Deck General USCG Question #1220 (Set 38)

During loading, what is the minimum pressure required to be maintained by the inert gas system on cargo tanks?

Official USCG Answer & Rule Citation

Correct Answer: Option B — 4" water gauge

Title 46 CFR 32.53 and SOLAS Chapter II-2 require the inert gas system (IGS) to maintain a minimum positive pressure of 100 mm water gauge (approximately 4 inches water gauge) in the cargo tanks during loading. This positive pressure prevents the ingress of atmospheric air and maintains a non-flammable atmosphere.

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