OPEN COLD WATER NPSH

Go to the Hydraulic Institute Standards for more information.

This is the "Open Cold Water NPSH", it is more complicated than "Absolute NPSH", but it is used in the customary factory test.

What is the main different?

The tank was exposed to air, and the other is used with pure deareated water.

A series of points of various flow rates are run; 300gpm is one such point. This flow is constant and controlled by the flow control.

The suction valve is gradually closed until there is some evidence of cavitation, like a sound or a drop in the flow.