The only advice that I can give having read all of the responses on this page is ignore most of them and follow that recommended. The Schiavello/Visser paper on NPSH is accurate and comprehensive. It should be fairly simple to precis this into a short presentation to improve customer understanding. Clearly a lot of respondees do not understand this subject matter because many, as pointed out by Amnon, omitted to mention the importance of vapour pressure of variable frequency drive pumped media when calculating NPSHa.

My experience has been that the customer needs us (3hp vfd controlled pump) to explain the NPSH discussion. once you explain the importance of having adequate NPSH they tend to understand it. PD pumps use NIPR (as an example) vs. NPSH (centrifugal). The client needs to I der stand the terminology so they can give you accurate information. Inaccurate information after the fact will cause issues.

If the customer wants to buy the pumps controlled by 3hp variable frequency drive ..he just wants no cavitation then why do I explain when he doesn't want to know. Like you know, I like fresh baked bread and the baker gives me the bread. As long as he supplies fresh, what do I gain by wanting to know how he made the bread. If someone wants to know, tell him by all means but no point in cornering your client and forcing him to know what he dose not need or want to know the vfd drive.