ETL 1110-3-484
26 Sep 97
mark-up identify which original CEGS provisions have been deleted and which have been
modified. Assure that the final specification reflects the changes accepted during the design
review process.
10. TECHNICAL GUIDANCE.
10.1 Fire Protection Water System.
10.1.1 General. In most instances, fire pumps taking suction from aboveground water storage
reservoirs will be required for hangar foam fire suppression systems. Except for filling of water
storage tanks, avoid connections to domestic water systems.
10.1.2 Locate water storage tanks and associated pumping facilities as close as practicable to the
hangar facilities or hangar groups being protected. Size tanks for 120% of the supply needed to
meet the calculated demand for the duration required by applicable design criteria. Where
required by applicable design criteria, divide water storage tanks into two approximately equal
sections, so at least one-half of the water supply will always be maintained in service. As a
practical matter, two interconnected tanks provide the most suitable means for meeting this
requirement. Arrange tanks for automatic filling in accordance with NFPA 22, Water Tanks for
Private Fire Protection.
10.1.3 Maximize the reliability of the underground water distribution system piping by looping
mains where feasible. This is particularly applicable to water systems supplying multiple hangars.
Limit dead end configurations as much as feasible. Generally, dead end mains should be limited to
no more than 457 m (1500 ft). Provide underground sectional control valves to allow isolation of
impaired sections of piping to minimize the number of facilities to be adversely affected by an
impairment.
10.1.4 Provide fire pumps with rated capacities of 3785 L/min (1,000 gpm), 5678 L/min (1500
gpm), 7570 L/min (2000 gpm) or 9463 L/min ( 2500 gpm). If required by applicable criteria,
provide one additional pump so the maximum water demand can be met with the largest pump
out-of-service. Minimize the pressure rating of the pump as much as possible, but in no case
design for normal system pressures exceeding 1207 kPa (175 psi).
10.1.5 Drivers for fire pumps will be electric motor or diesel engine as specified by applicable
design criteria. Where electric pumps are provided, assure that electric power is arranged in
accordance with NFPA 20, Centrifugal Fire Pumps. Provide a pressure maintenance (jockey)
pump in accordance with NFPA 20.
10.2 AFFF Concentrate Supply.
B-8
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