What is the correct customary formula for determining pump discharge pressure?

The customary formula for determining pump discharge pressure involves calculating the nozzle pressure and then adding the total pressure loss incurred in the system. This approach accounts for both the necessary pressure needed at the nozzle for effective water delivery and the various losses that occur within the system due to friction and other factors.

Nozzle pressure represents the pressure required to achieve a specific flow rate and pattern at the nozzle, which is crucial for operations such as firefighting. Total pressure loss includes the friction losses encountered as water moves through hoses and fittings, as well as any elevation changes that the water must overcome. By adding these two components together, you arrive at the actual discharge pressure needed from the pump to ensure proper operation.

The other options do not accurately represent the customary method for calculating pump discharge pressure: static pressure minus friction loss would suggest a decrease in pressure, which does not lead to an accurate calculation; friction loss multiplied by flow rate does not produce a pressure value; and pressure at the source plus altitude pressure does not take into account necessary factors affecting the actual discharge conditions, such as losses. The first option correctly combines the needed parameters for an effective calculation of discharge pressure.