In pump calculations, what does PDP stand for?

• A. Pressure Drop Parameter.
• B. PUMP DELIVERY PRESSURE.
• C. Pump Discharge Pressure.
• D. Pneumatic Diffusion Pressure.

Answer: (C)

In pump calculations, PDP refers to the pressure on the discharge side of the pump—the pressure the pump must develop to push water through the hose and appliances to the nozzle. This discharge pressure is what you compare against the required nozzle pressure after accounting for friction losses in hose and fittings and any elevation changes. The term is standard for describing the pressure the pump must produce at its outlet. The other options don’t reflect the usual hydraulic term used in these calculations, so Pump Discharge Pressure is the best fit. For example, if the nozzle needs 100 psi and you’re facing 40 psi of hose friction losses plus 10 psi of elevation head, the pump must deliver about 150 psi at discharge.