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

MSHA PROGRAM POLICY MANUAL VOLUME V
1. The entry width does not exceed 16 feet, and the entry
height is not less than 6 feet;
2. The static water pressure is not less than 250 psig and
the quantity of water delivered with all nozzles operating
is not less than 1.0 gallon per square foot of top belt
surface area per minute; and
3. The nozzles are mounted above the top conveyor belt near
the roof, and reasonable water coverage of the belt
surfaces is achieved by splashing action.
The maximum distance between nozzles shall not be more than 8 feet
to achieve a reasonable water spray pattern. In general, the
nozzles need not be closer than 6 feet apart.
The regulations require that 50 feet of fire-resistant belt and
150 feet of nonfire-resistant belt adjacent to the drive be
protected. Depending on ventilation, design, and belt
arrangement, this 50 (or 150) feet of protected belt should begin
at the discharge roller if the discharge roller and drive roller
are not more than 25 (or 75) feet apart. Where the discharge
roller and drive rollers are more than 25 (or 75) feet apart, the
protected area should include 25 (or 75) feet of adjacent belt in
each direction from the drive roller. Where air velocity is a
factor, the greater part of the protected area should be downwind
from the drive roller.
The type, number, and location of the sensors are critical
features of a water deluge system. There are about a dozen basic
types of sensors which can be used, i.e., fixed temperature
(heat), rate of temperature rise, rate compensation, radiation,
ionization, combustion gases, smoke, heat detecting wire,
pneumatic tube type, and resistance bridge type.
The location of the sensors should, in general, be in accord with
the recommendation of the manufacturer. Sensors responding to
heat should be located near the roof, preferably above the belt,
drive rollers, powered takeup unit, transmission, and motor.
Often, one sensor can be situated strategically to serve two of
the possibly hazardous units.
75.1101-5 Installation of Foam Generator Systems
Automatically-operated high-expansion foam devices may be used for
fire suppression at belt drives. The capacity of the unit shall
be sufficient to cover 50 feet of fire-resistant belt conveyor
(150 feet of nonfire-resistant belt) as well as the takeup and
gear reducing units and electrical controls with foam in 5
October 2003 (Release V-34) 100