best grade coal not higher than 15 feet (4.5 m), unless they are piled by
roll-packing method. Locate yard piles at least 50 feet (7.6 m) from other
combustibles and important structures.
d) Coal bins, silos, or bunkers shall be constructed entirely of
noncombustible material, preferably concrete. The structure should be roofed
over to keep out rain and snow, and the space above the coal sufficiently
ventilated to prevent the accumulation of gases given off by the coal. An
elevated cone-shaped bin in which the coal is fed at the top and removed at
the bottom is recommended. This arrangement prevents fine materials from
collecting and remaining in the bin for long periods. The coal at the bottom,
which is most likely to be troublesome, is the first to be removed. Coal
bins, and when possible, bunkers and silos, should be emptied during the
summer shutdowns and other prolonged idle periods. Provide automatic
sprinkler protection if the existing storage facility has combustible
construction or occupancy other than coal. Provide access openings for manual
fire fighting operations.
e) Inactive coal piles, regardless of height are to be compacted
to prevent spontaneous heating.
Handling. Where combustible conveyor belts are used to transport
coal, the following shall be provided:
a) An automatic sprinkler system. It shall be hydraulically
designed to operate 10 automatic sprinklers and 2 hand-held hose lines (e.g.,
two 1-1/2-inch hose lines). Sprinkler spacing should be 100 square feet (9.3
m2) per head. The system should be designed for a flowing pressure of 10 psi
(70 Kpa) on the end sprinkler. Water supply should be adequate for at least
one-hour duration. Systems should be interlocked with the belt drive to shut
down on sprinkler water flow. In a conveyor enclosure less than 15 feet (4.6
m) wide, install a single line of sprinklers.
b) Provide either 1-1/2-inch hose lines or hydrants at suitable
intervals such that the entire belt is accessible for fire fighting.
c) Provide each conveyor belt system with tamperproof devices
arranged to automatically shut off driving power in the event of greater than
20 percent belt slow down or misalignment of belts. Interlocking devices
should also shut off power to contributing conveyors.
Pulverizing Equipment. Components of a pulverized fuel system shall
be designed and constructed in accordance with requirements of NFPA 8503,
Pulverized Fuel Systems.
Power Generating and Utilization Equipment
General. In general, electrical installations shall conform to NFPA
70, National Electrical Code. Specific details on the hazards of internal