Overflow pipe test

An overflow pipe test checks that a tank’s overflow arrangement and its high-level alarm work together to prevent overfilling and spillage during loading and bunkering. The trial fills the tank to the overflow level and confirms the overflow pipe discharges freely to its designed destination (an overflow tank or save-all) and that the high-level and overfill alarms trip at their set points. Overflow and air-pipe arrangements on cargo, ballast, and fuel tanks follow SOLAS and MARPOL anti-pollution requirements and the class piping rules; bunker tank overfill protection is checked to MARPOL Annex I save-all and alarm provisions. A blocked overflow or a silent alarm is a pollution and structural overpressure risk.