2 cissp ® Official Study Guide Eighth Edition

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Chapter 10 
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Physical Security Requirements
Know the terms commonly associated with power issues.
Know the definitions of the 
following: fault, blackout, sag, brownout, spike, surge, inrush, noise, transient, clean, and 
ground.
Understand how to control the environment.
In addition to power considerations, main-
taining the environment involves control over the HVAC mechanisms. Rooms contain-
ing primarily computers should be kept at 60 to 75 degrees Fahrenheit (15 to 23 degrees 
Celsius). Humidity in a computer room should be maintained between 40 and 60 percent. 
Too much humidity can cause corrosion. Too little humidity causes static electricity.
Know about static electricity.
Even on nonstatic carpeting, if the environment has low 
humidity it is still possible to generate 20,000-volt static discharges. Even minimal levels of 
static discharge can destroy electronic equipment.
Understand the need to manage water leakage and flooding.
Water leakage and flooding 
should be addressed in your environmental safety policy and procedures. Plumbing leaks 
are not an everyday occurrence, but when they occur, they often cause significant damage. 
Water and electricity don’t mix. If your computer systems come in contact with water, espe-
cially while they are operating, damage is sure to occur. Whenever possible, locate server 
rooms and critical computer equipment away from any water source or transport pipes.
Understand the importance of fire detection and suppression.
Fire detection and suppres-
sion must not be overlooked. Protecting personnel from harm should always be the most 
important goal of any security or protection system. In addition to protecting people, fire 
detection and suppression is designed to keep damage caused by fire, smoke, heat, and sup-
pression materials to a minimum, especially in regard to the IT infrastructure.