Water flow equation 1

[skdesigner]

I had it written down, lost it and for the life of me I can't remember how it goes.

Equation to figure out flow at a certain pressure when given static and residual. For example, I do a flow test and come up with x static and y residual pressure at some flow. I need to determine how much flow will be available at 20 psi.

I know that I can just use 1.85 graph paper, but for the sake of precision, does anyone have this equation handy?

Thanks in advance!

Steve

 

[cdafd]

maybe:

sorry cannot copy but:

Qr = Qf x hr(.54) power divided by hf (.54) power


where:
QR = flow predicted at desired residual pressure
QF = total flow measured during test
hr = pressure drop to desired residual pressure
hf = pressure drop measured during test

check this link for the formula:::

http://developmentservices.cityofox...ervices/Fire Flow Test Worksheet 11-25-09.pdf

 

[cdafd]

http://www.scribd.com/doc/63723117/...for-Fire-Flow-Testing-and-Marking-of-Hydrants

 

[skdesigner]

Much appreciated!

 

[MGXFP]

Qf=Qr((Hr^0.54/Hf^0.54)

Qf=flow at desired pressure (gpm)
Qr=flow at residual pressure (gpm)
Hr=(static - desired pressure) (psi)
Hf=(static - residual pressure) (psi)

 

[cdafd]

forgot about the "delta" symbol!!!!

 

[TravisMack]

Hey SK, shoot me an email and I will send you a flow test form in MS Excel that does the graphs and also gives you the flows at 20 psi. I got it from OSU's website long ago, so I don't believe it is an proprietary information or spreadsheet.

Travis Mack
MFP Design, LLC

http://www.mfpdesign.com