Page 1587 - (ISC)² CISSP Certified Information Systems Security Professional Official Study Guide

Chapter 10: Physical Security Requirements

1. A fence is an excellent perimeter safeguard that can help to deter

casual trespassing. Moderately secure installations work when the
fence is 6 to 8 feet tall and will typically be cyclone (also known as
chain link) fencing with the upper surface twisted or barbed to
deter casual climbers. More secure installations usually opt for
fence heights over 8 feet and often include multiple strands of
barbed or razor wire strung above the chain link fabric to further
deter climbers.

2. Halon degrades into toxic gases at 900 degrees Fahrenheit. Also, it
is not environmentally friendly (it is an ozone-depleting
substance). Recycled halon is available, but production of halon
ceased in developed countries in 2003. Halon is often replaced by a
more ecologically friendly and less toxic medium.

3. Anytime water is used to respond to fire, flame, or smoke, water
damage becomes a serious concern, particularly when water is

released in areas where electrical equipment is in use. Not only can
computers and other electrical gear be damaged or destroyed by
water, but also many forms of storage media can become damaged
or unusable. Also, when seeking hot spots to put out, firefighters
often use axes to break down doors or cut through walls to reach
them as quickly as possible. This, too, poses the potential for
physical damage to or destruction of devices and/or wiring that

may also be in the vicinity.