Nothing better than answering your own question...
The equation is
Available water = Q mutliplied by square root(D2/D1)
where available water is flow rate in gpm
Q = flow rate of flowing hydrant in gpm
D2 = static pressure - assumed residual pressure of 20 psi
D1 = static pressure - actual...
I have been given a table of fire flows at various hydrants by a city. A column provides a calculated flow rate for the given hydrant at 20 psi, the max fire flow if you will. I cant remember the equation used to determine this rate. I seem to remember it is a form of the energy equation. As...