Every security program must be an integrated whole and each element must grow out of the specific needs dictated by the circumstances affecting the facility to be protected. Nevertheless, the first and basic defense is still the outer perimeter of the facility. Planning this defense is neither difficult nor complicated, but it is the product of common sense. Whereas the engineering and design of an electronic security management system requires particular sophistication and expertise, the implementation of an effective physical security program is the result of conventional wisdom and a lot of legwork expended during a security assessment.
A basic security concept is to design a series of layers so that highly protected assets are within a configuration of multiple barriers. Barriers are commonly utilized to discourage three types of penetration – accidental, by force, and by stealth. A properly installed barrier should clearly warn a potential penetrator to “Keep Out”. There should be no accidental or inadvertent penetration.
Barriers may be divided into two general categories – natural and structural. Natural barriers include terrain difficult to traverse and other topographical features that assist in impeding or denying access to an area. Structural barriers are manmade and include landscaping, ditches, fences, and walls. A structural barrier physically and psychologically deters or discourages the undetermined, delays the determined, and channels the flow of authorized traffic through proper entrances.
The most common type of structural barrier normally used for protection is a chain link fence. Fencing an area will only delay, not permanently prevent, an entry attempt. Therefore, fencing must be supplemented or enhanced by other countermeasures such as signage and security patrols. Nevertheless, a fence can be a valuable element in an integrated protection scheme.
Any barrier utilized must be supplemented or enhanced by other countermeasures such as signage. In keeping with this philosophy to be a “good neighbor” and have an open campus environment for lawful and undisruptive use, a signage program to clearly define the expectations of the administration should be deployed. Two categories of signs, the command sign and the informational sign, are predominantly used. Command signs tell people what to do or not to do. Examples are “No Trespassing”, “No Admittance”, and “Visitors must register at the front office.” Informational signs may alert the reader to a potential danger or give other information. Examples are “Hazardous Materials” and “No Smoking”.
Vegetation and Crime Prevention Through Environmental Design (CPTED)
In security applications the concept of Crime Prevention through Environmental Design is one that is prominently used. The concept emphasizes that lighting, vegetation management, traffic flow, pedestrian flow, and other physical attributes can be manipulated to lessen the opportunity of a crime-related event occurring in a particular location.
Security industry standards suggest that foliage be trimmed to allow for casual surveillance. Tree limbs should be trimmed seven feet from the ground and shrubbery trimmed to 24 inches high.
Another layer of security continues with building access control. An excellent tool to control access requires the determination, not less than annually, of the minimum number of exterior doors that should be unlocked at any given time. Whenever possible, it should be the policy to manage access by utilizing only those exterior doors that are practical and/or absolutely necessary to the day-to-day operation.