Net Positive Suction Head (NPSH): Why It Matters in Pump Performance


Net Positive Suction Head (NPSH) is one of the most important factors in the safe and efficient operation of centrifugal pumps. It refers to the pressure available at the pump suction side, specifically at the impeller eye, to keep the liquid from vaporizing as it enters the pump.

When liquid flows into a pump, pressure naturally drops due to the velocity increase and suction effect created by the rotating impeller. If this pressure falls below the liquid’s vapor pressure, vapor bubbles begin to form. These bubbles collapse violently once they move into higher-pressure areas inside the pump, causing a damaging condition known as cavitation.