Reg. 30.4.2
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Statutory Documents - IMO Publications and Documents - International Conventions - MARPOL - International Convention for the Prevention of Pollution from Ships - Unified Interpretations of Annex I - 57 Small diameter line - Reg. 30.4.2

Reg. 30.4.2

  57.1 For the purpose of application of regulation 30.4.2, the cross-sectional area of the small diameter line should not exceed:

  • .1 10% of that of a main cargo discharge line for oil tankers delivered after 1 June 1982, as defined in regulation 1.28.4 or oil tankers delivered on or before 1 June 1982, as defined in regulation 1.28.3 not already fitted with a small diameter line; or

  • .2 25% of that of a main cargo discharge line for oil tankers delivered on or before 1 June 1982, as defined in regulation 1.28.3 already fitted with such a line. (See paragraph 4.4.5 of the revised COW Specifications contained in resolution A.446(XI) as amended by the Organization by resolutions A.497(XII) and A.897(21)).

  57.2 Connection of the small diameter line to the manifold valve.

The phrase “connected outboard of” with respect to the small diameter line for discharge ashore should be interpreted to mean a connection on the downstream side of the tanker’s deck manifold valves, both port and starboard, when the cargo is being discharged. This arrangement would permit drainage back from the tanker’s cargo lines to be pumped ashore with the tanker’s manifold valves closed through the same connections as for main cargo lines (see the sketch shown in appendix 3).


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