Tanker Familiarization Inert Gas Systems 2

Question 1

What does 'gas-freeing' of a cargo tank involve?

Accepted Answer

Ventilating the tank with fresh air to replace inert gas and reduce hydrocarbon vapors for safe entry

Answer

Gas-freeing ventilates a cargo tank with fresh air to displace inert gas and dilute hydrocarbon vapors to safe levels, restoring sufficient oxygen for personnel entry.

Question 2

What is the primary function of the scrubber in an inert gas system?

Accepted Answer

To cool and clean the flue gas by removing sulfur dioxide and soot particles

Answer

The scrubber cools the hot flue gas and removes harmful impurities including sulfur dioxide (SO₂) and soot before the gas is delivered to the cargo tanks.

Question 3

Before personnel enter a tank that has been held in an inerted condition, what action is absolutely essential?

Accepted Answer

Gas-free the tank until oxygen is at least 19.5% and hydrocarbon levels are below the LFL

Answer

Before entry, the tank must be fully gas-freed so oxygen is restored to a breathable level (≥19.5%) and hydrocarbon concentrations are confirmed below the lower flammable limit.

Question 4

What is the correct procedure before loading flammable cargo into a tank that currently contains a normal air atmosphere (21% oxygen)?

Accepted Answer

Inert the tank to reduce oxygen below 8%, then proceed with loading

Answer

Before loading flammable cargo into a tank containing air, the tank must be inerted (oxygen reduced to below 8%) to eliminate the risk of an explosive atmosphere forming during loading.

Question 5

What does a pressure/vacuum (P/V) valve on a cargo tank protect against?

Accepted Answer

Both excessive over-pressure and excessive vacuum within the cargo tank

Answer

P/V valves protect cargo tanks against structural damage by opening to relieve both excessive positive pressure buildup and dangerous negative pressure (vacuum) within the tank.

Tanker Familiarization Practice Test

Tanker Familiarization Practice Test

Tanker Familiarization Inert Gas Systems 2