for Education and Schools (DfES) guides available covering all manner of lighting in schools, teaching spaces, lecture theatres and the like, including documents such as Building Bulletin 90: Lighting design for schools. In 1995 an addendum to LG5 was issued to deal with changes in government funding for schools projects and changes in European legislation for workplace lighting. The Department for Children, Schools and Families (previously the DfES) decided in 2008 that it would join with the SLL in updating LG5 to include schools. This Lighting Guide covers not only lecture theatres, but also all teaching spaces and rooms specific to educational premises across schools and further education, and extends to committee rooms, conference and multi- purpose rooms. It represents a complete revision but includes relevant material from the original LG5 and BB90 working groups. Our thanks go to many of the original authors whose work is included here, which include R Aldworth, R Anderson, J Baker, L Bedocs, R Bell, C Bissell, K Gofton, J Lambert, D Loe, J Lynes, I MacLean, K Mansfield, J Mardaljevic, M Patel, V Rolfe, P Ruffles, A Tarrant, R Venning, L Watson and Professor A Wilkins. LG5 Task Group I D Macrae (Thorn Lighting) (Chairman) A Bissell (Cundall LLP) R Daniels (Department for Education) B Etayo (Fulcrum First LLP) S Fotios (Sheffield University) P Raynam (University College London) T Ramasoot (Sheffield University) Director of Information Jacqueline Balian Secretary to the Society of Light and Lighting Liz Peck Editor Ken Butcher Acknowledgement Permission to reproduce extracts from BS EN 15193, BS EN 12464-2, BS EN 1838 and BS EN 12464-1 (draft) is granted by BSI. British Standards can be obtained in PDF or hard copy formats from the BSI online shop: www.bsigroup.com/Shop, or by contacting BSI Customer Services for hardcopies only: tel: +44 (0)20 8996 9001, e-mail: Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 2 Components of lighting design . . . . . . . . . . . . . . . . .1 2.1 Objectives and constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 2.2 Lighting for visual function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 2.3 Lighting for visual amenity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 2.4 Lighting and architectural integration . . . . . . . . . . . . . . . . . . . . . . .4 2.5 Lighting and energy efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 2.6 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 2.7 Lighting costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 2.8 Lighting for health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 3 Lighting options . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 3.1 Natural lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 3.2 Electric lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 3.3 Integrated daylighting and electric lighting . . . . . . . . . . . . . . . . . .17 3.4 Lightness of the interior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 3.5 Room surface reflectance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 3.6 Lighting the interior space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 3.7 Mean cylindrical illuminance . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 3.8 Modelling index and directional light . . . . . . . . . . . . . . . . . . . . . . .22 4 Lighting design guidance . . . . . . . . . . . . . . . . . . . . .22 4.1 Daylighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 4.2 Electric lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 4.3 Integrated daylight and electric lighting . . . . . . . . . . . . . . . . . . . .35 4.4 Aids to lighting design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 5 Lighting for particular applications . . . . . . . . . . . . .37 5.1 Classification of teaching and conference spaces . . . . . . . . . . . . .37 5.2 General performance requirements for learning spaces . . . . . . . . .37 5.3 Lecture theatres and lecture rooms . . . . . . . . . . . . . . . . . . . . . . . .39 5.4 Teaching rooms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49 5.5 Large conference rooms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 5.6 Committee and meeting rooms . . . . . . . . . . . . . . . . . . . . . . . . . . .52 5.7 Multi-purpose rooms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53 5.8 Adjoining spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 5.9 Waiting areas and lobbies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56 5.10 Areas with display screen equipment . . . . . . . . . . . . . . . . . . . . . . .57 5.11 Laboratories, work shops and other practical learning spaces . . . .59 5.12 Libraries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60 5.13 Sports halls and gymnasia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61 5.14 General purpose halls, and drama and dance studios . . . . . . . . . .62 5.15 Lighting for whiteboards and projection screens . . . . . . . . . . . . . .63 5.16 Lighting and visual aids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64 5.17 Lighting for pupils with visual and hearing impairments . . . . . . . .65 5.18 Local task lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65 5.19 Exterior lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .66 5.20 Emergency lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70 6 Checklist for lighting design . . . . . . . . . . . . . . . . . .77 6.1 Task/activity lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77 6.2 Lighting and energy efficiency . . . . . . . . . . . . . . . . . . . . . . . . . . . .79 7 Lighting maintenance . . . . . . . . . . . . . . . . . . . . . . . .80 8 Management of lecture and conference spaces . . .81 8.1 Visual clutter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81 8.2 Lecture attendants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81 8.3 Communication between lecturer and projectionist or projector . .82 8.4 Projection rooms and booths . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82 8.5 Preparation and equipment rooms . . . . . . . . . . . . . . . . . . . . . . . .82 8.6 Problems for visiting lecturers . . . . . . . . . . . . . . . . . . . . . . . . . . . .82 8.7 Lectures involving demonstrations . . . . . . . . . . . . . . . . . . . . . . . . .83 9 Lighting costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83 9.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83 9.2 Emergency lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83 10 Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83 10.1 Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83 10.2 Control gear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83 10.3 Lighting controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86 10.4 Disposal of used lighting equipment . . . . . . . . . . . . . . . . . . . . . . .88 11 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98 Appendix A1: luminance limits and . . . . . . . . . . .100 display screen equipment Introduction 1 Learning, whether by discussion, interaction, practical application or formal 1 Introduction lecture, requires sufficient light to enable the pupils to see the visible information presented around them. Whether in a primary school classroom or a professional lecture theatre, whether for young or old, the quality of light we choose to provide in the learning environment will directly affect our learning experience and indeed our motivation to learn. If we cannot see clearly what is written on the board, identify true colours, or read the facial expression and body language of our teacher, then our learning and our experience will fail to meet our needs. Above all aspects we can create in a learning space, that of the lighting affects us most. Harsh light creating aggressive facial modelling, or excessive daylight urging the teacher to draw the blinds and use electric light, impact upon us and our environment. More so now than at any other time in the history of lighting, we have to create stimulating and sustainable learning environments. The function of this Lighting Guide is to offer advice on the lighting of educational spaces (specifically those not covered elsewhere), lecture theatres, teaching rooms, conference rooms and multi-purpose rooms, and on the visual problems that may arise. It is therefore necessary to discuss other matters than simply the lighting equipment and its positioning. The decoration and finishes of such rooms, the sightlines, the positioning of lighting controls and access doors all need to be taken into account. The lighting is a vital element in such rooms and requirements of lighting should be taken into account from the first stages of the planning. This point cannot be too strongly emphasised. Light is so important to the functioning of all the premises covered by this Lighting Guide that it must be considered from the very outset of the planning process. As lighting design is such a vital part of the success and performance of both space and student the designer of such spaces must be able to demonstrate clearly their competence in lighting design for such spaces either by qualification or experience. By ‘lighting’ it is important to stress that we mean both natural and electric lighting; experience shows that whilst much thought is given to natural lighting, i.e. window design, planning for electric lighting is often left until far too late in the design process. Equally, developments driving sustainable buildings have often led to natural lighting schemes that introduce other problems such as overheating, glare and so on. That said, natural lighting should be used as far as possible as the primary light source in all teaching environments. There will be exceptions where daylight needs to be excluded but these are few and in most cases simple and functional control of daylight ingress when required will suffice. Lighting design can have many different objectives. Ideally, these objectives are 2 Components determined by the client and the lighting designer in collaboration and cover of lighting both outcomes and costs (Figure 2.1). The most common objective for a lighting installation is to allow the users of a space to carry out their work quickly and design accurately, without discomfort. However, this is a rather limited view of what a lighting installation can achieve. For educational spaces, the objective of lighting is to facilitate the learning of students by passing on information from 2.1 Objectives and the teacher or lecturer and via other media. For these tasks the requirements of the lecturer will often be different from those of the pupils. In lecture theatres constraints the task of presenting may require dimmed lighting to enable clear images on the screen, but the need to take notes may require increased lighting levels, particularly for those with impaired sight. Educational sport facilities are lit at night to encourage their use in the wider community, but in doing so they may impinge upon the residential areas surrounding the school. Most lighting installations have to serve multiple functions. When designing lighting it is always desirable at the outset of the project to identify all the functions that the lighting is expected to fulfil. Introduction 1 Learning, whether by discussion, interaction, practical application or formal 1 Introduction lecture, requires sufficient light to enable the pupils to see the visible information presented around them. Whether in a primary school classroom or a professional lecture theatre, whether for young or old, the quality of light we choose to provide in the learning environment will directly affect our learning experience and indeed our motivation to learn. If we cannot see clearly what is written on the board, identify true colours, or read the facial expression and body language of our teacher, then our learning and our experience will fail to meet our needs. Above all aspects we can create in a learning space, that of the lighting affects us most. Harsh light creating aggressive facial modelling, or excessive daylight urging the teacher to draw the blinds and use electric light, impact upon us and our environment. More so now than at any other time in the history of lighting, we have to create stimulating and sustainable learning environments. The function of this Lighting Guide is to offer advice on the lighting of educational spaces (specifically those not covered elsewhere), lecture theatres, teaching rooms, conference rooms and multi-purpose rooms, and on the visual problems that may arise. It is therefore necessary to discuss other matters than simply the lighting equipment and its positioning. The decoration and finishes of such rooms, the sightlines, the positioning of lighting controls and access doors all need to be taken into account. The lighting is a vital element in such rooms and requirements of lighting should be taken into account from the first stages of the planning. This point cannot be too strongly emphasised. Light is so important to the functioning of all the premises covered by this Lighting Guide that it must be considered from the very outset of the planning process. As lighting design is such a vital part of the success and performance of both space and student the designer of such spaces must be able to demonstrate clearly their competence in lighting design for such spaces either by qualification or experience. By ‘lighting’ it is important to stress that we mean both natural and electric lighting; experience shows that whilst much thought is given to natural lighting, i.e. window design, planning for electric lighting is often left until far too late in the design process. Equally, developments driving sustainable buildings have often led to natural lighting schemes that introduce other problems such as overheating, glare and so on. That said, natural lighting should be used as far as possible as the primary light source in all teaching environments. There will be exceptions where daylight needs to be excluded but these are few and in most cases simple and functional control of daylight ingress when required will suffice. Lighting design can have many different objectives. Ideally, these objectives are 2 Components determined by the client and the lighting designer in collaboration and cover of lighting both outcomes and costs (Figure 2.1). The most common objective for a lighting installation is to allow the users of a space to carry out their work quickly and design accurately, without discomfort. However, this is a rather limited view of what a lighting installation can achieve. For educational spaces, the objective of lighting is to facilitate the learning of students by passing on information from 2.1 Objectives and the teacher or lecturer and via other media. For these tasks the requirements of the lecturer will often be different from those of the pupils. In lecture theatres constraints the task of presenting may require dimmed lighting to enable clear images on the screen, but the need to take notes may require increased lighting levels, particularly for those with impaired sight. Educational sport facilities are lit at night to encourage their use in the wider community, but in doing so they may impinge upon the residential areas surrounding the school. Most lighting installations have to serve multiple functions. When designing lighting it is always desirable at the outset of the project to identify all the functions that the lighting is expected to fulfil. 2 Lighting Guide 5: Lighting for education Fig. 2.1 Objectives, outcomes and costs Visual function Architectural Visual integration amenity Lighting design Costs Energy (capital and efficiency operating) Installation maintenance As for constraints, an important aspect of lighting design is the need to minimise the amount of electricity consumed, for both financial and environmental reasons. It is also necessary to consider the sustainability of the lighting equipment. This means using materials that can be easily replaced and considering to what extent the equipment can be recycled at the end of its life. The financial costs, particularly the capital cost, are always an important constraint. No one wants to pay more for something than is absolutely necessary so the lighting designer needs to be able to justify the proposal in terms of value for money. 2.1.1 A holistic strategy A holistic strategy for lighting design is necessary because without it important benefits will be lost, and money and human resources will be wasted. The for lighting starting point is an in-depth conversation with the client and other members of the design team to formulate a design brief. This from a ‘whole building’ design perspective needs to branch out from natural and electric lighting to include the effects on thermal loading, ventilation and acoustics. At such a discussion, it will be necessary to address such fundamental questions as: what do you want to see and what do you not want to see, what is the function of the space, what is the proposed architectural style, and what is the budget? More formally, six distinct aspects of lighting need to be considered. They are: legal requirements, visual function, visual amenity, architectural integration, energy efficiency and sustainability All these aspects will contribute to the success of a design, but they may not all carry equal weight depending on the particular application and situation. Also there is no particular order in which they should be considered. The important issue is that all the elements are considered at the inception of the project and again at each key stage of the design process, perhaps more than once, for a satisfactory solution to emerge. 2.1.2 Legal requirements There are a number of legal requirements that apply to all lighting installations. Some are general, e.g. the Construction (Design and Management) (1) Regulations . Some are specific about the type and form the lighting that should be provided, e.g. emergency lighting in buildings (see chapter 9). Others influence lighting design by the limits they place on the type or amount of (2–4) equipment that can be used, e.g. Building Regulations . Details of the requirements of the Construction (Design and Management) Regulations can be obtained from Health and Safety Executive publications. It is essential that the designer and the client are aware of the relevant legal requirements. (5) The Education (School Premises) Regulations specify minimum standards for the premises of all maintained schools in England and Wales. The Components of lighting design 3 (6) publication Standards for School Premises , provides guidance on the School Premises Regulations. Some of the provisions of the School Premises Regulations also apply to independent schools. Guidance on legislation applying to independent schools is included in the Department for Education’s Registration of Independent Schools (7) Information pack . As the UK devolves central government control to individual countries there may be other Regulations under similar titles to be considered. (2–4) Schools are covered by the Building Regulations . In some cases, DfES Building Bulletins are referred to in Building Regulations Approved Documents. Except in these cases, or as otherwise stated, these publications are non-statutory. This aspect is related to the lighting required for doing tasks without discom - 2.2 Lighting for fort. Recommended illuminance for different tasks is given in the Code for visual function (8) (9) Lighting and the SLL Handbook , as well as in chapters 5 and 6 of this Lighting Guide. These values apply to the task area and do not necessarily need to apply to the whole working plane. Establishing which values apply to which task needs to be done with knowledge of how the space will function both now and in the future, where this information is available. Equally it is a decision that needs to be made with cognisance of all other aspects of the lighting and building design. The traditional way of lighting a work place has been a regular array of luminaires. For this approach, minimum task illuminance uniformity (minimum/average task illuminance ≥ 0.7) is recommended. This approach has the benefit that the tasks can be carried out on the horizontal plane anywhere in the work place but does tend to over-light areas not used for the primary task that happen to fall within an imaginary work plane. It should be noted that a more visually appealing and stimulating space can be created with additional energy saving benefits if the lighting is focused where it is needed. See sections 2.3 and 2.5. In some cases the task will have a colour recognition element. In such cases it will be necessary to use lamps with a high colour rendering index (CRI). For such tasks it will is appropriate to use lamps with a CRI ≥ 80 but for tasks with a requirement for very good colour discrimination, lamps with a CRI ≥ 90 will be necessary. The human visual system can adapt to a wide range of luminance but it can cope with only a limited luminance range at any single adaptation state. When this range is exceeded, glare will occur. If a field of view contains bright elements that cause glare it is likely that they will affect performance, or at least cause stress and fatigue which, in turn, will cause problems. To avoid this will mean using luminaires and windows that have limited luminance within the normal fields of view relative to the adaptation level. Glare limits for different (8) (9) tasks are given in the Code for Lighting and the SLL Handbook , as well as in chapters 5 and 6 of this Lighting Guide. There is no doubt that lighting can add visual amenity to a space that can give 2.3 Lighting for pleasure to the occupants but whether this provides a more tangible visual amenity (10) performance benefit is uncertain . Studies have shown that people respond to the lit appearance of a room on two independent dimensions, visual lightness (11–13) and visual interest . Visual lightness describes the overall lightness of the space, which is related to the average luminance of vertical surfaces. Visual interest refers to the non-uniformity of the illumination pattern or the degree of ‘light and shade’. People prefer some modulation in the light pattern rather than an even pattern of illumination, the magnitude of the modulation depending on the application. There is some evidence that visual lightness and visual interest are inversely correlated (Figure 2.2). 4 Lighting Guide 5: Lighting for education Fig. 2.2 Map showing the possible High locations of three application areas on a schematic diagram linking subjective impressions of Leisure visual interest and visual lightness Education and commercial Industrial Low Low High Visual lightness (brightness) Although variation in the light pattern is desirable, it has to be seen as meaningful in terms of the application and the architecture. To provide random patches of light in an uncoordinated way for no reason other than to provide light variation would be a poor design solution. Acceptable examples could be highlighting displays within a retail outlet, or a floral display in a hotel lobby. There remains one further area of visual amenity that needs to be considered and that is the colour appearance of the light. A light source with a correlated colour temperature (CCT) ≤ 3000 K will appear warm, and if it has a (9) CCT ≥ 5300 K it will appear cold (see the SLL Handbook , section 1.4.3). Where on this scale from warm to cool the colour appearance should fall will depend on the nature of and finishes in the space. In domestic situations a warm colour appearance will be required but in educational interiors a CCT of around 4000 K is appropriate as it blends reasonably well with daylight. The designer should be wary of the names applied to light sources as these can be misleading and differ between manufacturers. The best way to choose colour appearance is through practical trials. There is still much to learn about design for visual amenity but it would be negligent to ignore it. The best way to develop an understanding of visual amenity is though personal observations and trial installations. All elements of a lighting installation form part of the architecture or the 2.4 Lighting and interior design of a building. Understanding the space will be important when architectural deciding what sort of lighting is to be employed. The dimensions, finishes, integration texture, colour, materials and the atmosphere to be created are among some of the attributes that should be considered. The most appropriate place to start is with the daylighting, given the positive impact that well designed sunlit and daylit learning spaces have on the (14) ability for individuals to learn and develop . The windows and roof lights are a fundamental element of the fabric of the building. This means considering the amount and pattern of daylight required for the particular application, and hence the size and positions of windows and rooflights. But windows cannot be designed on the basis of the daylighting alone and other visual, thermal, acoustic and privacy issues need to be addressed. There is a clear hierarchy for successful environm ental design: (1) Daylight design. (2) Prevention of summertime overheating. (3) Design of ventilation. (4) Acoustic design. Visual interest (degree of light non-uniformity)