Total Positive Suction Head

It is possible to make sure that cavitation is avoided during pump operation by monitoring the total positive suction head of the pump. The net positive suction head (NPSH) for a pump is a difference among the suction pressure and the saturation pressure of the fluid being pumped. NPSH is employed to measure how close a fluid is to saturated conditions. The equation below can be employed to compute the net positive suction head available for a pump. Units of NPSH are feet of water.

NPSH = Ps_uction -P_saturation

Here:

P_suction = suction pressure of the pump

P_saturation = saturation pressure of the fluid

By sustaining the available NPSH at a level greater than the NPSH needed by the pump manufacturer, the cavitation can be avoided.