ETL 1110-3-485
15 Oct 97
Storage tanks may be part of an existing domestic water distribution system or a dedicated fire
protection water system.
5.2 Exterior Hose Demand. Where the water supply for the interior sprinkler systems also
supplies hydrants for exterior hose demands, a hose allowance of 1893 L/min (500 gpm) will be
included in the hydraulic calculations.
5.3 Duration of Supply. The water supply will be capable of supplying the maximum demand
for a period of not less than 60 minutes.
5.4 Underground Water Mains. Underground water mains will be installed in accordance with
NFPA 24, Installation of Private Fire Service Mains and Their Appurtenances.
5.5 Fire Pumps. Fire pumps will be installed in accordance with NFPA 20, Standard for the
Installation of Centrifugal Fire Pumps. Vertical shaft turbine pumps will be used where suction
lift is required.
5.5.1 Fire pump drivers will be either electric motors or diesel engines. When electric power is
economically available from a reliable single power source, or two independent sources in
accordance with NFPA 20, pumps will be electric driven only. Where such electrical power
supplies are not available, or cannot be provided, fire pumps will be diesel driven.
5.5.2 A minimum of two fire pumps will be provided. All pumps will be considered in meeting
the total system demand. An extra pump, as required by NFPA 409, will not be provided.
5.5.3 The maximum fire pump capacity rating will be 2,000 gpm. Pump pressure ratings will be
selected so the maximum pressure maintained on the system does not exceed 1035 kPa (150 psi).
5.5.4 A pressure maintenance or jockey pump will be provided for maintain pressure in the fire
protection piping system as specified in NFPA 20.
5.5.5 Fire pumps will be arranged for automatic starting upon pressure drop within the fire
protection piping system. Where preaction sprinkler systems are provided, fire pumps will also be
arranged for automatic starting upon tripping of any automatic water control valve.
6. FIRE PROTECTION SYSTEM DESIGN REQUIREMENTS
6.1 Designer Qualifications. Due to the importance and complexity of the fire protection
systems installed in helicopter hangars, it is essential that the design be accomplished by engineers
with extensive experience in design of fire protection systems described herein.
B-7
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