5.2 Security Principles

This section provides some fundamental security concepts that place physical security into the context of overall facility security. The components of security include deception, intelligence, operational protection, and structural hardening. These components are interrelated (see Figure 5-1).

Ideally, a potential terrorist attack is prevented or pre-empted through intelligence measures. If the attack does occur, physical security measures combine with operational forces (e.g., surveillance, guards, and sensors) to provide layers of defense that delay and/or thwart the attack. Deception may be used to make the facility appear to be a more protected or lower-risk facility than it actually is, thereby making it appear to be a less attractive target. Deception can also be used to misdirect the attacker to a portion of the facility that is non-critical. As a last resort, structural hardening is provided to save lives and facilitate evacuation and rescue by preventing building collapse and limiting flying debris.

Because of the interrelationship between physical and operational security measures, it is imperative for the owner and security professional to define early in the design process what extent of operational security is planned for various threat levels.

If properly implemented, physical security measures will contribute toward the goals listed below in prioritized order.

• Preventing an attack. By making it more difficult to implement some of the more obvious attack scenarios (such as a parked car in the street) or making the target appear to be of low value in terms of the amount of sensation that would be generated if it were attacked, the would-be attacker may become discouraged from targeting the building. On the other hand, it may not be advantageous to make the facility too obviously protected or not protected, for this may have the opposite of the intended affect and provide an incentive to attack the building.
• Delaying the attack. If an attack is initiated, properly designed landscape or architectural features can delay its execution by making it more difficult for the attacker to reach the intended target. This will give the security forces and authorities time to mobilize and possibly to stop the attack before it is executed. This is done by creating a buffer zone between the publicly accessible areas and the vital areas of the facility by means of an obstacle course, a serpentine path and/or a division of functions within the facility. Alternatively, through effective design, the attacker could be enticed to a non-critical part of the facility, thereby delaying the attack.
• Mitigating the effects of the attack. If these precautions are implemented and the attack still takes place, then structural protection efforts will serve to control the extent and consequences of damage. In the context of the overall security provided to the building, structural protection is a last resort that only becomes effective after all other efforts to stop the attack have failed. In the event of an attack, the benefits of enhancements to life-safety systems may be realized in lives saved.

An effective way to implement these goals is to create layers of security within the facility (see Figure 5-2). The outermost layer is the perimeter of the facility. Interior to this line is the approach zone to the facility, then the  building exterior, and finally the building interior. The interior of the building may be divided into successively more protected zones, starting with publicly accessible areas such as the lobby and retail space, to the more private areas of offices, and finally the vital functions such as the control room and emergency functions. The advantage of this approach is that once a line of protection is breached, the facility has not been completely compromised. Having multiple lines of defense provides redundancy to the security system, adding robustness to the design. Also, by using this approach, not all of the focus is on the outer layer of protection, which may lead to an unattractive, fortress-like appearance.