Water Hammer

A calculator for estimating pressure spikes (water hammer) caused by sudden changes in flow rate in pipes. Calculates the surge pressure resulting from rapid valve closure or opening, pump start/stop events, or pipeline bursts.

Water Hammer Calculator

A Water Hammer (or Surge) is a pressure spike caused by sudden variation of flow rate in pipes. This calculator estimates the pressure spike using the formula:

Δp = 0.070 × Δv × l / Δt

Where:

  • Δp = pressure spike (psi)
  • Δv = change in flow velocity (ft/s)
  • l = upstream pipe length (ft)
  • Δt = valve closing time (s)

Unit Conversions

  • 1 ft = 0.3048 m
  • 1 ft/s = 0.3048 m/s
  • 1 psi = 6894.8 Pa
  • 1 psi = 0.0689476 bar
Calculator

Inputs

Results

Pressure Spike (Imperial)-- psi
Pressure Spike (Metric)-- bar
Pressure Spike (Pa)-- Pa