ETL 1110-3-485
15 Oct 97
a. Smooth ceiling, joists consisting of steel truss-shaped members, or wood truss shaped
members that consist of wood top or bottom chord members not exceeding 102 mm (4 in) in
depth with steel tube or bar web.
b. Wood beams of 102 mm by 102 mm (4 in. by 4 in.) or greater nominal dimension, concrete
or steel beams spaced 0.9 to 2.3 m (3.5 to 7.5 ft) on centers and either supported on or framed
into girders.
c. Paragraphs (a) and (b) apply to construction with non-combustible or combustible roof or
decks.
d. Construction with ceiling panels formed by members capable of trapping heat to aid the
operation of sprinklers with members spaced greater than 2.3 m (7.5 ft) and limited to a maximum
of 27.9 m2 (300 ft2) in area.
4.4.5 The floor area covered by an individual water-only sprinkler system in helicopter hangar
bays will not exceed 2321 m2 (25,000 ft2).
4.5 ESFR Sprinkler System Design Requirements.
4.5.1 Systems will be hydraulically designed to provide a minimum sprinkler operating pressure
of 345 kPa (50 psi) for all sprinklers in the design area.
4.5.2 The design area will consist of the hydraulically most demanding thirty (30) sprinklers.
4.5.3 The maximum allowable protection area of coverage for a sprinkler will be 9.3 m2
(100 ft2). The minimum allowable protection area of coverage for a sprinkler will be not less than
24.4 m2 (80 ft2).
4.5.4 The maximum distance between ESFR sprinklers on branch lines or between branch lines
will be not more than 3.0 m (10 ft) and the minimum distance will be not less than 2.4 m (8 ft).
4.5.5 ESFR sprinkler temperature rating will be intermediate with a temperature rating range of
93 oC to 104 oC (200 oF to 220 oF). The maximum ambient temperature at the underside of the
roof or ceiling will be at least 10 oC (50 oF) less than the sprinkler temperature rating.
5. FIRE PROTECTION WATER SUPPLY.
5.1 Water Storage. Sprinkler and exterior hose demands will be supplied by one or more
elevated or ground level storage tanks of sufficient capacity to meet the calculated demands.
B-6
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