5.1 Inerting of tanks
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Specifications and Manuals - Inert Gas Systems - 5 Application to Cargo Tank Operation - 5.1 Inerting of tanks

5.1 Inerting of tanks

  5.1.1 Tanks that have been cleaned and gas-freed should be re-inerted preferably during the ballast voyage to allow the inert gas system to be fully tested prior to cargo handling. Purge pipes/vents should be opened to atmosphere. When the oxygen concentration of the atmosphere in the tank has fallen below 8% the purge pipes/vents should be closed and the tank pressurized with inert gas.

  5.1.2 During the re-inerting of a tank following a breakdown and repair of the inert gas system, non-gas-free and non-inerted tanks should be re-inerted in accordance with 5.1.1. During inerting, no ullaging, dipping, sampling or other equipment should be inserted unless it has been established that the tank is inert. This should be done by monitoring the efflux gas from the tank being inerted until the oxygen content is less than 8% by volume and for such a period of time as determined by previous test records when inerting gas-free tanks to ensure that the efflux gas is fully representative of the atmosphere within the tank.

  5.1.3 When all tanks have been inerted, they should be kept common with the inert gas main and maintained at a positive pressure in excess of 100 mm water gauge during the rest of the cycle of operation.


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