IPF Rev0204
8
TYPICAL APPLICATIONS
Hydrant Total Flow Test
A direct reading of flow in Gallons Per Minute (GPM) can be obtained by
connecting the portable flow tester to a discharge, flow water and record the flow
displayed. The tester can also be used (employing some simple math) to find the total
output of a hydrant. This can be accomplished by recording the differences in flow
out of one discharge as other ports on the hydrant are opened.
The hydrant test method described below assumes the use of a portable flow
tester with a 2.5" flow tube. If a different size tube is used, the mathematical calculations
below would need to be adjusted.
The Portable Flow tester may be connected to the 2.5" hydrant port in order to
obtain individual hydrant flow measurements. Other ports may be opened as desired.
To conduct this test, proceed as follows:
1. Connect the flow tube to a 2.5" port. (Adapters are not supplied.)
2. Open the hydrant valve and record the flow reading.
3. Shut off the hydrant and remove the other 2.5" cap.
4. Open the hydrant valve and record the flow reading.
Note:
This reading will be lower than the first reading as the water is now
being discharged from two ports.
5. If the hydrant has a steamer port, open that and record the flow as above.
If more than one port is opened, the total actual flow will be higher than the
displayed flow, but it will be in proportion to the opened port areas. The actual flow
can be determined by multiplying the displayed flow by a
"K" factor
such that:
Total Actual Flow = Displayed Flow x K
Use the values for "
K
" in Table 1 to determine actual estimated flow.
Table 1. Values for K With a 2.5" Flow Tube
PORTS OPENED
K
One 2.5" port with 2.5" flowmeter attached
1.00
Two 2.5" ports, one with 2.5" flowmeter attached
2.00
One 2.5" with 2.5" flowmeter attached and one 4.5 “ steamer
4.24
Two 2.5", one with 2.5" flowmeter attached and one 4.5" steamer
5.24
