Excessive Lighting Does Not Improve Safety, Security
Unnecessary lighting is more costly, as well as environmentally unfriendly. Excessive lighting does not improve safety or security; the key is the right amount and type of lighting.
One type of waste is lighting kept on in the parking lot of an office building where everyone goes home at eight. "You can draw gates so that the property is closed or have actuated lights that come on when someone drives under a pole," says David Salmon, owner, OSS — Law Enforcement Advisors.
IESNA publications specify types of environments in relation to background lighting, on a scale from 0 to 4. For example, a wildlife zone would be rated 0, while a downtown urban area would be rated 4. "The limitations on uplighting and glare are more severe in darker environments and less severe in brighter environments," says Donald Monahan, vice president of Walker Parking Consultants. "Security-level lights are designed to discourage perpetrators from entering your facility," he says. For safety purposes, visibility increases as light increases, up to a certain point, and then visibility levels out. Too much light produces glare and wastes energy, Monahan notes.
Light trespass occurs when lighting is too horizontal, Aggleton says, and enters neighboring areas. "To cut the light off you have to shine it down, not horizontally, which is good for safety but not security," he says. One way to eliminate trespass is to turn lights off in the evening where there is very little or no traffic — pedestrian or vehicular. Security officers can be employed when a parking lot or other area has traffic at night and where safety and security are issues that cannot be well addressed with lighting.
Maryellen Lo Bosco is an Asheville, N.C.-based freelance writer who covers facility management and technology. She is a contributing editor for Building Operating Management.
New Technology Choices for Exterior Lighting
Traditionally, external lighting used metal halide or high-pressure sodium fixtures, but they are being replaced with LED and induction fixtures, says Donald Monahan of Walker Parking Consultants.
LED lighting has attracted a lot of interest from facility managers. Induction lighting is not as new as LED lighting, but it is newer than HID lighting. Both LED and induction lighting receiving a lot of attention because of their long life, says Monahan.
Longer service life is not the only advantage. Both LEDs and induction lighting are dimmable and provide instant restrike capability and better color rendering than older alternatives, says Lindsay Audin, president of Energywiz.
— Maryellen Lo Bosco