Section 13(2) in The Merchant Shipping (Cargo Ship Construction And Survey) Rules, 1974
(2)Without prejudice to the generality of the requirement of sub-rule (1), in boilers and machinery of every ship means shall be provided which will prevent over-pressure of any part of such machinery, boilers and other pressure vessels and in particular every boiler and every oilfired steam generator shall be provided with not less than two safety valves:Provided that the Central Government may, having regard to the output or any other feature of any boiler or unfired steam generator, permit only one safety valve to be fitted if it is satisfied that adequate protection against overpressure is provided.
