Regulations require that tank vessels handling grade B liquids shall have their cargo pumps separated from all sources of vapor ignition by（）.

单项选择题Regulations require that pumprooms on tank vessels carrying grade C liquid cargo with machinery spaces below the freeboard deck be ventilated with（）.

A.power ventilation
B.gooseneck vents and flame screens
C.at least two ducts extending to the weather deck
D.a vent header system

单项选择题Regulations require that cargo tanks carrying grades D or E liquids on tank barges be vented with（）.

A.gooseneck vents and flame screens
B.pressure-vacuum relief valves
C.branch vent lines and a vent header
D.forced draft blowers

单项选择题Regulations require that cargo pumps in tankers carrying grade D liquid cargo shall be isolatedfrom sources of vapor ignition by（）.

A.cofferdams
B.gastight bulkheads
C.passageways or living quarters
D.general cargo spaces

单项选择题Regulations require that cargo pumprooms on tank barges (constructed in 1965) carrying grades B or C liquid cargoes have power ventilation systems which can completely change the air in （）.

A.1 minute
B.3 minutes
C.5 minutes
D.10 minutes

单项选择题Petroleum cargo tanks should not be topped off at deck level when loading on a cold day because（）.

A.a subsequent temperature rise will cause the cargo to overflow
B.air pockets may cause the cargo to bubble out of the ullage hole
C.the increased viscosity of the product requires higher loading pressure which increases the chances of a spill
D.the tank valve may be stiff and a spill will occur before the valve can be closed