BRANDCO FIELD RESOURCES
How to Perform a Fire Hydrant Flow Test
A useful hydrant flow test connects three observations: pressure before test discharge, pressure while water is flowing, and the discharge rate. Brandco wireless equipment brings pressure readings from the measurement hydrant to the technician working at the flow location, making coordination easier.
This field-planning guide is for qualified testers. The water authority’s approved procedure, equipment instructions, and applicable requirements govern the actual work. NFPA 291 addresses water-flow testing and hydrant marking; AWWA M17 covers hydrant installation, field testing, and maintenance.
1. Define the test and obtain authorization
Establish whether the test is evaluating the distribution water supply, checking an individual hydrant, or supporting a particular design. Those objectives can require different measurement arrangements. For a typical distribution-supply test, pressure is observed at a measurement hydrant while one or more other hydrants discharge.
Confirm hydrant selection with the water authority, including the main arrangement and relevant operating conditions. Agree on notifications, the permitted discharge route, operational limits, and who may operate the hydrants. Do not assume owning test equipment authorizes operation of a public hydrant.
2. Prepare the site and instruments
Identify where water will travel, including downstream runoff. Provide the required traffic protection, drainage measures, hose restraint, and protective equipment. Check hydrant condition, matching threads, fitting pressure ratings, and instrument calibration status before connecting. Local provisions can differ: Lafayette’s guidance identifies location-dependent drainage and diffuser requirements.
Prepare a test cap and pressure instrument at the measurement point, plus a suitable flow-measurement arrangement at each discharge. Use the equipment manufacturer’s instructions for flushing, venting trapped air, installation, and valve operation. A pressure reading from the wrong connection can be precise yet answer the wrong question.
3. Add wireless pressure visibility
The Brandco Water Supply Test set combines a Pressure Sender, Remote Display, and hydrant test cap. Connect the sender through the compatible cap connection at the static/residual hydrant, then carry the display to the discharge location. Confirm that the correct sender is identified and communications are reliable before flowing water.
If your existing test cap is compatible, the Basic Remote Water Pressure Gauge set provides the sender and display. Wireless transmission changes where you can read the pressure; it does not replace the discharge instrument or the approved test layout. Brandco’s hydrant testing guide illustrates this arrangement.
4. Capture static pressure, then flow and residual pressure
Record static pressure with no test discharge occurring and with the measurement connection prepared correctly. Then conduct the flowing portion under the approved procedure. When readings stabilize, record residual pressure and flow at the same operating condition. If several outlets are flowing, identify each outlet and account for the total discharge.
A Dual Wireless Water Pressure Gauge set adds a second pressure sender for a compatible flow-device gauge port. With flow calculation enabled and the correct device data entered, the display can show remote pressure and calculated GPM together. The sender measures pressure; the flow result depends on the measurement device and its settings.
5. Restore the site and complete the record
Close valves slowly according to the hydrant and system instructions. Restore the hydrants, check the site, and remove equipment only after pressure is safely relieved. Do not use the wireless display as a substitute for safe valve operation or a complete restoration check.
Record hydrant IDs and locations, date and time, static pressure, simultaneous residual pressure and flow, instrument identification, flow-device settings, and unusual conditions. Clearly separate measured discharge from any calculated available-flow result. A complete report makes a later comparison far more useful than an isolated pressure number.
Frequently asked questions
Can a wireless sender replace a pitot or flow device?
No. It supplies pressure data. Flow must be established with an appropriate measurement method and, where applicable, the correct conversion settings.
Does every test use exactly two hydrants?
No. The objective and water-system layout determine the arrangement. Obtain approval for the selected method.
How often should the test be repeated?
Use the schedule required for the system and test purpose. Inspection, flushing, and water-supply flow testing are different activities.
Related resources
Understand static and residual pressure · Build your equipment checklist
References
NFPA 291 · AWWA M17 resources · Brandco hydrant testing guide · Lafayette flow-test requirements