Work out pump head requirement instantly with clear inputs, formula shown and shareable results.
Pump head is the static lift plus the friction the pipework imposes. Friction comes from Hazen-Williams with a C factor of 140 for plastic pipe, and a further 20 percent is added for bends, valves and fittings. Hydraulic power is rho g Q H, divided by pump efficiency to give shaft power.
Hazen-Williams
hf = 10.67 L Q^1.852 / (C^1.852 D^4.87), Q in m³/s and D in m
Power
kW = 9.81 x Q L/s x total head / (1000 x efficiency)
hf = 10.67 L Q^1.852 / (C^1.852 D^4.87), Q in m³/s and D in m. Pump head is the static lift plus the friction the pipework imposes.
Each bend, tee and valve behaves like extra pipe length. On a compact installation with many fittings the allowance can exceed the straight pipe loss, so it should be assessed properly rather than assumed.
This calculator takes 4 inputs: Static head, Total pipe length, Design flow, Pipe internal diameter. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.