the alarm. If the goal is to prevent removal of the sensitive material from
the fenced area, the guards must intercept the adversary within 8 minutes of
Barrier Penetration Performance
Forcible Entry Barrier Penetration. A barrier is penetrated when
an intruder can pass through, over, under, or around the structure.
Penetration time includes the time to create a man-passable opening [96
square inches (0.06 square meter (sq m))] and traverse the barrier. Barrier
penetration time is a function of the selected attack mode which is governed
by the equipment required. Categories of attack tools are described in par.
As an intruder encounters a series of barriers, it becomes increasingly
difficult to transport and set up bulky or sophisticated tools. This is
especially true if it is necessary to pass through a series of small
openings. The accessibility of the restricted area to vehicular traffic may
also be affected. When the adversary is forced to carry heavy equipment for
long distances without the aid of vehicles, the delay times may become
Section 5 presents penetration time information to be used in evaluating or
selecting barriers to protect against forced entry.
Ballistic or Standoff Weapon Barrier Penetration. A barrier is
penetrated by a standoff or ballistic weapon, when a shaped-charge jet or
bullet either penetrates or causes sufficient secondary spall to kill or
injure personnel on the other side of the barrier. Section 6 addresses
methods for hardening against ballistics, and Section 7 against standoff
Vehicle Barrier Penetration. A vehicle barrier can be considered
penetrated when the ramming vehicle has passed through the barrier and is
still functioning, when a second vehicle can be driven through the breached
barrier, or when the vehicle barrier has been removed or bridged and a
vehicle has passed through or over the barrier. Vehicle barriers designed to
prevent penetration are addressed in Section 8.
Intrusion Detection. The detection of an intruder can be
accomplished using either on-site guards, IDS, or some combination: (1) at
the exterior perimeter fence line of the site, (2) at or on the surface of
barriers associated with the building, or (3) within the interior volume of
all or part of the building.
Exterior Detection Along the Site Perimeter. Locating guards in
towers or deploying sensors along extended fence lines adds to the intruder's
ingress/egress time to cover the distance from the fence to the building,
i.e., the clock starts earlier with detection along the fence. This option,
though, typically involves high operating costs for guards or, if sensors are