6.6 Use and control of inert gas
Clasification Society 2024 - Version 9.40
Statutory Documents - IMO Publications and Documents - Specifications and Manuals - Crude Oil Washing Systems - Revised Specifications for the design, operation and control of crude oil washing systemsResolution A.446(XI) Amended by Resolution A.497(XII) Amended by Resolution A.897(21) - 6. Operation - 6.6 Use and control of inert gas

6.6 Use and control of inert gas

 On ships to which these Specifications apply, no tank shall be crude oil washed unless the inert gas system required by Regulation 13B(3) of Annex I of MARPOL 73/78 is in proper operation. Before each tank is crude oil washed, the oxygen level shall be determined at a point 1 metre from the deck and at the middle region of the ullage space and neither of these determinations shall exceed 8 per cent by volume. Where tanks have complete or partial wash bulkheads, the determinations should be taken from similar levels in each section of the tank. The oxygen level of the inert gas being delivered during the washing process shall be continuously monitored. If during crude oil washing:

  • (a) The oxygen level of the inert gas being delivered exceeds 8 per cent by volume; or

  • (b) The pressure of the atmosphere at the tanks is no longer positive;

then the washing must be stopped until satisfactory conditions are restored.

Parent topic: 6. Operation
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