Crime Prevention Through Environmental Design, or CPTED, is a method used in security planning that focuses on design, placement and the way the building is used as a means to increase security in an aesthetically pleasing manner.
“CPTED tends to provide a purposeful sense of orderliness in developing a security program,” says William Nesbitt, president of SMSI. “It’s geared at trying to not only have an effective security program, but to have that program be perceived as being effective. It has to do with both the appearance and the perception.”
CPTED principles can vary from place to place and firm to firm, but the three that are fairly standard are Natural Surveillance, Natural Access Control, and Territorial Reinforcement. These principles, though most easily used when designing a new building, can be used in virtually any type of building or scenario, new or existing.
“Doing a lighting study is one of the most important pieces of the Natural Surveillance principle,” says Toby Heath, electromechanical specialist at ASSA ABBLOY. “That involves measuring the light output every 10 feet throughout parking lots and the perimeter of a building.”
Because light starts degrading as soon as you install a light bulb, chances are good that existing lighting isn’t particularly safe if it has been around for a while, says Heath. “One of the biggest things that people don't understand is that you have to look at light uniformity, which is the difference between the lightest and the darkest spot. You want to have certain thresholds so that when people are driving by or people are in the building, they can actually see what's happening.”
The 3-7 rule is an important component of natural surveillance as well, says Heath. This means that all landscaping around the perimeter of the facility should be no taller than three feet for shrubs and plants and there should be no foliage below seven feet for trees. This leaves a clear view of people, making criminal activity easier to spot. Heath says not following the 3-7 rule is a common oversight at facilities because people don’t realize that landscaping obstructions may cause points of vulnerability.
“The idea of surveillance in and of itself has a deterrent value,” says Nesbitt. For example, having parking lots adjacent to a building with no obstruction to the view no matter what floor you’re on may cause criminals to pause. For schools, putting the bike rack near classroom windows where it can be seen deters thieves, Nesbitt says.
Making sure windows are unobstructed and clear is another component, particularly in a public space, says Heath. “K-12 schools are a big violator because teachers like to put artwork up on the windows,” he says. “You need two-way visibility so people can look in and you can look out.”
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