Perimeter Security: Selling Successful Outdoor Security

Project Specifics: Perimeter Protection Layers

Multi-layered detection is effective in catching criminals in the act of penetrating the outer perimeter of a complex while assuring that security only responds to valid targets. This is accomplished by utilizing multiple sensor technologies. The following is a brief description of a large campus equipped with multiple perimeter sensor technologies.

  “The building is covered by four layers of security starting outside the first fence line,” explained Louis Katona, president of VidCorp Security Systems Inc., Houston. “Buried, leaky cable is about 15 feet past the fence line which provides the first alert. High resolution night vision cameras with auto positions are tied to the sensor field to track intruder activity.”

Inside the first fence line is volumetric microwave links which overlap and provide a second sensor field. All sensor areas are also mapped inside the facility for easy identification of the breached area. Another leaky cable detection zone is between the inner and outer fence line. The entire sensor system is zoned since the fence line is over ¼-mile wide. Thermal imaging cameras are placed at strategic locations to cover the entire fence line.

 “The inside fence area is protected by fence line sensors that provide additional data to the system,” said Katona. “The interior fence perimeter is covered with active inferred wall of light beams. The beams provide a stable detection mode for penetration and tracking date to the interior surveillance system. The only vehicle entry point is a dual fence gate which is an interlock system that holds the vehicle inside for identification. The road inlet is protected by a barrier system to trap high speed approach. Sensors along the road track and alert the facility of approaching traffic.”

Katona said that the information is processed by three computer systems which are redundant and supported by alternative power in the event of a power outage. This layout is a typical facility layout and contains some other measures that can’t be discussed.

The D5 Strategy

Outdoor perimeter detection is the first line of defense in a large complex, whether it contains one, two or a dozen structures. Traditional security methodology relies almost entirely on physical barriers to deter and delay, but that alone is not enough to assure a secure environment. This is especially true when a complex is rated as medium- to high-risk. But electronic detection alone is inadequate unless it is accompanied by sufficient physical barriers.

“Early detection of hostile intent and prevention cannot be counted upon to always work,” said Hagai Katz, senior vice president of Marketing and Business Development, Senstar, Ontario, Can. “Individual critical infrastructure facilities must therefore have the physical means to both detect and defeat attacks when everything else fails. In physical security, the perimeter is the first line of defense.”

Employing a combination of physical barriers and more than one layer of electronic detection assures that unauthorized individuals are detected and delayed until security personnel can mobilize and arrive on the scene.

Effective outdoor protection involves something called the D5 Strategy, Katz said. The five key components include: demarcation, deterrence, detection, delay and defeat.

“The first two D's are very basic—the perimeter should visibly be demarcated so that an intruder knows he is trespassing. Adding deterrence, be it by sharp edges or high barriers, discourages attack and makes determining hostile intent even easier, as intruders who make the effort to cross the barrier are more likely to be hostile,” Katz explained.

The remaining three D's assure that the target is detected and verified electronically as quickly as possible. Once detected, a well-engineered outdoor perimeter security program will seek to delay access to the facility itself, which gives security time to respond in an effort to defeat, or apprehend.

To make the five D's a reality, integration and coordination is required in an effort to detect intruders while assuring a low false and unwanted alarm rate.