Calculation of NPSHa where tank is in closed condition

[Loo Kian Sing]

Can gauge pressure in a closed tank and vapor pressure of the fluid be cancelled off in calculation of NPSHa?
If yes, what is the condition needed?
What is mean by closed tank? The tank is fully closed and there will be no liquid enter the tank? Or the tank is enclosed but with several pipe connected (Vent, product inlet, nozzle for pressure safety valve)?
Thank you if anyone can provide me some information or answer.

 

[LittleInch]

No.

You need to use the pressure on the liquid surface in absolute terms and vapour pressure in absolute terms.

Just put in all the terms, don't start cancelling things off.

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