Security starts with lighting. Don’t believe it? Think about this: A security concept called Crime Prevention Through Environmental Design (CPTED) teaches that appropriate lighting makes people who belong in a space feel comfortable and safe and trespassers uncomfortable. Combine visible cameras and appropriate CPTED lighting to send potential malefactors packing.
Security Lighting Principles
“Lighting exposes actions and deters criminals,” says Kevin T. Doss, MS, PSP, CPP, author of the Physical Security Professional Study Guide (2nd edition), for ASIS International’s PSP certification.
Doss’s PSP Study Guide identifies five keys for lighting security cameras:
1. Light to provide a high contrast between an intruder and the background. Lighting should enable a security officer or camera to clearly see an intruder’s clothing, face, and other identifying features.
2. Illuminate both sides of a building’s perimeter – just outside and just inside – to make intruders feel visible before crossing the perimeter.
3. Direct lights from inside out to create glare for intruders while providing clear views for patrolling officers and cameras.
4. Protect lighting systems from tampering with protective covers, elevated mounts, buried or protected power lines, and secured switchboxes.
5. Create redundant lighting systems for emergencies, such as power outages. Cover all paths of egress, including stairwells.
Kinds of Light
The color rendering capability of various types of lighting ranks as a key security consideration. To match lighting to security needs, consider these sources of lighting:
Natural light is the best light because it renders color clearly and accurately, making it possible to identify people and objects.
Incandescent lamps render color well, power up instantly, and cost relatively little. They don’t last long, however, and require 10-25 watts to produce a lumen, which is inefficient and expensive. Despite these drawbacks, security professionals favor incandescent lighting.
Halogen lamps, another security favorite, power up instantly and render color well. Halogen lamps are 25% more efficient than incandescent lamps.
Fluorescent lamps take a couple seconds to illuminate. They are twice as efficient as incandescent lamps, render color well, and last up to 15,000 hours. Drawbacks include poor performance in cold temperatures, which limits security lighting use to indoor areas.
LEDs have begun to appear in security applications. LEDs render color well and last up to 100,000 hours. Disadvantages include expensive fixtures and sensitivity to heat.
High-pressure sodium lamps produce 100 lumens per watt and last up to 28,000 hours. Likewise, low-pressure sodium lamps offer low costs and a long useful life. Both render color poorly and produce low-quality video. Security professionals tend to avoid these lights.
Test and Verify
“When lighting for security cameras, you must account for certain environmental conditions,” says Doss.
Lighting should illuminate scenes directly to manage light pollution, Doss explains. Backgrounds should reflect light – remember black and dark colors absorb light, while white and light colors reflect it.
Uniformity is also important. As a rule, a light-to-dark ratio of 4 to 1 or less will provide uniformly usable video.
Before buying, test cameras with light levels set to the minimum specifications. “Have your vendor demonstrate the cameras at night in your facility,” says Charles L. Butler, MPA, CPP, director of security programs in the Security Services Group of the Belleview, FL, offices of Gannett Fleming, an architectural and engineering consultant.
Test the areas you plan to monitor: exterior spaces, interior corridors and doorways, and parking structures and parking lots.
Testing is important for day-night cameras, which switch to black and white imaging at night because the color chip typically requires more ambient light than is available at night. Make sure the camera switches to black and white in various locations. If it doesn’t get sufficiently dark, the camera may fail to switch and the resulting color video may be useless. Check the black-and-white images too.
After testing, adjust the lighting to ensure the quality of the video or test a different camera, noting that you may run into difficulties.
Sometimes you can’t adjust the light. An interior camera trained on an exterior door, for instance, may see nothing but glare from the sun when the door opens in the morning. More expensive wide-dynamic-range cameras can minimize glare and function under varying light conditions.
Turn Off the Lights
Some buildings don’t need lighting 24/7. But if you turn the lights off, even the best conventional cameras won’t produce useable video.
“Don’t pay to keep the lights on all night,” says Butler. “Invest in good quality color day-night cameras with infrared (IR) illuminators. Get a lighting expert to help make sure the IR illuminators cover the space you want to monitor.”
Surfaces reflect IR light just like visible light, continues Butler. You can’t see the IR light, but the cameras can and the video will look fine.
Better yet, you can pay the higher camera price with the utility savings. Powering the IR lights will cost only about 20% of the cost of running the conventional lights.
Make sure to evaluate your security lighting to ensure your budget, people, and property are protected.