20 Oct 89
b) Electrical equipment in pulverizer areas should be suitable for
Class II (NEC designation) hazardous areas. In normally clean areas,
electrical equipment should be dust-tight (NEMA Type 5).
Power Generating and Utilization Equipment
General. In general, all electrical installations shall conform to
NFPA 70, National Electrical Code. Specific details on the hazards of
covered in the NFPA, Fire Protection Handbook, and the FM, Loss Prevention
Stationary Combustion Engines and Gas Turbines. NFPA 37, Stationary
Combustion Engines and Gas Turbines, shall be followed for internal combustion
engine and gas turbine and generator installations. Unless located in
sprinklered areas the following shall apply:
a) Isolated installations may be protected with a self--contained
pressurized sprinkler or water spray system with adequate supply to maintain a
density of 0.2 gpm/ft2 (8 1/min/m2) for 2,000 ft2 (184 in2) for
b) Where a turbine is installed as an individual unit in an
enclosure, a carbon dioxide system is acceptable as primary protection in
accordance with the following criteria for acceptance.
(1) For turbine compartments, the rate of discharge shall be
such that a 34 percent concentration of carbon dioxide is attained within 1
minute after actuation and a 30 percent concentration shall be maintained
throughout the deceleration period and until all metal surfaces likely to
reignite oil are cooled to below the autoignition temperature of the oil
400-500E F (204--260E C).
(2) For accessory compartment., to extinguish fires in
electrical equipment and oil, a concentration of 50 percent of carbon dioxide
shall be obtained within 1 minute after actuation. No less than 30 percent
concentration shall be maintained for the following 10 minutes.
(3) Where it can be established that fire temperatures will be
below the decomposition temperature of Halon 1301 (under 900E F [482E C]),
Halon 1301 shall be acceptable as an extinguishing system with provisions that
the Halon discharge is sufficient to maintain a minimum design concentration
of 5 percent throughout the deceleration period of the turbine.
Large individual units over 25,000 bp (18.63 MW) shall have
backup protection of automatic sprinklers.
Emergency generators shall be protected by a local
application of carbon dioxide.
Oil--Insulated Transformers. Fire protection equipment needed for
outdoor transformers depends on their size and importance. Table 7 provides