Tankerman · Inert Gas — Purging
Purging an inerted tank with additional inert gas before gas-freeing is done to:
- ARaise the oxygen level immediately
- BLower the hydrocarbon content so that, when air is admitted, the mixture does not pass through the flammable range✓ Correct
- CPressurize the tank for cargo
- DCool the cargo residue
Explanation
Purging reduces hydrocarbon vapor with inert gas first; then air is introduced for gas-freeing. Done in this order the atmosphere goes from too-rich/inert toward lean without passing through the flammable band.
Authority: SOLAS Chapter II-2; ISGOTT (purging and gas-freeing)
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