AIR PIPES

Every tank on board ship must be provided with an air pipe; the purpose of providing an air pipe is to expel air from the tank during liquid filling operation and inlet air during liquid pump out operations. In other words, air pipes provide a passage way for inlet and expulsion of air during liquid movement, thus preventing Vacuum being formed in the tank.

The bore of the air pipe will much depend upon the volume of the tank to which it is fitted.

Every air pipe fitted to Double Bottom and deep tank which extends upto the shipside or any tank which may run up by the sea is always led above the Bulkhead (weather) deck.

Every air pipe leading from fuel tanks, cargo oil tanks, cofferdam having its opening above the weather deck must be of such height, where no danger will result from leakage of oil or its vapour.

The open end of the air pipes must be provided with closing arrangement, be fitted with weather tight closing arrangements, ball valve in the trunk of the pipe and spark arrester mesh on

the mouth of the air pipe, as required by the load line conditions assignment.

All exposed air pipes shall be of substantial construction, its height above the deck must be at the minimum 760 mm. in position - 1 and minimum 450 mm. In position 2; as far as possible, air pipes must be located in lee of the hatch / bulwark or such place where it has minimum exposure to damage.