Page 709 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide
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of intruders:
Fences 3 to 4 feet high deter casual trespassers.
Fences 6 to 7 feet high are too hard to climb easily and deter most
intruders, except determined ones.
Fences 8 or more feet high with three strands of barbed wire deter
even determined intruders.
A gate is a controlled exit and entry point in a fence. The deterrent
level of a gate must be equivalent to the deterrent level of the fence to
sustain the effectiveness of the fence as a whole. Hinges and
locking/closing mechanisms should be hardened against tampering,
destruction, or removal. When a gate is closed, it should not offer any
additional access vulnerabilities. Keep the number of gates to a
minimum. They can be monitored by guards. When they’re not
protected by guards, use of dogs or CCTV is recommended.
A turnstile (see Figure 10.4) is a form of gate that prevents more than
one person at a time from gaining entry and often restricts movement
in one direction. It is used to gain entry but not to exit, or vice versa. A
turnstile is basically the fencing equivalent of a secured revolving door.
