UFC 3 -520-01
June 10, 2002
Engine generators are used to provide backup power when the backup power
duration or the load requirement exceeds the capability o f a stationary battery system.
As the load increases or the discharge duration increases, a stationary battery must be
made correspondingly larger. In addition to the initial battery cost, the facility must be
made larger to accommodate a larger battery and the ongoing maintenance expense
will be higher. Although there are no firm limits and there will be natural exceptions to
any criteria, an engine generator should be used if the required backup power duration
exceeds 4 hours.
13-3.2. Emergency generators and related wiring systems are authorized for use when
needed to support the following types of applications and facilities:
Medical treatment facilities.
Air navigation aids and facilities.
Refrigerated storage rooms.
POL storage and dispensing facilities.
Critical utility plants and systems.
Civil engineer control centers.
Communication facilities and telephone exchanges.
Fire stations, including fire alarm, fire control, and radio equipment.
Critical computer automatic data processing facilities.
Air traffic control towers.
Base weather stations.
Surveillance and warning facilities.
Command and control facilities.
Security lighting systems.
Aircraft and aircrew alert facilities.