Tankerman · Equipment — P/V Valve
Pressure/vacuum (P/V) valves on individual cargo tanks allow the tank to:
- AStay rigidly sealed at all times
- BDischarge cargo overboard
- CRelieve small pressure/vacuum changes (e.g., from temperature) while normally containing vapors✓ Correct
- DMeasure ullage
Explanation
P/V valves let the tank breathe within set limits as cargo and ambient temperatures change, venting slight overpressure and admitting inert gas/air to relieve vacuum, while normally keeping vapors contained. They reduce structural stress and uncontrolled venting.
Authority: SOLAS II-2; ISGOTT
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