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Watt's up with your security survey?


AS A SECURITY CONSULTANT, director, or manager you know protective lighting plays a critical role in any facility's security. Security lighting entails much more than placing a lighting fixture on top of a pole; many other factors must be considered. These include fences, walls, gates, doors, windows, and naturally made barriers to guard against theft or intrusion. When you are conducting a security survey to determine your facility's needs, lighting must be a paramount consideration.

In many instances, people do not consider lighting a useful tool in preventing and combating crime. Most facilities have inadequate or no exterior lighting and rely on streetlights to provide the only source of illumination. However, property owners can be held accountable if it is determined a person was injured or a victim of a crime due to inadequate lighting. As noted in Building Laws of the City of New York, the common-law theory of negligence states that "one who maintains a premise upon which another can be expected to enter is under an affirmative duty to make every reasonable effort to remedy conditions which could foreseeably create or contribute to a dangerous crime inducing hazard."

Security lighting

* illuminates any target of security interest,

* acts as a psychological barrier or deterrent against intrusion or criminal attack,

* provides people with a legitimate sense of security, and

* provides police and security officers with a better means of identifying or apprehending a criminal.

THE FOUR BASIC TYPES OF PERIMETER LIGHTING THAT enhance any security operation are continuous lighting, emergency lighting, movable or portable lighting, and supplemental or standby lighting.

Continuous lighting. This is probably the most widely used type of perimeter security lighting. It accomplishes two goals: to light boundaries of a facility as well as approaches to it and to focus light on a particular area.

Boundary areas are usually lit in correctional facilities but not in areas where glare will interfere with neighbors or traffic. This method of lighting prevents an intruder from seeing into the protected area, thereby creating a strong visual and psychological deterrent.

Emergency lighting. This form of security lighting is used in times of power failure or when a disaster makes your primary lighting system inoperable. This system uses an alternate power source such as a generator or battery.

Movable or portable lighting. This system is manually operated and uses movable or portable hardware such as floodlights, searchlights, and hand-held lights.

Supplemental or standby lighting. This system consists of a continuous lighting system but is usually designed for reserve or standby use to supplement your continuous lighting system. The system can be operated automatically or manually when your lighting system fails.

AS A SECURITY PROFESSIONAL CONducting a facility security survey, you must understand the language of lighting. The following definitions are widely used in the lighting field and will help you specify your needs to lighting specialists:

* lumen--a measure of light that emanates from a light source in all directions. A lumen is usually measured as in the number of lumens per watt in determining efficiency.

* watt--a measure of electrical power necessary to generate a certain amount of light. Watts are generally measured in the number of watts used per hour. This is usually the basis for charging for the use of electrical power.

* luminaire--a complete lighting device consisting of a light source together with its direct appurtenances, such as a globe, reflector, refractor, housing, and other support that is integral with the housing. The pole, post, and bracket are not considered part of the luminaire.

* footcandle--the amount of light that would shine on a surface one foot from the flame of the candle. Footcandles are usually measured by light meters.

* light source--any incandescent, fluorescent, mercury vapor, metal halide, high pressure sodium vapor, or low pressure sodium vapor light source.

When conducting your survey, consider the following cardinal rules for determining your security needs:

Rule #1. Never create unnecessary glare. While glare may be used as a deterrent, you must be careful not to annoy or offend neighbors, passing motorists, or pedestrians. In security applications where closed-circuit televisions are used, glare in the camera faceplate may render the camera useless at night. This may be avoided by using screens under the luminaires or, when using floodlights, by not aiming more than 45 [degrees] above a horizontal position.

Rule #2. Adhere to the "two and four times" rule of thumb. Light is projected two times its mounting height. Therefore, luminaires should not be spaced more than four times the mounting height from one another or two times the mounting height from the unlit area. Following this rule of thumb will allow for a more even distribution of light and prevent dark areas.

Rule #3. Provide the necessary illumination for the task. Size the luminaire properly to achieve the necessary illumination with respect to the proper mounting height. (Established minimum illumination levels for various areas are published by the Illuminating Engineering Society of North America.)

Rule #4. Choose the proper light source. Choosing the proper lamp type is paramount. Many factors are involved, such as lamp life, efficiency, color-rendering qualities, warm-up characteristics, size, and cost.

THE MOST SIGNIFICANT QUESTION on your mind when conducting your security lighting survey will be what type of light source is most effective and least expensive. This question can be answered after familiarizing yourself with the accompanying lighting comparison chart.

One term often used when determining effective yet inexpensive lighting is clustering. It is expensive to wire a lamp column or other hardware using a single luminaire. However, by clustering two or more luminaires on a single lamp column you can reduce cost. The more support poles you use, the more expensive the installation will be.

Lighting your target area properly is critical. You want lighting evenly spread. By improperly spacing light columns you will defeat the purpose to create a visual deterrent. For example, lights spaced too far apart give the area pools of light between pools of darkness, making your lighting ineffective.

In determining the cost-effectiveness of your proposed security lighting system, you must understand how light is purchased--how the utility sells power. Keep in mind that utilities vary their rates. Utilities also charge different rates for different seasons and for commercial and residential buildings. An analogy for lumens per watt is miles per gallon. More lumens per watt translates to lower operating cost and greater efficiency.

Protective lighting is crucial to your facility's security scheme and therefore your security survey. By including lighting security in your security survey and by questioning lighting engineers, local utility personnel, and other professionals, you will be able to safeguard your facility from potential problems on-site and in court.

Kevin A. Cassidy is director of safety and security for Homes for the Homeless in Jamaica, NY; Maurice Dipierro, CPP, is crime prevention specialist for Double M Security in Valley Stream, NY; Robert Brandes is a police officer and crime prevention division specialist for the New York City police department in Jamaica, NY; and Phillip Thomas is lighting consultant for Garden City Lighting Inc. in Garden City, NY.
COPYRIGHT 1989 American Society for Industrial Security
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1989 Gale, Cengage Learning. All rights reserved.

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Author:Cassidy, Kevin A.; Dipierro, Maurice; Brandes, Robert; Thomas, Phillip E.
Publication:Security Management
Date:Aug 1, 1989
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