The IMO requirement on Tanker Safety and Pollution Prevention, annex I - regulation 13B (3) states "an Inert Gas System shall be provided in every cargo tank and slop tank in accordance with the appropriate regulations of chapter II-2 of the international convention for the Safety of Life at Sea (SOLAS), 1974, "

(and) 1983-amendment to the international convention for the SOLAS, 1974-regulation 62 (inert gas systems) paragraph 17 states "portable instruments for measuring oxygen and flammable vapour concentration shall be provided. In addition, suitable arrangement shall be made on each Cargo tank such that the condition of the tank atmosphere can be determined using these portable instruments. "

(and) 1978 ? resolution A. 446(XI) , 6.6 (use and control of inert gas) states "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.

When oxygen level is measured by portable gas detector (oxygen meter etc) which will be supplied by shipowner or manufacturer of inert gas system in compliance with above IMO requirement, MMC Gas Sampling (Sealing) Attachment (with Calibration Cock) is applicable for gauging job by portable instrument at MMC Tank Gauging Station (Vapor Locks) installed on tank top to be required as suitable arrangement.