appropriate to the assessed threat. In addition, the use of fencing to
enclose military installations or to enclose and separate areas within a
military installation should be limited to those conditions requiring
physical security or protection of life, except as stipulated for family
Establishing the Security System Design Threat
Overview. The "design threat" comprises the specific types of
attacks and their relative severity levels which could be directed at the
facility and assets during its life cycle. Based on historical patterns and
trends, the general categories, characteristics, and relative severity levels
of attacks shown in Table 1 have been compiled for use in this handbook.
Which of these apply to the facility being designed depends on the types of
hostile aggressors in the area of the facility and their objectives. The
following outlines the major factors one must consider in the selection of a
proper design threat.
Design Threat. A clear distinction must be maintained between what
is meant by a "design threat" (as shown in Table 1) and a threat "estimate."
As used here a design threat is inherently concerned with the broad range of
attack possibilities over the life cycle of the facility. A threat estimate
is a more focused prediction of the immediately probable. Threat estimates
are essentially short-term predictions of the likelihood of particular
threats based on recent "intelligence" information. They are relatively
important to operational security personnel, particularly security guard
commanders, because they relate to the desired state of readiness. Threat
estimates are particularly important in situations where physical security
has not previously been designed into a facility. If physical security has
been properly implemented into a facility to meet an appropriate design
threat, threat estimates are presumed included within the design threat
The choice of design threat must be based upon the assets being
protected. There is as much potential for diseconomies by selecting a design
threat that is too severe as there is for selecting one that is much too low.
Choice of any design threat, particularly a severe one, will almost always
influence the actual threat experience because the threat will respond to the
physical security design, appropriately, in the personnel, equipment,
tactics, and timing selected.