Second, calculate the NPSH available (NPSHa). This value represents the absolute pressure available at the pump inlet. If the NPSHa is 3 feet more than the NPSHr, the pump will not cavitate. Be aware, NPSHr is measured under ideal conditions for repeatability and accurate bench...
NPSHr is the minimum amount of pressure required on the suction side of the pump to avoid cavitation, or the introduction of air into the fluid stream. NPSHr is determined by the pump. You always want NPSHa>NPSHr. NPSHa, with "a" standing for available, is determined by the process ...