NPSH and Cavitation Risk Calculator
NPSH and Cavitation Risk Calculator
Check whether the planned suction installation provides the pump with sufficient NPSH margin and is not at risk of cavitation. A support tool for selecting submersible and industrial pumps.
NPSH (Net Positive Suction Head) is the excess pressure in the liquid above its vapor pressure, measured in meters of liquid column at the pump suction flange. NPSHa (available) describes the conditions in the installation, while NPSHr (required) is the minimum value that a given pump must receive at the specified operating point—the manufacturer provides it in the pump data sheet / curve.
If NPSHa falls below NPSHr, local vaporization of the liquid occurs at the pump impeller, vaporization and implosion of vapor bubbles—i.e., cavitation. This manifests as noise, reduced performance, and accelerated wear of the impeller and bearings, and in extreme cases, pump damage. Therefore, pump selection should always maintain a safety margin safety margin of NPSHa above NPSHr.
The calculator is for reference and to support pump selection. Actual conditions installation conditions (pipeline condition, exact pump data, operating temperature) may differ from the assumptions of the simplified model. In borderline cases and with unusual in installations, we recommend consulting Dambat's technical department.
