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regulations for tankers (International Maritime Organization, 1974).

Inert gas generators are used to produce the inert gas with less than 5%

oxygen would be provided. An inert gas main would be provided with branch

connections to all cargo and slops tanks. A high velocity P,/V valve would be

provided on the inert gas main, to ensure the safe venting of the inert gas

containing hydrocarbon gas without risk of ignition.

A common vent main is installed with branch connections to all cargo and

slop tanks, to facilitate the gas freeing of the tanks for inspection or maintenance.

The system has a high velocity type P/V valve to ensure that neither a dangerous

overpressure nor under pressure can occur inside any tank whilst it is out of service

for maintenance or inspection.

Tank Washing System

A Crude Oil Washing (COW) system serves the cargo and slop tanks. The
COW is connected to the offloading line and branched off to all cargo and slop

tanks. A booster pump installed in the system raises the pressure during offloading,
should the loading pump pressure in the COW main be insufficient for crude oil

washing.

Ballast Water System

A ballast water ring main system is used to fill and discharge the segregated

wing ballast tanks. All ring main ballast piping runs over the deck so as to avoid

any possible contamination with crude oil.

All valves used for routine operation in the ballast water system are

hydraulically operated and remotely controlled from the central control room.

Fire Water System

The fire water system supplies:

Fire water to:

 Deck foam system

 Helideck foam system

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