- Net Positive Suction Head ("NPSH")
Net Positive Suction Head is the total inlet head plus the head corresponding to the atmospheric pressure minus the head corresponding to the vapour pressure.
NOTE: ‘NPSH’ and ‘total inlet head’ are referred to in the reference plane. The two references to NPSH are as follows:
(a) Net positive suction head required (NPSHR) A function of pump design, which is available from the pump manufacturer.
(b) Net positive suction head available (NPSHA) A function of the system in which the pump operates and which can be calculated for any installation.