Security Lighting

Security lighting can consist of internal or external systems, such as timer controlled interior lights, to give the impression that the premises is occupied. This system is not so effective during the hours of darkness as a house with the curtains open can be seen to be unoccupied.

External lighting can be by fixed floodlighting, PIR operated floodlighting and DUSK TO DAWN lighting.

Continuous flood lighting can be effective for isolated, large detached properties, but is less suitable for smaller domestic premises, sirtuated in built-up areas.

PIR operated 150 to 300 Watt floodlights are also popular, but the glare from them can disturb neighbours, especially on a windy night when they can operate almost continuously! OWLS AND FOXES AS WELL AS CATS CAN OPERATE PIR FLOODLIGHTS. The price of units varies considerably.

Always ensure that the units can be isolated from the mains supply and are accessible to enable maintenance to be carried out safely. The units are fitted with a photocell to stop operations during daylight hours. This may give the impression that the unit is not live during the day. If you are working on a light your shadow could fool the sensor into thinking that it is night time, and your movement will trigger the mains supply with disastrous results for you if you are touching live terminals!

More sophisticated PIR operated lights can be switched on permanently to continuously illuminate the exterior for late night gardening, parties etc. and most have a WALK TEST facility to allow the operation of the detection head and light during daylight hours. An internal sounder is also sometimes available - but ensure that it can be disabled in the event of a windy night etc. The sensitivity of the photocell and the switch on time duration can also be adjusted.

The replacement of Halogen strip bulbs must also be considered. A ladder will be necessary. A partial solution to floodlighting problems is to use Sodium lamps. These give a yellow tinted light and take a minute or to two obtain maximum brightness. The advantage of Sodium lights is their much lower power consumption, and much longer life, especially when fitted to permanent exterior floodlighting.

The downside of sodium lamps is the lack of contrast the light gives. Very little colour recognition is available.(SEE LINK AT END OF PAGE)

Dusk to Dawn lights (sometimes descrbed wroingly as dawn to duisk lighting!)--are photocell operated, and are usually fitted with highly energy efficient bulbs. They only operate at night, keeping the exterior in continuos light and automatically adjusting their operating times to the amount of daylight they are exposed to, through out the year.

They keep a subdued light on the exterior of the premises and need little maintenance. Most Crime Prevention officers favour this type of light. For more detailed information check with your local Crime Prevention Officer.

MORE INFORMATION - WELL WORTH LOOKING AT

http://en.wikipedia.org/wiki/Security_lighting#Planning_considerations