Section 46(3) in The Merchant Shipping (Fire Appliances) Rules, 1969
(3)In every ship to which these rules apply every pipe connected to any oil fuel storage, settling or daily service tank, not being a double bottom tank, which if damaged would permit discharge of contents so as to cause a fire hazard, shall be fitted with a valve or cock which shall be secured to the tank to which it is connected and which shall be capable of being closed from a readily accessible position outside the space in which the tank is situated, provided that in case of any inlet pipe to such a tank non-return valve, similarly secured to the tank may be substituted. In the case of an oil deep tank tranversed by any shaft or pipe tunnel a valve shall be fitted on the tank, but an additional valve or valves may be fitted on the pipe line or lines outside the tunnel or tunnels to enable control to be exercised in the event of fire.
