What is Security Lighting
Security lighting can be used in residential, commercial, industrial, institutional, and
military settings. Some examples of security lighting include floodlights and low pressure sodium vapour lights. Most lights intended to be left on all night are high-intensity discharge lamps as these have good energy efficiency, thus reducing the cost of running a lamp for such long periods.
A disadvantage of low pressure sodium lamps is that the color is pure yellow, so the illuminated scene is seen without any color differentiation. Consequently high pressure sodium vapour lamps (which are still yellowish, but closer to golden white) are also used, at the cost of greater running expenses and increased light pollution. High pressure sodium lamps also take slightly longer to re-strike after a power interruption.
Other lights may be activated by sensors such as passive infrared sensors (PIRs), turning
on only when a person (or other mammal) approaches. PIR activated lamps will usually be incandescent bulbs so that they can activate instantly; energy saving is less important since they will not be on all the time. PIR sensor activation can increase both the deterrent effect (since the intruder knows that he has been detected) and the detection effect (since a person will be attracted to the sudden increase in light). Some PIR units can be set up to sound a chime as well as turn on the light. Most modern units have a photocell so that they only turn on when it is dark. There is also motion censors that activate when there is movement around the censor and will activate regardless of temperature.