Estimating water flow from sprinkler main drain

[jimnogood]

Does anyone know how to calculate the K-factor (orifice opening) on a 2-inch main drain? I am trying to determine the water flow from the main drain at any given (static) pressure. I figured using the sprinkler formula Q=k*p^1/2 would be a close approximation. It is not for hydraulic calculations, but just to find out how much water is going down the drain during a test. Please help. Thx.

 

[cdafd]

there is one for open butt

I keep hearing that gpm calculations from main drain is not to accurate, but for what you are doing should work.



have to find the formula if you have access to a fire protection handbook will be there

 

[Oremus]

k=40.1

Just a guess...

 

[cdafd]

http://home.honolulu.hawaii.edu/~jkemmler/chapter2.htm

 

[cdafd]

If you are using the mathematical approach, the formula is:
29.83 x d2 x ?P x C = gpm
Where:
d = Inside diameter of the opening (in inches)
P = Pitot pressure, and
C = Friction coefficient

http://www.germanfiredept.org/Standard Operating Guidlines/Evaluating Water Supplies.doc

 

[cdafd]

http://www.1728.com/flowrate.htm