Analytically find the 100% in a fire pump curve 1

[Ciaci]

Hi,
I have some equally spaced point of a fire pump curve (flow rate-pressure). The data-sheet doesn't show the rated capacity. Is there a way to analytically find it? How the producer of fire pump determine it, once the experimentally obtain the pump curve?
Thanks

 

[LittleInch]

If this is a centrifugal pump then the "rated" flow is quite a large range. Typically the preferred flow is within 10% of BEP, but fire pumps work to a different way of thinking.

They need to be able to flow 150% of rated flow I think without disintegrating.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Ciaci]

Thanks. How can I find the BEP?

 

[LittleInch]

Its plotted on the pump curve.

Usually found by testing I think.

BEP =Best Efficiency Point
Example and guidance below.

Often shown as contours like this.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Ciaci]

Ok... I can't find it in the catalogue. I think I should ask to the producer tomorrow. It could have been nice to calculate it by myself. Thanks!

 

[CarlB]

This site gives a formula to calculate efficiency, you can determine the best for the few points you have

https://www.psgdover.com/griswold/n...mizing-pump-performance-best-efficiency-point

This site says BEP is at about 85% of shutoff head

https://allpumps.com.au/find-best-efficiency-point-pump/

 

[LittleInch]

Beware that fire pumps work to a a different way of thinking altogether.

Efficiency is irrelevant, it just needs to be able to pump what it needs to and then do 150% of flow without falling to bits.

Oh and survive regular dead head / no flow ( the latest NFPA codes are a bit better) for 30 minutes at time every week and survive.

Efficiency is quite possibly not measured....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.