6.5 Additional purging and gas-freeing
Clasification Society 2023 - Version 9.38
Statutory Documents - IMO Publications and Documents - Specifications and Manuals - Inert Gas Systems - 6 Product Carriers - 6.5 Additional purging and gas-freeing

6.5 Additional purging and gas-freeing

 Gas-freeing is required on non-inerted product carriers more frequently than on crude carriers, both because of the greater need for tank entry and inspection, especially in port, and for venting vapours of previous cargoes. On inerted product carriers any gas-freeing operation has to be preceded by a purging operation (regulation 62.2.4), but gas-freeing for purely quality reasons may be replaced by purging only. In addition purging may be required on the basis outlined in 6.1.3 above.

It should be recognised that:

  • .1 there are increased risks of air leaking into inert tanks and of inert gas leaking into a tank being entered;

  • .2 purging is not a prerequisite of gas-freeing when the hydrocarbon gas content of a tank is below 2% by volume;

  • .3 the operation of gas-freeing for product purity and where tank entry is not contemplated does not require the atmosphere to have an oxygen content of 21% by volume.

Parent topic: 6 Product Carriers
Copyright 2022 Clasifications Register Group Limited, International Maritime Organization, International Labour Organization or Maritime and Coastguard Agency. All rights reserved. Clasifications Register Group Limited, its affiliates and subsidiaries and their respective officers, employees or agents are, individually and collectively, referred to in this clause as 'Clasifications Register'. Clasifications Register assumes no responsibility and shall not be liable to any person for any loss, damage or expense caused by reliance on the information or advice in this document or howsoever provided, unless that person has signed a contract with the relevant Clasifications Register entity for the provision of this information or advice and in that case any responsibility or liability is exclusively on the terms and conditions set out in that contract.