How to Avoid Pitfalls With Outdoor Safety and Security Lighting
Outdoor safety and security lighting requires just as much attention as an illumination system inside a building. But exterior lighting brings a very different set of considerations to be addressed, issues that are often less familiar to the facility manager. The result is that facility managers sometimes overlook important considerations when planning for exterior lighting installations.
One big mistake is not conducting a risk assessment. This may seem obvious, but this step is often bypassed on the way to installing new outdoor lighting. Often facility managers add security features after a problem arises, explains David Salmon, law enforcement advisor for OSS — Law Enforcement Advisors, who is also a past chair of the security lighting committee for the Illuminating Engineering Society of North America (IESNA); he was chair in 2003 when the organization last published the G-1-03 guidelines. A facility should look at its vulnerabilities and apply reasonable and cost-effective measures to protect itself. Salmon notes that "85 percent of facilities have never had a risk assessment done."
For the purposes of risk assessment, it's important to know who the occupants of the building are and what their needs are, Salmon says. "If a tenant has after-hours activities, that will influence the lighting scheme," he says. "[Facility managers must] have enough lighting in the parking lot for hours that people are coming and going, especially unescorted females."
Too often facility managers focus on buying a certain number of fixtures, when it would be better to hire a lighting designer "to meet specifications of what they want on the ground and to ensure light uniformity," Salmon says. Correct lighting design will take into account local ordinances and guidelines as well as the light from surrounding businesses, Salmon says.
"Facility managers need to focus on high-efficiency lights that draw less energy but produce a high quality light with a broad color spectrum," says Salmon. Light waste and light trespass can be avoided by using lamp cutoffs, which shield lamps so they don't throw light off the property. Correct lamp design can also ensure that light is not unnecessarily thrown up into the sky to create sky glow.
One big mistake in design is not taking transitions into account. For example, says Salmon, a guard shack or an ATM machine may be lighted by 10 foot-candles, while the parking lot is lighted by three foot-candles, and the sidewalk that leads into the building gets one foot-candle. "You have to account for transition from one area to the next," he says. "You don't want to have abrupt changes of lighting, because the eye needs to refocus and utilize light." This is a safety issue, one that is especially relevant with an aging population. According to Salmon, elderly people require 60 percent more light to see than those in their 20s, and it's important for a facility to take this fact into consideration, especially if it caters to an older clientele.