Security Lighting: a safety measure

Among the various techniques of crime prevention through environmental design, use of security lighting is the most widely used one. Security lighting is included under physical security, and is used as a preventive and corrective measure against intrusions, vandalism, or any other similar criminal activities which may affect any piece of property. The use of security lighting sometimes even helps by increasing the feeling of safety.

Contrary to popular perception, a brightly lit area does not necessarily mean reduced chances of criminal activities. In fact, studies conducted in various parts of the world have concluded that reducing the light led to a reduction in stealing and theft considerably. This can be attributed to the fact that a brightly lit area also provides the criminal with a good view of the surroundings and of what he is doing. Similarly, an extremely bright but poorly arranged light may create glare, which obstructs vision making it difficult to monitor the area from a distance, thus giving a cover to the criminals, especially because criminals are aware of such an effect and actively exploit it to their advantage. Thus security lighting conditions must be so arranged so as to provide the observers with an optimum field of vision, and to discourage intruders and criminals. Full cut-off housings used for security bulbs can be used to effectively shield the bulb’s light, so as to direct the light towards the target area, or away from the observers to cut off the glare. The intensity of lighting should not be made “as bright as possible”, but reduced to an optimum level. Multiple sources of light with moderate power are a much better option than a few sources of light with high intensity, as it provides even illumination and reduces pools of shadow, while also providing more reliability in case one of the sources becomes defective.

Security lights are also often subjected to vandalism by miscreants, which is why they should be placed high above the general reach, or properly protected. The circuits must be checked and service providers should be close by in order to repair any malfunctions. Power supply lines should be buried underground to prevent cases of arson.

Common examples of security lighting are floodlights and low pressure sodium lamps. The disadvantage with sodium lamps is that they emit pure yellow light, which reduces colour differentiation of the viewer. Recently, passive infrared sensors have also been used for security lighting.