Program Policy Manual - VOLUME V - Mine Safety and Health ...

MSHA PROGRAM POLICY MANUAL VOLUME V
It is important that sprinklers be located so as to be actuated by
the heat from a potential fire. The sprinklers shall operate in
the temperature range 150 o F to 300 o F. Under some circumstances,
sprinklers operating below 212 o F may be actuated by steam.
If a large number of sprinklers are actuated by steam, the
quantity of water flowing through these may decrease the quantity
of water through those sprinklers in the fire area.
Sprinklers cannot be tested directly for the yearly functional
examination without destroying their usefulness. In order to test
a sprinkler system, the end sprinkler should be removed to
ensure adequate water flow. The sprinklers should be free of
dirt, and all damaged sprinklers should be replaced.
Sprinkler system lines are normally filled with water. Where
freezing temperatures exist, the pipes may freeze and burst, or
ice may form and plug the lines. Alternative systems developed
for this situation are:
1. Regular dry pipe system.
2. Preaction system.
3. Deluge system.
4. Combined dry-pipe and preaction system.
These alternative methods are acceptable provided they offer
equivalent protection and are installed in accordance with the
provisions of the Fire Protection Handbook published by the
National Fire Protection Association.
75.1101-13 Dry Powder Chemical Systems; General
Suppression at belt drives by all-purpose dry powder was included
to serve primarily where freezing temperatures exist. The dry
powder system operates for a short period of time (1 minute)
whereas the deluge or sprinkler systems operate for 10 minutes or
longer. Therefore, the dry powder system must be carefully
designed to be effective. The discharge pattern from the nozzles
is critical, and, normally, the locations of the nozzles shall be
designed by an expert. Damaged or misaligned nozzles should be
replaced promptly. The dry powder system consists of an open
pipeline system. In order to prevent moisture and dust from
entering pipes, the nozzles should be loosely covered. This can
be achieved by tape covering, by water-proof grease or equivalent
means. Caps that are tightly fastened should be checked to ensure
they will blow off readily; screw caps are unacceptable. If
October 2003 (Release V-34) 102