Hydraulics & Pressure
Elevation Pressure
EP
Elevation pressure is the pressure the pump must add or can subtract because the nozzle sits above or below the pump. Figure about 5 psi for each floor of rise, added on top of nozzle pressure and friction loss.
Water has weight, so lifting it costs pressure. Every floor the nozzle climbs above the pump is head the operator must add to the pump discharge pressure; a downhill lay gives some of it back. It is a real part of the PDP, separate from the hose's friction loss.
On a high-rise stretch, elevation can dominate the pump pressure calculation. That is why standpipe and high-rise planning treats a floor's worth of climb per level as a line item alongside the attack hose and the system allowance.
Where this shows up
Calculator
PDP BuilderLesson
Pump Discharge Pressure Builder