Lighting Guide 4: Sports Lighting The Society of Light and Lighting 222 Balham High Road, London SW12 9BS, UK Tel: 020 8675 5211. Fax: 020 8673 3302. e-mail: [email protected]. www. sll.org.uk The Society of Light and Lighting is part of the Chartered Institution of Building Services Engineers This document is based on the best knowledge available at the time of publica- tion. However, no responsibility of any kind for any injury, death, loss, damage or delay however caused resulting from the use of these recommendations 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 irre- spective 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 publica- tion 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. 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. 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. © October 2006 The Society of Light and Lighting Thanks are due to the following organisations for permission to use photo- graphs: Loughborough University: Figures 7, 11, 12, 15, 16, 20, 23, 25 National Cricket Centre (Loughborough University): Front cover, Figure 9 English Institute for Sport: Figures 6, 24 Sheffield Arena: Figure 19 Arup Sport (Commonwealth Stadium): Figure 28 Kempton Park Racecourse: Front cover, Figure 18 Photographs were provided by Abacus Lighting, Philips Lighting, Thorn Lighting and Dr N A Smith The Society is part of CIBSE which is a registered charity, number 278104. ISBN-10 1-903287-78-2 ISBN-13 978-1-903287-78-1 Typeset by JQ Editorial Services. Printed in England by Latimer Trend & Co Ltd., Estover Road, Plymouth PL6 7PY. Foreword This revised Lighting Guide replaces the LG4 Lighting Guide: Sports Lighting published in 1990. Recommendations within this guide have been aligned to the British Standard and European Norm BSEN 12193:1999. In updating the infor- mation note has been taken of new and emerging sports that were not included in the 1990 guide or BSEN 12193:1999 but which are played in the UK, and of proposed amendments to BSEN 12193. The sport requirements and recommendations have been changed to give specif- ic information relating to good lighting practice for each individual sport. Tabulated lighting parameters are provided for each sports application relative to the new system of lighting classes. There is additional information regarding colour television (CTV) group categories and colour rendering index recommen- dations. The revised guide is now in four parts. Part A: Principles of lighting with respect to sport Part B: Specific lighting requirements for individual sports (indoor and outdoor) Part C: Maintenance and operation of sports lighting Part D: Specification of equipment for sports lighting As before, the aim of the guide is to create design flexibility while achieving basic lighting requirements for each sport. Task group KJ Austin (Chairman) MD Simpson PA Blackburn DW Bosher Dr NA Smith Contents Foreword 1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2 Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.1 Colour, brightness and reflectance . . . . . . . . . . . . . . . . . . . . . . . .7 2.2 Illuminance requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 2.3 Light distribution, uniformity and illuminance gradient . . . . . .9 2.4 Glare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9 2.4.1 Glare rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 2.4.2 Unified Glare Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 2.5 Requirements for sport played by the visually impaired . . . . .11 2.6 Daylight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 2.7 Ancillary areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 2.8 Emergency lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 2.8.1 Emergency escape lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 2.8.2 Standby lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 2.8.2.1 Safety lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 2.8.2.2 Continuation of an event . . . . . . . . . . . . . . . . . . . . . . . .12 2.9 Surveillance lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 2.10 Planning requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 2.10.1 Obtrusive light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 2.11 Definitions of playing areas . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 2.12 Safety and protection of luminaries . . . . . . . . . . . . . . . . . . . . .14 3 Specific sports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 3.1 Archery ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 3.2 Athletics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 3.3 Badminton (indoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 3.4 Baseball . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 3.5 Basketball . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 3.6 Bowls (indoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 3.7 Bowls (outdoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 3.8 Bowling (nine or ten pin) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 3.9 Boxing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 3.10 Canoe slalom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 3.11 Cricket (outdoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 3.12 Cricket (indoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 3.13 Cricket (indoor training nets) . . . . . . . . . . . . . . . . . . . . . . . . . . .20 3.14 Curling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 3.15 Cycle racing (track) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 3.16 Dancing/aerobics/keep fit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 3.17 Darts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 3.18 Equestrian sports (indoor and outdoor) . . . . . . . . . . . . . . . . . .22 3.19 Fencing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 3.20 Five-a-side football (indoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 3.21 Fitness training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 3.22 Football (American) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 3.23 Football (association) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 3.24 Football (Gaelic) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 3.25 Golf courses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25 3.26 Golf driving ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 3.27 Greyhound racing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 3.27.1 Low-mounting system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 3.27.2 High-mounting system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 3.28 Gymnastics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29 3.29 Handball (indoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 3.30 Hockey (indoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 3.31 Hockey (outdoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 3.32 Horse racing (gallop and trotting) . . . . . . . . . . . . . . . . . . . . . . .31 3.33 Hurling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 3.34 Ice hockey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 3.35 Ice sports (artistic) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34 3.36 Lawn tennis (indoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34 3.37 Lawn tennis (outdoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 3.38 Martial arts (including aikido, judo, karate, kendo etc) . . . . . .35 3.39 Netball . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36 3.40 Rugby (league and union) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36 3.41 Shooting (indoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 3.42 Skiing (artificial slopes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 3.43 Snooker and billiards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37 3.44 Speed skating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38 3.45 Speedway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38 3.46 Squash (rackets and raquetball) . . . . . . . . . . . . . . . . . . . . . . . . .39 3.47 Swimming (all activities) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 3.47.1 Indoor pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 3.47.2 Outdoor pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 3.47.3 Underwater lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 3.48 Table tennis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41 3.49 Volleyball (indoor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 3.50 Wall climbing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 3.51 Weight training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 3.52 Wrestling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .42 4 Sports halls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 5 Stadia – small and large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44 5.1 Small sports stadia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44 5.1.1 Track and field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .45 5.1.2 Track only . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 5.1.3 Central field . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 5.2 Large sports stadia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 5.2.1 Training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 5.2.2 Normal events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46 5.2.3 Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47 6 Indoor arenas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47 6.1 Sports lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 6.2 Broadcast lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 6.3 Developing the design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 6.4 Set-up lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .48 6.5 Lighting of spectator areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49 7 Lighting for television . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49 7.1 Illuminance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49 7.2 Uniformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .50 7.3 Colour parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51 7.3.1 Colour temperature and correlated colour temperature . . . . . . . . .51 7.3.2 Colour rendering index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51 7.4 Additional requirements for film . . . . . . . . . . . . . . . . . . . . . . . .51 7.5 Display screens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51 7.6 Requirements for non-broadcast-quality video . . . . . . . . . . . .51 7.7 Requirements for HDTV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51 8 Maintenance and operation . . . . . . . . . . . . . . . . . . . . . . . . . .52 8.1 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52 8.2 Depreciation of lighting installations . . . . . . . . . . . . . . . . . . . .52 8.3 Construction of equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . .52 8.4 Servicing equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .52 8.5 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53 8.5.1 Energy use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53 8.5.1.1 Lamp energy efficiency class . . . . . . . . . . . . . . . . . . . . . .53 8.6 Management of lighting systems . . . . . . . . . . . . . . . . . . . . . . . .53 8.6.1 Flexibility of switching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53 8.6.1.1 Occupancy detectors . . . . . . . . . . . . . . . . . . . . . . . . . . . .53 8.6.2 Constant illuminance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53 8.6.3 Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54 8.7 Hours of use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .54 9 Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 9.1 Lamp types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 9.2 Apparent colour of emitted light . . . . . . . . . . . . . . . . . . . . . . .55 9.3 Colour rendering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 10 Luminaire selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .55 10.1 Protection classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56 10.2 Electrical classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56 10.3 Resistance to impact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56 10.4 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56 10.5 Luminaire performance data . . . . . . . . . . . . . . . . . . . . . . . . . . .57 Appendix 1 – Determining average illuminance and uniformity ratio for sports installations . . . . . . . . . . . . . . . . . . . . . .58 Appendix 2 – Lighting depreciation factors . . . . . . . . . . . . . . . . . . . .60 Appendix 3 – Aiming floodlights and commissioning sports floodlighting installations . . . . . . . . . . . . . . .62 Appendix 4 – Relevant sport governing bodies . . . . . . . . . . . . . . . . .64 Appendix 5 – Typical play area dimensions . . . . . . . . . . . . . . . . . . . .65 Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78 Lighting Guide 4: Sports Lighting 7 Part A: Principles This guide is concerned with the lighting of sports areas and other playing and 1 Scope recreational areas. Specific recommendations for individual sports are given in section 3 of the guide. The requirements of large multi-purpose venues and specific provision for television broadcasting are provided in sections 4–7. The general information and lighting levels provided in the guide are aligned to the requirements of the British and European standard BSEN 12193:1999. 2 Requirements Sports and sports areas should be lit so that those taking part and those watch- ing, whether at the event or on television, can see clearly all that is going on. This calls for suitable brightness and contrast over the playing area, sufficient light at all points, correct distribution of light and adequate control of glare. Playing objects will be seen because they contrast with their background in brightness, colour or both. The more marked the contrast, the more clearly objects are per- ceived in general. There are additional special requirements for television trans- mission which are discussed in section 7. 2.1 Colour, Colour contrast is important in some sports and the choice of surface colours for brightness and interiors can help to make the object more visible. The brightness of a surface depends on how much light it receives and how this light is reflected from it – reflectance ie on its illuminance and its reflection properties. In principle, therefore, bright- ness contrasts can be controlled by adjusting the reflectance and illuminance for both the object and the background. In practice, however, there are often restric- tions on what can be done, especially outdoors. For example, as the reflection properties of a sports pitch cannot be altered, the illuminance is the main mech- Figure 1 (Below left) The tennis anism used to improve contrast. There is usually more freedom indoors. For ball can be clearly seen in instance, the reflectance and illuminance of tennis court surfaces can be speci- contrast to the dark green fied, and so produce the background needed for the ball to be seen clearly in sil- background. The lower wall reflectance is 0.2. houette (see figures 1 and 2). Figure 2 (Above right) Insufficient Reflectance values and types of surface materials used must be taken into contrast between ball and account in the design. The reflectance and colour of the surroundings and back- background makes it ground of a light source will also influence the amount of discomfort experi- difficult to see. The upper enced. wall reflectance is 0.5. 2.2 Illuminance The determination of how much light is required to play any given sport requirements depends upon several factors, some of which can be assessed with a degree of sci- entific and/or clinical accuracy. Contributing factors include: Lighting Guide 4: Sports Lighting 7 Part A: Principles This guide is concerned with the lighting of sports areas and other playing and 1 Scope recreational areas. Specific recommendations for individual sports are given in section 3 of the guide. The requirements of large multi-purpose venues and specific provision for television broadcasting are provided in sections 4–7. The general information and lighting levels provided in the guide are aligned to the requirements of the British and European standard BSEN 12193:1999. 2 Requirements Sports and sports areas should be lit so that those taking part and those watch- ing, whether at the event or on television, can see clearly all that is going on. This calls for suitable brightness and contrast over the playing area, sufficient light at all points, correct distribution of light and adequate control of glare. Playing objects will be seen because they contrast with their background in brightness, colour or both. The more marked the contrast, the more clearly objects are per- ceived in general. There are additional special requirements for television trans- mission which are discussed in section 7. 2.1 Colour, Colour contrast is important in some sports and the choice of surface colours for brightness and interiors can help to make the object more visible. The brightness of a surface depends on how much light it receives and how this light is reflected from it – reflectance ie on its illuminance and its reflection properties. In principle, therefore, bright- ness contrasts can be controlled by adjusting the reflectance and illuminance for both the object and the background. In practice, however, there are often restric- tions on what can be done, especially outdoors. For example, as the reflection properties of a sports pitch cannot be altered, the illuminance is the main mech- Figure 1 (Below left) The tennis anism used to improve contrast. There is usually more freedom indoors. For ball can be clearly seen in instance, the reflectance and illuminance of tennis court surfaces can be speci- contrast to the dark green fied, and so produce the background needed for the ball to be seen clearly in sil- background. The lower wall reflectance is 0.2. houette (see figures 1 and 2). Figure 2 (Above right) Insufficient Reflectance values and types of surface materials used must be taken into contrast between ball and account in the design. The reflectance and colour of the surroundings and back- background makes it ground of a light source will also influence the amount of discomfort experi- difficult to see. The upper enced. wall reflectance is 0.5. 2.2 Illuminance The determination of how much light is required to play any given sport requirements depends upon several factors, some of which can be assessed with a degree of sci- entific and/or clinical accuracy. Contributing factors include: 8 Lighting Guide 4: Sports Lighting – the size of the playing object; – the viewing distance; – the speed of the activity; – the contrast sensitivity; – adaptation; – the directional qualities of the incident light; – the reflectance of surfaces to be illuminated; and – the atmospheric and environmental factors. Visual acuity normally applies when the observer and visual task are both static. In sport it is more likely that either the observer and/or the visual task are moving, in which case we must consider dynamic visual acuity, ie the ability to discern detail when the observer, the visual task or both are in motion. It is also important to consider the effects of adaptation. The effect of a stim- ulus on the human visual system is not constant since it will be influenced by the state of adaptation of the retina at the instant the stimulus is introduced into the field of view. In essence, two forms of adaptation exist: dark adaptation and light adaptation. It can be shown that, when an individual is light adapted and then suddenly introduced into a dark environment, the time taken for the eyes to adapt is considerably longer than it is when the situation is reversed, ie when suddenly traversing from a dark environment to a light one. This phenomenon can have a major influence, particularly when there are inconsistencies in the ‘evenness’ of lighting. Levels of illuminance for outdoor sports provided by artificial light sources are usually lower than for the same sport when played indoors. Similarly, illumi- nances for outdoor sports under artificial lighting are usually lower than the level of prevailing daylight in which the same sport is played. This is due to the corresponding improvement in contrast and adaptation that occurs when view- ing a lit surface against a dark background such as the night sky. The illuminances stated are maintained values and apply to the principal playing area (PA). Where a sport has specified total area (TA) playing dimen- sions, the illuminance requirements over the total area should be a minimum of 75% of that provided for the principal area (PA) (see section 2.11). The velocity of a moving object also influences the lighting requirements for sport. Any lit object passing before the eyes excites the light-sensitive cones on the retina. However, if the object is moving relatively rapidly the number of cones excited at any one instant is relatively small, and therefore the object must be well illuminated for efficient vision. The illuminances specified are those values measured on a horizontal plane, based primarily upon the needs of participants. However, there is a need to pro- vide an adequate vertical component. The illuminance on principal vertical planes should not be less than 30% of the horizontal level. The illuminances referred to are those applicable to someone approximately 40 years old. No account has been taken of the changes in the ageing eye, which can be sub-divided into perceptual and physical changes. Figure 3 shows the typ- ical change in illuminance requirements as a function of age. 18 Figure 3 Typical relationship between the relative 16 illuminance requirement 14 and the age of the ce n 12 individual a n mi 10 u e ill 8 v ati 6 el R 4 2 0 0 10 20 30 40 50 60 70 80 Age of individual in years Part A: Principles – Requirements 9 The level of sport competition/participation and class of play will be used to determine the recommended minimum illuminance required. The higher the standard of play and the longer the spectator viewing distance, the higher the lighting class. Due to the nature of some levels of competition and lighting class- es, there may be overlap in specified minimum illuminances. Lighting class I – International and national competition – Large spectator capacities with long viewing distances – Top-level supervised training Lighting class II – Mid-level competition; principal local clubs and county regional competition – Medium spectator capacities with medium viewing distances – High-level supervised training Lighting class III – Low-level competition; local or small club competition – Minimal or no spectator provision – General training; school sports and recreational activities Table 1: Selection of lighting class Level of competition Lighting class I II III International and national * Regional and county * * Principal clubs * * * Small clubs * * General training, recreational and school sports * 2.3 Light Ideally, playing surfaces should appear uniformly bright when viewed from rel- distribution, evant directions. How far this can be achieved in practice depends on the reflec- tion properties of the surface and how it is illuminated. uniformity and The first step is usually to design for an acceptable uniformity of illuminance illuminance as expressed by the recommendation for the sport. These are minimum values. gradient All uniformities specified are defined as the minimum-to-average illuminance over the area, where these illuminance values are calculated at the specific grid points. In some sports an illuminance gradient may be specified to ensure that the rate of change of uniformity is acceptable. This is usually associated with the avoidance of banding or acute patchiness on the playing surface. The resulting uniformity of brightness depends on the reflection properties of the surface as well as on the uniformity ratio. With grass, for example, it depends on the angles at which the light falls on the grass, the direction from which the surface is viewed, the ways in which the grass has been cut and rolled and whether the ground is wet or dry. The effects of irregular surface reflection can seldom be estimated by calcu- lation alone. It is important to remember that the appearance of the lit playing surface may not relate to the illumination pattern and is influenced by viewing direction. The lit space above the playing area should be reasonably uniform. If not, playing objects will appear to accelerate as they pass from a light to a dark zone, causing difficulties in judging flight and speed. 2.4 Glare Glare may either impair vision (disability glare) or cause discomfort (discomfort glare). As both forms can occur simultaneously or separately, the control of glare is therefore a major factor to be considered in defining lighting. In sports applications, direct discomfort glare is generally caused by high- brightness light sources coming into a participant’s field of view. Minimising this may require special attention to the selection, positioning and screening of light sources and the use of diffusers, reflectors, refractors and similar devices on