As per solas chapter II-1, regulation 21
Capacity of fire pumps
The required fire pumps shall be capable of delivering for fire-fighting purposes a quantity of water, at the pressure specified.
- Pumps in passenger ships, not less than two thirds of the quantity required to be dealt with by the bilge pumps when employed for bilge pumping; and
- pumps in cargo ships, other than any emergency pump,not less than four-thirds of the quantity required under Regulation II-1/21 to be dealt with by each of the independent bilge pumps in a passenger ship of the same dimension when employed in bilge pumping, provided that in no cargo ship need the total required capacity of the fire pumps exceed 180 m3/hour.
- The capacity of the pump shall not be less than40% of the total capacity of the fire pumps required and in any case not less than 25 m3/hour.
- Each of the required fire pumps (other than any emergency pump required for cargoships) shall have a capacity not less than 80% of the total required capacity divided by the minimum number of required fire pumps but in any case not less than 25 m3/hour and
- each such pump shall in any event be capable of delivering at least the two required jets of water. These fire pumps shall be capable of supplying the fire main system under the required conditions.
- Where more pumps than the minimum of required pumps are installed the capacity of such additional pumps shall be to the satisfaction of the Administration.
- Sanitary, ballast, bilge or general service pumps may be accepted as fire pumps, provided that they are not normally used for pumping oil and that if they are subject to occasional duty for the transfer or pumping of oil fuel, suitable change-over arrangements are fitted.
Fire main pressure
With the two pumps simultaneously delivering through nozzles , the quantity of water, through any adjacent hydrants, the following minimum pressures are to be maintained at all hydrants:
- vessels of 6,000 gross tonnage and upwards: 0.27 N/mm2 (40 psi)
- vessels of 1,000 gross tonnage and upwards, but under 6,000 gross tonnage: 0.25 N/mm2 (37 psi)