The water pressure for fire sprinkler system stand pipe shall be a minimum 100 psi at the highest floor. Therefore, the pump pressure (Head) shall be calculated per pressure drop at equivalent length of the main pipe from the pump to the highest stand pipe at the highest floor, plus the static head (height of the main riser multiply 0.453 psi) and plus 100 psi (the minimum required pressure at floor stand pipe).
To determine the pump flow, for the 1st floor (stand pipe) 500 gpm and for each additional floor 250 gpm water flow should be considered. However, the maximum flow for the pump shall not exceed 1,250 gpm, no matter how many floors are in building.
Each fire pump system should be equipped with a main pump for the full use and a smaller pump (Jokey pump) for the periodic riser test and random use. The Jockey pump flow shall be maximum equal to 20% of the main pump flow and the pressure (head) equal to the main pump.
