Tankerman · Safety — Inert Gas
A cargo tank is generally considered properly inerted when the oxygen content is held at or below:
- A21 percent by volume
- B15 percent by volume
- C8 percent by volume✓ Correct
- D5 percent by volume
Explanation
Inert gas systems are required to keep tank oxygen at or below 8 percent by volume (with a positive pressure), well under the level needed to support combustion of hydrocarbon vapors.
Authority: Tank Vessel Safety (USCG topic)
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