While testing a cargo tank，your oxygen indicator reads 25% o

The purpose of inert gas systems aboard tank vessels is to ______.

A.allow sufficient oxygen in the tank to sustain life

B.prevent outside air from entering the tank

C.provide increase in cargo discharge pressure

D.comply with double hull pollution prevention regulations

You are carrying triethylamine，methyl methacrylate and isoprene in your multiple-product tanker. Which of the following statements is true?

A.Isoprene may be carried in a cargo tank adjacent to either of the other two cargoes

B.Methyl methacrylate may not be carried in a tank adjacent to a pump room

C.Methyl methacrylate must usually be heated to maintain its stability

D.Portable thermometers are not permitted to be used to take the cargo temperature of triethylamine

Before entering a fuel tank that has been cleaned, it should be checked with an oxygen indicator and a/an ____.

A.Orsat apparatus

B.flame safety lamp

C.Halide torch

D.combustible gas indicator

Inerting means ______．

A.The introduction of inert gas into a tank with the object of reducing the oxygen content to below 8% by volume

B.The introduction of inert gas into a gas free tank for the purpose of reducing the oxygen content to below 8% by volume

C.The introduction of inert gas into a cargo tank during cargo discharge to replace the volume of discharged cargo

D.All of the above

The sign used to caution persons approaching the gangway of a tank barge during cargo transfer reads ______．

A.Warning，Keep Off，Stay Clear

B.Danger，Do Not Board

C.Warning，No Smoking，No Open Lights，No Visitors

D.Dangerous Cargo Being Transferred

When measuring the oxygen content of the cargo tanks prior to loading cargoes requiring vapor recovery，check it ______.

A.one meter from the tank bottom and one meter below the tank top

B.one half the ullage of the tank and one meter below the tank top

C.one half the ullage of the tank and one meter above the tank bottom

D.at three meter intervals from the tank top to the bottom

While testing a cargo tank，your oxygen indicator reads 25% oxygen in the tank. You would then ______.

A.enter the tank safely

B.suspect the accuracy of the reading

C.ventilate the tank

D.test for nitrogen

An inert gas system installed on a tanker is designed to ______.

A.aid in the stripping and cleaning of cargo tanks

B.increase the rate of discharge of cargo

C.force toxic and explosive fumes from a cargo tank to vent to the outside atmosphere

D.lower the oxygen levels inside cargo tanks，making explosion nearly impossible

You are testing a tank that contained gasoline by using a combustible gas indicator．Under testing，the tank sample caused the needle to move rapidly to 100 on the dial then fall to zero．What is the concentration of flammable gas ________．

A.Less than the flammable range

B.Within the flammable range

C.Over the flammable range

D.The explosimeter is defective and giving a false reading

Your tanker is carrying a cargo of styrene．Which of the following is NOT a requirement for carriage of this cargo ________．

A.P/V valves with galvanized parts must be replaced

B.Authorization to carry styrene must be endorsed on the Certificate of Inspection

C.You must have a Certificate of Inhibition provided by the shipper

D.The cargo tank heating coils must be blanked off