Getting Water Pressure at a Certain Height

[ThePeck]

It's been some time since I've had to deal with this but I believe I'm doing it the same and correct way. I have a building with a Fire Pump (Electric). And make sure at what height we can stop using pressure-reducing valves.

Water Flow Test Static= 88
Fire Pump Churn= 119
Total: 207 PSI

Assuming the water flow test was taken at 0'-0 elevation and the building's First Floor, Ground for non-USA, is also 0'-0. Then with the pressure loss due to height would require 32 PSI which is ~73'.

I was just reviewing an older project in which I did the same calculation, to verify I was doing it right, and they stopped using pressure-reducing valves about 76' before I would have.

 

[TravisMack]

Here is a quick / dirty calc:

207-175 = 32 psi

32 psi / .434 psi per foot = 74'. So, from the pump discharge up to ±75' you will need PRV for the hoses and control valves.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, a Ferguson Enterprise

http://www.mfpdesign.com