Protective lighting is a smart addition to any security system. Using light to deter intruders is cheaper and more effective than you think.

With so many methods and strategies available to keep trouble away from your facility, it would seem you could achieve freedom from theft and vandalism. Although it may not be entirely possible, the ultimate goal of planning and security measures is to keep bad things from happening. Let's take a look at how protective lighting can help keep intruders away.

Security lighting. You should design protective or security lighting systems on a facility-by-facility basis. There isn't a one-size-fits-all approach. Each situation requires careful study to provide the best visibility for security duties, such as identification of badges and people at gates, inspection of vehicles, prevention of illegal entry, and detection of intruders (outside and inside building structures).

You should not use protective lighting as a psychological deterrent only. Use it at a perimeter fence, but only where the fence is under continuous or periodic observation. Protective lighting may be unnecessary where a central alarm system is in place.

Security lighting is relatively inexpensive to maintain and, when properly employed, it may reduce the need for security. It may also provide personal protection for occupants by reducing the advantages of concealment and surprise from an intruder.

Protective lighting usually requires less intensity than working light, except for identification and inspection at authorized portals and in emergencies. Each area of an installation presents a problem based on physical layout, terrain, and climatic conditions.

Design issues. Consider two key components when designing a security lighting system: security effectiveness and operational efficiency.

In general, it's best to first design for security effectiveness; finding the best methods of lighting your facility for safety. Then, design the system for practical operation. Don't worry if you have to give up a little on the second "run-through," because having a system that's reliable and easy to operate is very important. Overly complex systems tend to breakdown and malfunction too often.

Principles of protective lighting. Protective lighting should enable security personnel to observe activities at an installation without disclosing their presence. Adequate lighting for all approaches to an installation discourages attempted unauthorized entry and reveals persons in the area. However, don't solely rely on lighting. You should use it with other measures, such as fixed security posts or patrols, fences, and alarms. Your goal is to place glaring lights in the eyes of the intruder and relatively little light on security patrol routes.

When planning protective lighting, a high brightness contrast between the intruder and background should be your first consideration. With predominantly dark dirty surfaces or painted surfaces, you'll need more light to produce the same brightness around installations and buildings than when clean concrete, light brick, and grass predominate. When the same amount of light falls on an object and its background, the observer must depend on contrasts in the amount of light reflected.

You can foil intruders who depend on dark clothing by using light finishes on lower parts of outdoor structures. Stripes on walls provide recognizable breaks in outlines or silhouettes. For effective protective lighting, light the boundaries and approaches as well as the area and structures within the property.

Types of lighting. Choosing the best type of lighting system depends on the overall security requirements of the installation. Let's look at four types of lighting units that provide protective lighting.

• Continuous lighting (stationary luminary). This is the most common protective lighting system. It consists of a series of fixed luminaries arranged to flood a given area continuously during the hours of darkness with overlapping cones of light.

• Standby lighting (stationary luminary). The layout of this system is similar to continuous lighting. However, you set the luminaries to automatically or manually turn on only when the security force or alarm systems recognize suspicious activity.

• Movable lighting (stationary or portable). This type of system consists of manually operated movable searchlights. You would normally use this system to supplement continuous or standby lighting.

• Emergency lighting. This system may duplicate any or all of the above systems. Its use is limited to times of power failure or other emergencies. It depends on an alternative power source, such as installed or portable generators, or batteries.

Lighting levels. You should illuminate open yards (unoccupied land only) and outdoor storage spaces (material storage areas, railroad sidings, motor pools, and parking areas) as follows:

• Illuminate an open yard adjacent to a perimeter (between guards and fences) in accordance with the illumination requirements of the perimeter. Where lighting is necessary in other open yards, illumination should not be less than 0.2 footcandles (fc) at any point.

• Place lighting units in outdoor storage spaces to provide an adequate distribution of light in aisles, passageways, and recesses; to eliminate shadowed areas where unauthorized persons may hide.

• Safeguard piers and decks by illuminating the water approaches and pier area. Illuminate decks on open piers to at least 1.0 fc and water approaches (extending to a distance of 100 ft from the pier) to at least 0.5 fc. Light the area beneath the pier floor with small wattage floodlights. Experts recommend movable lighting with direction capabilities for these areas. Contact the U.S. Coast Guard for approval of protective lighting adjacent to navigable waters.

• When designing protective fencing and lighting, first consider critical structures and areas. Power, heat, water, communications, explosive materials, critical materials, delicate machinery, and areas containing highly classified material and valuable finished products need special attention. Make sure you light the surroundings to a height of 8 ft to facilitate silhouette vision and force an intruder to cross the lighted area.

Lighting in exclusion areas. All exclusion areas (areas for authorized personnel only) must have protective lighting on a permanent basis at perimeter and access control points. The lighting must:

• Prevent glare that temporarily blinds guards,

• Avoid silhouetting or highlighting the guards,

• Yield to the control of the security force,

• Provide a minimum intensity of 0.2 fc at the perimeter band, measured horizontally 6 in. (15.2 cm) above ground level, at least 30 ft (9.1 m) outside the exclusion area barrier. Lighting at entrance control points must allow guards to compare and identify bearers and badges,

• Operate during all hours of darkness, and

• Guarantee the failure of one or more lights will not affect the operation of remaining lights.

As you can see, protective lighting is key to the success of any security system but so is "seeing them coming." Next month, we'll discuss how video monitoring, remote sensing, and threat assessment can help you further protect personnel.