How much NPSH margin should I allow for a hot condensate pump?

Question

We are selecting a centrifugal pump to transfer hot condensate at 150 C from a flash vessel. The vessel operates at 4.76 bar abs and the liquid level gives about 3 m of static head above the pump suction. How do I calculate NPSH available and how much margin over NPSH required is good practice?

PlantCalcKit · Accepted Answer

NPSH calculation for hot condensate pump with margin guidance.