30 CFR § 75.1101-8
Water sprinkler systems; arrangement of sprinklers.
(a) At least one sprinkler shall be installed above each belt drive,
belt take-up, electrical control, and gear-reducing unit, and individual
sprinklers shall be installed at intervals of no more than 8 feet along all
conveyor branch lines.
(b) Two or more branch lines, at least one of which shall be above
the top belt and one between the top and bottom belt, shall be installed in
each sprinkler system to provide a uniform discharge of water to the belt
surface.
(c) The water discharge rate from the sprinkler system shall not be
less than 0.25 gallon per minute per square foot of the top surface of the
top belt and the discharge shall be directed at both the upper and bottom
surfaces of the top belt and to the upper surface of the bottom belt. The
supply of water shall be adequate to provide a constant flow of water for 10
minutes with all sprinklers functioning.
(d) Each individual sprinkler shall be activated at a temperature of
not less than 150° F. and not more than 300° F.
(e) Water systems shall include strainers with a flush-out connection
and a manual shut-off valve.