HomeMy WebLinkAbout012-Hydrant Flow TestFIRE HYDRANT FLOW TEST
Location:Prince Street
Hydrant #:3049
Date:2/10/2023
Time:By COBWeather and Temp:
Headwaters #:1204.003
Data collected during the test:
Flowed Hydrant 3049Static Pressure, Ps (psi)115
Pitot Pressure, P (psi)70
Flowrate during test, Qt (gpm)1405
Residual Hydrant 3063Static Pressure (psi)115
Residual Pressure during test (psi)108
Calculations:
Discharge Coefficient, Cd 0.85Outlet diameter, D (in)2.5
Unit conversion factor, Cf (29.8 English)29.8
Hydrant discharge, Q (gpm)=Cf*Cd*D2(P)1/2 1325
Residual Pressure @ flowed hydrant, Pt (psi)108
Hazen-Williams Formula: QR=Qt*((Ps-Pr)/(Ps-Pt))0.54
Desired residual pressure, Pr (psi)20
Fire flow at residual pressure, QR (gpm) =5,416
Pressure vs. Flow curve data points at flowed hydrant:
P (psi)Head Q (gpm)
115 266 0
89 205 2,708 Pr = Ps-(Ps-Pt)(Qr/Qt)1.85
20 47 5,416
Note: Hydrant discharge, Q, is calculated as a check for the reliability of Qt
above
Note: QR is calculated to evaluate the capacity of the distribution system
near the tested hydrant at a given residual pressure. Note: Rearrange the Hazen-Williams formula to provide a rough
estimate of residual pressure at a flow data point near the average
of 0 gpm and flow at 20 psi and enter that data point into the graph
above for water modeling purposes.
0, 266
2,708, 205
5,416, 47
0
50
100
150
200
250
300
0 1,000 2,000 3,000 4,000 5,000 6,000Pressure, P (psi)Flow, Q (gpm)
Water Main Pressure vs. Flow Capacity
H:\1204\003\DOCS\DESIGN\Hydrant Flow Test.xls Printed: 4/7/2023