Feature Article - September 2007
Find a printable version here

Let There Be Dark

How Smart Lighting Design Increases Security, Performance and Night-Time Aesthetics

By Emily Tipping



Security Doesn't Always Mean More Light

Many of us consider lighting essential to a feeling of security at night. But that doesn't necessarily mean more light is better. What we want to ensure is that people actually are safe in our facilities—not just that they feel safe. And that means more than lighting up every single square inch of space inside and out.

In fact, according to the International Dark-Sky Association (IDA), most crime actually occurs during daylight hours or inside buildings.

"What we do need," the organization states, "is effective lighting, lighting that puts light where we need it (and nowhere else) and where it will help visibility. That means: no glare, no light trespass, no harsh shadows, no steep transitions from dark to light, etc."

Too much light can actually mess up our ability to adapt as we walk into areas that are less well-lit at night, according to the IDA, an effect called "transient adaptation." In addition, the extra light is often lost into the sky or is lost horizontally, rather than targeting the areas we actually need to see—the sidewalk, the doorway, etc.

Poor-quality security lighting may make people think they're safe, but in some cases, it can actually make people less safe. Examples cited by the IDA of poor-quality security lighting include 175-watt dusk-to-dawn security light fixtures and barnyard-style lights left on all night long; globes, which may look good in the daytime but produce a lot of glare, making it difficult to see the ground; poorly shielded "wall packs" and poorly designed flood lights.

Good-quality security lights put light where it is needed, reducing glare and helping patrons see what needs to be seen. Examples cited by the IDA of good-quality security lights include well-shielded low-pressure sodium fixtures or similar-cutoff high-pressure sodium or metal halide fixtures; well-controlled and smartly installed flood lights or spot lights; and infrared sensor spot lights that only come on when someone walks into the field of view of the sensor. Motion-controlled lights are smart because they provide good visibility when it's needed, but also can scare away the bad guys.

In addition to lighting, we can rely on other methods of increasing security, like security cameras or even dummy security cameras, and neighborhood watches.