航海英语海上消防单项选择题每日一练(2018.10.14)

单项选择题
High-velocity fog（）.
A.is a finer，more diffuse water spray than low-velocity fog
B.requires that the water pressure be no greater than 60 psi
C.produces an effective fog pattern no more than 6 feet beyond the nozzle
D.extinguishes a fire by absorbing heat and reducing the supply of oxygen
单项选择题
On a hydrocarbon flammability chart the line which extends from 0% to 21.8% oxygen，lying tangent to the flammability range，is called the（）.
A.minimum oxygen content line
B.critical displacement line
C.critical dilution line
D.upper threshold limit
单项选择题
Each part of the fire-main system located on an exposed deck must be（）.
A.protected against freezing
B.locked to prevent theft
C.numbered sequentially
D.pressurized at all times
单项选择题
According to the T-Boat regulations the reason for providing adequate ventilation for a battery storage area is to prevent（）.
A.accumulation of carbon dioxide gas that chokes the battery
B.accumulation of explosive and toxic gases the battery can generate
C.mildew or dry rot in the battery box
D.battery failure including battery case meltdown caused by excessive heat
单项选择题
Any extinguishing agent used on a Class C fire must have which important property?（）
A.Cooling ability
B.Leaves no residue
C.Penetrating power
D.Nonconductivity