Section 33(3) in The Merchant Shipping (Fire Appliances) Rules, 1969
(3)In every ship required by these rules to be provided with fire pumps operated by power, the total pumping capacity of such pumps shall not be less than that specified below :(i)in the case of a passenger ship, the required fire pumps shall be capable of delivering a quantity of water, at the appropriate pressure prescribed in sub-rule (2), not less than two-thirds of the quantity required to be dealt with by the bilge pumps;(ii)in the case of a cargo ship, the required fire pumps, other than an emergency pump, shall be capable of delivering a quantity of water, at the appropriate pressure prescribed in sub-rule (2), not less than four-thirds of the quantity required to be dealt with by each of the independent bilge pumps in a passenger ship of the same dimensions when employed on bilge pumping. For this purpose diameter of the bilge main shall be calculated according to the following formulae (the actual internal diameter of the bilge main being the nearest standard size acceptable to the Central Government) :-d =d = internal diameter of bilge in millimetres where-L means length between perpendiculars in metres.B means greatest moulded breadth in metres.D means depth to bulkhead deck amidship in metres :Provided that in no cargo ship need the total required capacity of the fire pumps exceed 180 tonnes per hour.
