单项选择题
A ship must have a self-contained breathing apparatus to be used as protection from gas leaking from a refrigeration unit. To meet this requirement，you may use（）.
A.a gas mask certified by the Mine Safety and Health Administration
B.the same self-contained breathing apparatus required with the fireman's outfit
C.an oxygen breathing apparatus，provided that the device has been inspected within three years
D.a portable ventilation system that will provide a complete change of air every three minutes
相关考题
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单项选择题
A ship helicopter landing deck on which fueling operations are conducted must have a fire protection system that is capable of discharging at 100 psi pressure a foam spray of at least（）.
A.30 gallons per minute
B.40 gallons per minute
C.50 gallons per minute
D.60 gallons per minute -
单项选择题
A portable foam (stored-pressure type) fire extinguisher would be most useful in combating a fire in（）.
A.generators
B.oil drums
C.the bridge controls
D.combustible metals -
单项选择题
A portable dry chemical fire extinguisher discharges by（）.
A.gravity when the extinguisher is turned upside down
B.pressure from a small CO2 cartridge on the extinguisher
C.air pressure from the hand pump attached to the extinguisher
D.pressure from the reaction when water is mixed with the chemical
