Tankerman · Operations — Gas Freeing
When gas-freeing a previously inerted tank for entry, the recommended practice is to:
- APurge with inert gas to lower hydrocarbons, then ventilate with air to raise oxygen—avoiding passing through the flammable range with air✓ Correct
- BAdd more inert gas
- COpen all hatches and let air mix freely from the start
- DHeat the tank
Explanation
Purging first with inert gas drives the hydrocarbon content below a safe level, so that when air is then introduced the mixture does not pass through the flammable range. Only after testing confirms a safe, oxygen-normal, gas-free atmosphere may entry occur.
Authority: ISGOTT; SOLAS II-2
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