Lighting for Safety and Security

Lighting system design is beyond the scope of this Web site. However, facility managers and others responsible for safety and security need to understand the principles of lighting to work more effectively with a professional lighting designer.

Two basic systems or a combination of both systems can provide practical and effective security lighting. The first method is to light the boundaries and approaches; the second is to light the area and structures within the property's general boundaries. Security lighting should:

• Discourage or deter attempts at entry by intruders. Proper illumination may lead a potential intruder to believe detection is inevitable.
  
  
• Make detection likely if an intruder attempts to enter.
  
  
• Prevent glare that may temporarily blind employees and security responders, keeping them from seeing an intruder.

Optimum security lighting is achieved by adequate, even light along the property’s borders, glaring lights in the eyes of an intruder, and little light on employees. In other words, provide employees with enough lighting so they can move comfortably, but direct glaring light into the eyes of an intruder, attacker, or person gathering intelligence.

High contrast between the brightness of an intruder and the background should be the first consideration when planning for security lighting. If surfaces are predominantly dark or dirty, more light is needed to produce the same brightness around buildings than when the surfaces are predominantly clean concrete, light brick, and grass. When the same amount of light falls on an object and its background, an observer must depend on contrast in the amount of light reflected. An observer’s ability to distinguish poor contrast is significantly improved by increasing the illumination.

When the intruder is darker than the background, the employee or security responder primarily sees an outline or a silhouette. Light finishes on the lower parts of buildings and structures may expose an intruder who depends on dark clothing and darkened face and hands. Stripes on walls also have been used effectively. They provide recognizable breaks in outlines or silhouettes. Providing areas of broad lighting around and within the installation also can create good conditions for observation.