IESNA G-1-03 Guideline for Security Lighting for People, Property, and Public Spaces The L AIGUHTTHIONRGITY® IESNA G-1-03 Guideline for Security Lighting for People, Property, and Public Spaces Publication of this Committee Report has been approved by the IESNA. Suggestions for revisions should be directed to the IESNA. Prepared by: IESNA Security Lighting Committee Copyright 2003 by the Illuminating Engineering Society of North America Approved by the IESNA Board of Directors, March 1 , 2003 as a Transaction of the Illuminating Engineering Society of North America. All rights reserved. No part of this publication may be reproduced in any form, in any electronic retrieval system or otherwise, without prior written permission of the IESNA. Published by the Illuminating Engineering Society of North America, 120 Wall Street, New York, New York 10005. IESNA Standards and Guidelines are developed through committee consensus and produced by the IESNA Office in New York. Careful attention is given to style and accuracy. If any errors are noted in this document, please forward them to Rita Harrold, Director Educational and Technical Development, at the above address for verifi- cation and correction. The IESNA welcomes and urges feedback and comments. ISBN # 0-87995-190-7 Printed in the United States of America. DISCLAIMER IESNA publications are developed through the consensus standards development process approved by the American National Standards Institute. This process brings together volunteers representing varied view- points and interests to achieve consensus on lighting recommendations. While the IESNA administers the process and establishes policies and procedures to promote fairness in the development of consensus, it makes no guaranty or warranty as to the accuracy or completeness of any information published herein. The IESNA disclaims liability for any injury to persons or property or other damages of any nature whatso- ever, whether special, indirect, consequential or compensatory, directly or indirectly resulting from the pub- lication, use of, or reliance on this document In issuing and making this document available, the IESNA is not undertaking to render professional or other services for or on behalf of any person or entity. Nor is the IESNA undertaking to perform any duty owed by any person or entity to someone else. Anyone using this document should rely on his or her own indepen- dent judgment or, as appropriate, seek the advice of a competent professional in determining the exercise of reasonable care in any given circumstances. The IESNA has no power, nor does it undertake, to police or enforce compliance with the contents of this document. Nor does the IESNA list, certify, test or inspect products, designs, or installations for compliance with this document. Any certification or statement of compliance with the requirements of this document shall not be attributable to the IESNA and is solely the responsibility of the certifier or maker of the statement. IESNA G-1-03 Prepared by the Security Lighting Committee, and Sub-Committee on Relationship Between Lighting and Crime, Illuminating Engineering Society of North America. Committee Members: David L. Salmon, Ph.D., CPO, Chair 1998 – 2002 Brian J. Scanlon, Chair 2002 – Theodore Ake, LC Craig R. Bertolett, Sr.** Norman R Bottom, Ph.D., CPP, CPO David Crawford, Ph.D., FIES Robert Daniels David Dean L. Vern Foreman John G. Hayes, Ph.D., CPP James Homins Gary Hovater Fred D. Justice Robert E. Kaeser Hyman Kaplan, L.C., P.E. Lorence E. Leetzow* Robert Lovelace Douglas W. Paulin Jeffrey Roche Mike Ross David L. Salmon, II C. Stanley Stubbe* David Stymiest P.E., SASHE, CEM * C. S. Thomas Timothy J. Walsh, CPP * Advisory ** Honorary Sub-Committee – Relationship Between Lighting and Crime David L. Salmon, II, Chair Norman Bottom, Ph.D., CPP, CPO Robert E. Kaeser David L. Salmon, Ph.D., CPO Brian J. Scanlon Editing Task Group Theodore Ake, LC, Chair Peter Boyce Douglas W. Paulin Brian J. Scanlon IESNA G-1-03 Table of Contents Foreword and History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Lighting and its Relationship to Crime. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2.0 Scope and Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3.0 Basic Principles of Security and Security Lighting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.1 Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3.2 Community Responsive Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.3 Security Lighting Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4.0 Understanding “When Security is an Issue” . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 5.0 Visibility Concerns in Security Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5.1 Illuminance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5.2 Horizontal Illuminance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.3 Vertical Illuminance. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.4 Uniformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.5 Glare. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.6 Shadows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.7 Establishing Site Divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.8 Total Site Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.9 Pedestrian Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.10 Pedestrian Path Zone. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.11 Building Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 5.12 Building Perimeter Zone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 6.0 Lighting Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 7.0 Security Lighting for Controlled Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 7.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 7.2 Specific Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 7.2.1 Unoccupied Spaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 7.2.2 Offices and Other Buildings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 7.2.3 Automated Teller Machines and Night Depositories . . . . . . . . . . . . . . . . . . . . . . . . . . 25 7.2.4 Parking Facilities (Lots and Garages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 7.2.5 Residential Parking Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 7.2.6 Parking Lots and Areas for Public Parks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 7.2.7 Supermarkets and Major Retail Outlets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 7.2.8 Fast Food and Franchise Restaurants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 7.2.9 Convenience Stores and Gas Stations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 7.2.10 Single-Family Residences. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 7.2.11 Multi-Family Residences and Dormitories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 7.2.12 Multi-Family Residences for the Elderly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 7.2.13 Schools & Institutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 7.2.14 Law Enforcement, Fire, Ambulance, and Other Emergency Services . . . . . . . . . . . . . 34 7.2.15 Hotels and Motels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 IESNA G-1-03 8.0 Glossary of Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Annexes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Annex A-Studies on Lighting and its Relationship to Crime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Annex B-Physical Security Survey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Annex C-Taking Security Illumination Measurements—A Practical Guide . . . . . . . . . . . . . . . . . . . . . . 44 Annex D-Crime Analysis and Foreseeability of Crime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Annex E-Crime Prevention Through Environmental Design [CPTED] . . . . . . . . . . . . . . . . . . . . . . . . . 52 Annex F-Lighting for Television and Photographic Surveillance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Annex G-Municipal Approvals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Annex H-Additional Reading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 IESNA G-1-03 IESNA G-1 Security Lighting for People, Property, developed material that was the basis for Chapter 2 and Public Spaces 29 of the IESNA Lighting Handbook, Ninth Edition. Foreword and History • During 1999, members of the Security Lighting Committee outlined the contents and approach for During World War I, the U.S. Government recognized a guideline for peer review and comment before the need for industry to increase exterior lighting at several professional groups. These groups includ- key production facilities, docks, assembly yards, high ed the American Society of Safety Engineers, and security facilities, and railway yards. These improve- the American Society for Industrial Security. ments had two purposes, to aid in production, and to deter sabotage. Although exterior protective lighting • During 2000, additional presentations were made was widely increased, no standard was set. before professional security groups concerned with the safety and security of the public, including the • With the advent of World War II, at the request of International Conference on Shopping Centers and the War Department, Military Intelligence, with the American Society of Industrial Security. assistance from the Insurance Committee for the Protection of American Industrial Plants, and the American Standards Association (ASA), initiated a 1.0 INTRODUCTION project to develop a standard on outdoor protective lighting for industrial properties. The primary pur- pose of these efforts was to prevent theft and sab- The Security Lighting Committee, previously known otage. Additionally, it was soon realized that “light as The Protective Lighting Committee of the discipline” was important to the war effort. Coastal Illuminating Engineering Society of North America facilities were darkened, and stray light was strictly (IESNA), was established to generate and develop controlled. North America was learning the impor- criteria for lighting to enhance the security of people tance of good security lighting and lighting disci- and property, to recommend the integration and inter- pline. action of lighting as part of a total security system, and to write a publication. • During 1942, the ASA War Standards Procedure was applied, and a War Standards Committee pre- 1.1 Lighting and its Relationship to Crime pared and published American Standard, A85- 1942, Protective Lighting for Industrial Properties. The possibility that lighting might have an impact on This eventually became an ANSI Standard. the incidence of crime was a topic of interest in the United States in the sixties. Municipalities across • In 1948, the ASA Safety Code Correlating America improved their street lighting to combat crime Committee terminated War Standards and institut- and some encouraging results were reported, but on ed a revised standard for peacetime use. The review there was no significant statistical evidence that Illuminating Engineering Society was designated improved street lighting influenced the level of street Administrative Sponsor for this effort. crime. There was, however, an indication that the improved street lighting decreased the fear of crime. • The IES Protective Lighting Committee developed the first draft of this revision, which the Sectional Twenty years later, in 1988, a before and after relight- Committee used as a basis for an American ing study of a street in the outer city area of London, National Standard Practice. England, by K. Painter demonstrated a marked reduc- tion in the incidence of crime and the fear of crime on • In 1977, The Protective Lighting Committee, IES, the relighted street. (See Annex A.) sponsored, wrote, and published American National Standard Practice for Protective Lighting- This lead to an outburst of similar studies in the UK by RP-10. This standard was intended as a guide for Painter (1989, 1991, 1994), Barr and Lawes (1991), outdoor protective lighting to those responsible for Burden and Murphey (1991), Davidson and Goodey 1 plant protection. (1991), Herbert and More (1991), Glasgow Crime Team (1992, Nair (1993), Ditton and Nair (1994) and • In 1994, a Security Lighting Committee was formed Cridland (1995). The results were mixed. by the IESNA. Its first project was to write a mod- ern guideline for security lighting for North America. The most sophisticated study undertaken on the effect of lighting on the incidence of crime was in 1999 in • During 1997-1998, the Security Lighting Committee Stoke-on-Trent in England by Painter and Farrington. 1 IESNA G-1-03 Three areas of housing were selected; one was the the use of property owners and managers, crime pre- experimental area where the lighting was improved; vention specialists, law enforcement and security pro- one was designated the adjacent area; the third was fessionals, risk managers, lighting specifiers, contrac- the control area, which served as the baseline against tors, the legal profession, and homeowners who are which any changes in crime could be monitored. The concerned about security and the prevention of crime. lighting in the adjacent and control areas remained Crime, its prevention, and the application of lighting to unchanged. One aspect of the study was to see if help minimize criminal activity, are considered in a less improved lighting in one area might lead to similar ben- technical and user-friendly manner for the benefit of efits of crime reduction in the adjacent area. There was property owners, but illuminating engineers, architects a marked reduction in the prevalence of crimes such and other professionals should find the concepts useful as theft and vandalism, vehicle crime, and personal to review with their clients. crime in the experimental area after relighting. There was no significant change in the adjacent or control The primary measurement references throughout this areas. A similar study in the town of Dudley, England, document are metric, with the English equivalent in showed that the level of delinquency decreased more parenthesis. For example, 1.5 meters will be dis- in the relighted area than in the control area. played as 1.5 m (5 ft), and 100 lux will be displayed as 100 lux (10 fc). These conversions are approximate, The results of all these studies indicate that lighting has but considered sufficiently accurate in this context. a place to play in crime prevention. A list of sources for further reading may be found in Annex A. While there In this publication will be found a discussion of basic are no guarantees that improved lighting will cause a security principles, illuminance requirements for vari- decrease in crime, there are circumstances in which ous types of properties, a protocol for evaluating cur- lighting can be an effective crime countermeasure, rent lighting levels for different security applications, either alone or in combination with other measures. and security survey and crime search methodology. The guidelines are based on consensus among mem- Lighting can affect crime by two indirect mecha- bers of the IESNA Security Lighting committee and nisms. The first is the obvious one of facilitating other security experts. surveillance by the authorities and the community after dark. If such increased surveillance is per- Suggestions are given for exterior and interior securi- ceived by criminals as increasing the effort and ty lighting practices for the reasonable protection of risk and decreasing the reward for a criminal activ- persons and property. This document also promotes ity, then the level of crime is likely to be reduced. a concept of best practice, which takes into account Where increased surveillance is perceived by the the following lighting design issues: criminally inclined not to matter, then better light- ing will not be effective.The second mechanism by • Economics (including cost, maintenance and oper- which an investment in better lighting might affect ational costs) the level of crime is by enhancing community con- • Environmental issues (including light pollution, light fidence and hence increasing the degree of infor- trespass and the adverse effects of light on animals mal social control. This mechanism can be effec- and plants) tive both day and night but is subject to many • Municipal lighting ordinances, by-laws or codes influences other than lighting. • Energy conservation, and maintenance requirements Minimum guidelines for the safe movement of per- 2.0 SCOPE AND PURPOSE sons and equipment and for performing specific tasks can be found in other IESNA publications. This docu- ment is intended to provide specific guidelines where The primary purpose of this publication is to establish it has been determined that security is an issue, and guidelines for the design and implementation of securi- where security is an important determining factor in ty lighting.* It addresses security illumination but does the design or retrofit of a given property. not give advice on construction practices. The objective is to provide guidance for designing security lighting Note that throughout this guideline the phrase systems for new facilities and for evaluating existing when security is an issue is used to differentiate facilities and systems. This publication is intended for the lighting design suggestions presented herein from those contained in other IESNA publications. * Note the distinction made in this document between security lighting and lighting for While these other publications may make refer- safety. Security lighting is intended to protect people and property from criminal activities. ence to security, in G-1 it is the only issue. Note too Lighting for safety is intended to provide safe working conditions, safe passage and iden- tification of hazards or obstructions. that when security is an issue, not only lighting, 2 IESNA G-1-03 but all measures and system components are potential perpetrators. Security works to deny oppor- increased and/or strengthened; for example, per- tunity, and increase the level of means or resources sonnel, surveillance, gates, locks, and fences. necessary for the criminal to successfully attack the target, and escape. When opportunity is limited, and a Security lighting, as part of a well-balanced security large amount of time and resources are required to plan, should have the following objectives: successfully complete a criminal act and escape, criminal motivation declines. 1. Provide a clear view of an area from a distance and enable anyone moving in or immediately Time - Time is the criminal’s enemy. The longer a around it to be easily seen criminal act takes in planning, execution, and escape, 2. Deny potential hiding spaces adjacent to fre- the more likely the crime will be deterred. Most com- quently traveled foot routes mon criminals will choose a property that requires the 3. Permit facial identification at distance of at least least amount of stealth, equipment, and planning. 9 m (30 ft), and create the perception of being identifiable Target hardening - A target is harder to attack when 4. Facilitate the proper use of other security coordinated security elements are provided. In the devices available on the property process of target hardening, deterrent objectives are 5. Deter crime against persons or property set, options reviewed, and steps taken to improve 6. Enhance the public’s feeling of comfort in security. The target is the people or property to be pro- accessing spaces and increase night-time tected, and the various security features are the hard- pedestrian traffic ening elements. Each separate security element adds to the others, making the target harder to attack. Security elements available to the professional will vary 3.0 BASIC PRINCIPLES OF SECURITY AND by situation, but often include management controls, SECURITY LIGHTING perimeter protection, a means of surveillance, response capabilities, and security lighting. A good security plan will contain layers of security features, and 3.1 Principles will not rely on one single security feature for success. Security lighting is installed to help protect people and property from criminal activities, and to create a per- Fight or flight - The basic decision made by persons ception of security. To better understand the principles when threatened is fight or flight. In other words…is of security lighting, it is first appropriate to look at sev- defense or evasion the appropriate measure? eral key security tenets. Sometimes, the act of fleeing danger is simply not an option due to circumstances. Fight may be the physi- Responsibility - In North America, the burden of secu- cal act of defense or a call for help. For police or secu- rity and safety is generally placed on the individuals rity officers, it usually means some form of physical who have primary control over a given property. With defense for serious threats. Flight, on the other hand, the rights of control comes the responsibility of con- may mean moving to a safe place, or getting out of the trol. For example, a property owner can enforce rules way of a presumed threat. Lighting, if properly of trespass, install security systems, restrict access, installed and maintained, can play an important role in and make other decisions that may have far reaching helping people make this basic decision. consequences for those who access the property. To a lesser degree, a tenant of the property may share in Security elements - Security elements can be active or this control and responsibility for the sublet space. passive deterrents. Active elements have the capacity to Owners and operators have or should have, a superi- interact with persons or generate a response to a crimi- or knowledge of the site’s history, including crime. nal’s actions. Passive elements include those security Casual visitors, invitees, or customers generally have features and applications that are static in nature and do no responsibility for security at a given site since they not interact with a would-be intruder or criminal. are not able to exercise reasonable control over the events at the location, or influence the environment. It Passive elements for a home or business may include is generally the responsibility of a resident, business deterrent features such as perimeter fencing or walls, operator, or property owner to provide for the safety open or barrier landscaping, exterior and interior illumi- and protection of human life and the property. nation systems, safes, open areas, and warning signs. Anticipating the threat - A helpful approach in deter- The most active deterrent is a patrol officer. The effec- mining the security needs of a property or operation is tiveness and response of uniformed individuals mak- to study the opportunity, means, and motivation of ing patrol rounds is often hard to predict, causing a 3 IESNA G-1-03 would-be criminal to pause. Other active applications, write ordinances or bylaws controlling light trespass. in wide use, include: interactive alarm systems, card One method is based on using specific Environmental or coded entry devices, metal detectors, security and Zone descriptions that underlie any restrictions on police officers, and trained animals such as dogs and outdoor lighting. Areas may be classified into a series geese. Some elements may be classified as both of Environmental Zones (E1 through E4) based upon active and passive deterrents. For example, moni- the extent to which control of light trespass is consid- tored closed-circuit television (CCTV), where there is ered necessary or desirable. These have been devel- a response or interactive capability is active, whereas oped by the International Commission on Illumination CCTV that is not monitored is passive. (CIE) and have been accepted by IESNA as suitable for application in North America. The Zones are Illumination as a key element in security design - defined by CIE as follows: Security lighting is usually passive in application. Exceptions to this general rule include luminaires that E1 Areas with intrinsically dark landscapes. Examples are automatically turned on and off by electronic are national parks, areas of outstanding natural motion sensors. By applying both passive and active beauty, or residential areas where inhabitants elements to some security lighting applications, the have expressed a strong desire for strict limitation designer can create uncertainty in the mind of the of light trespass. would-be criminal about being detected and observed. E2 Areas of low ambient brightness. These may be suburban and rural residential areas. Roadways The principles of security lighting applicable to new may be lighted to typical residential standards. facilities, or existing facilities, those being upgraded, E3 Areas of medium ambient brightness. These will or converted, include: generally be urban residential areas. Roadway lighting will normally be to traffic route standards. • Integration of illumination into the total security sys- E4 Areas of high ambient brightness. Normally this tem, thereby facilitating the effectiveness of other category will include dense urban areas with security devices or procedures; mixed residential and commercial use with a high • Illumination of objects, people, and places to allow level of nighttime activity. observation and identification, thereby reducing criminal concealment; Within any category a curfew of “after hours” time may • Illumination to deter criminal acts by increasing fear be established, allowing higher lighting levels during of detection, identification, and apprehension; those hours when the curfew is not in effect. • Lessening the fear of crime by enhancing a per- ception of security; There is no single set of values/limits that will work in • Illumination that allows persons to more easily every situation. The following recommendations3 ** are avoid threats, and to take defensive action when suggested illuminance limits to control light trespass. threats are perceived. The values for the various zones are measured at a very specific location-at the property line on adjacent 3.2 Community Responsive Design property and at the eye in a plane perpendicular to the line of sight. Illuminance values for security lighting Community responsive design applies to all exterior needs in Section 7.0 are measured in different planes lighting, regardless of its purpose (security, safety, and viewing angles and are not incompatible with the aesthetics). Security lighting should be evaluated for light trespass limits when issues such as glare and its appropriateness in the context of the overall envi- control of light distribution are addressed. ronment and surrounding community. Lighting for Zone and Recommended Maximum commercial, residential and transition areas in an Description Illuminance urban setting may have very different requirements Zone E1 1 lux (0.1 fc) (lighting levels and luminance ratios) than lighting in a Intrinsically dark rural or remote location where glare and light trespass Zone E2 3 lux (0.3 fc) issues may have increased importance. Low ambient brightness Zone E3 8 lux (0.8 fc) Light trespass usually fits into one of two categories: Medium ambient brightness Zone E4 15 lux (1.5 fc) • Adjacent property receives unwanted light (high High ambient brightness illuminance levels) • Excessive brightness occurs in the normal field of ** These recommendations are based on those in the “Guide on the Limitation of the vision (nuisance glare) Effects of Obtrusive Light from Outdoor Lighting Installations.” Report of CIE committee Efforts have been made in numerous jurisdictions to TC5.12 - Obtrusive Light. Commission Internationale de l’Eclairage, CIE, Vienna, Austria 4