standards and guidelines for communication sites - Radio And ...

FIRE PROTECTION/SAFETY CHAPTER 3: COMMUNICATION SITE BUILDING DESIGN AND INSTALLATION
3.12.8 POWER SOURCES
The primary power source for the fire extinguishing system's operation and control shall have the
capacity for intended service and shall be reliable. Where failure of the primary power source would
jeopardize the protection provided, a secondary (standby) power source shall supply energy to operate
the system for a period of 24 hours and be capable of operating the extinguishing system continuously
for the full designed discharged period. The secondary (standby) power shall automatically transfer to
operate the system within 30 seconds of the loss of primary power.
3.12.9 FIXED SYSTEMS COMPARISON
TABLE 3-2 FIRE SUPPRESSION SYSTEMS
If a new system is being installed or an existing fixed fire-extinguishing system is being replaced,
always check with local fire prevention authorities and a competent fire protection engineer first. Be
ready to supply information about the material composition of the building or housing structure,
occupancy of the structure, environment, and equipment that needs to be protected. Ask for their
recommendations on the type of extinguishing systems needed, along with any advantages and
disadvantages of a particular system.
Some of the more common fixed systems currently used at communication sites are listed in Table 3-2.
The advantages and disadvantages of each type are also described.
Type Advantages Disadvantages
Water Extinguishing (Water
Sprinkler)
FE-13 (HFC-23)
• Upon detection of a fire condition, a “dry
pipe” type of system removes source power
to the room and then opens a master valve
to fill the overhead sprinklers. (The “dry
pipe” system is preferable to a “wet pipe”
system, which has the chance of water
leakage and resultant equipment damage
and possible electrical shock.)·
• No adverse environmental impact.
Clean Agent Extinguishing System
• Environmentally friendly replacement of
Halon 1301-based systems.
• Advantage over CO2 systems, due to FE-13
lack of oxygen displacement characteristic.
• Electrically nonconductive and residuefree.
No cleanup is required after discharge
and system downtime can be kept to a
minimum.
• The storage cylinder(s) may be stored away
from the protected area.
• Storage cylinders can be stored in a wide
range of temperatures; containers need not
be stored in protected places at room
temperature.
• System recharge is less expensive than
alternative fluorocarbon agents.
• If power connections are made beneath
raised floors, waterproof electrical
receptacles and connections are required.
• Either type of water sprinkler system could
cause electronic equipment damage and
will require an extensive cleanup effort.
• Upon discharge, system downtime can be
lengthy.
• May not be readily attainable or easily
refilled in certain areas.
• Typically much more costly to purchase and
maintain than water systems.
• When released under fire conditions
hydrofluoric acid (HF) can be produced.
3-28 68P81089E50-B 9/1/05