Pump’s Head:
ht = hfl + hst + heq + hts
ht = Total pump’s head (ft)
hfl = Friction loss in developed length of longest pipe run in system per 4ft/100ft friction loss (ft)
*Developed length is total length of supply and return including equivalent length for fittings (rule of thumb: 3 times of supply pipe)
hst = Static pressure of system (elevation of water receiver or tank versus pump location)
heq = Pressure loss in the equipment in the end of the longest pipe run (if applicable) (ft)
hts = Total friction loss in suction pipe at pump (ft)
Pump’s Flow:
gpm = system’s demand per minute