Regular fire hydrant testing can improve a suboptimal ISO score simply by verifying a water system’s dependability under emergency circumstances. When properly maintained, a fire sprinkler system unobstructed by closed valves or disruptive mineral deposits is the most vital line of defense enabling firefighters to put out flames, limit property damage and prevent loss of life. For just that reason, the American Water Works Association (AWWA) recommends that every municipality flow test all areas every 10 years and requires flow testing for all underground and exposed piping every five years. Fortunately, this procedure requires little more investment than an affordable set of equipment and time to complete a brief, simple battery of steps.
Single Fire Hydrant Testing
No matter how many hydrants you evaluate, notifying your local water company or authority before fire hydrant testing allows your service provider to account for your tests potentially disrupting normal operating conditions. Your kit should a correctly sized nozzle for your hydrants, in addition to a water diffuser and sock to prevent landscaping or roadway damage and redirect water to avoid creating ice patches during the winter. Make sure all leaves and debris have been removed from drains, or water may back up and flood your testing areas.
Begin with the closest downstream hydrants from the building supply. The next-furthest downstream hydrant will serve as the secondary unit when taking a pilot reading. Move the pressure hydrant’s nozzle cap and equip the outlet with a pressure gauge. After completely opening the valve, you static pressure reading should register no flowing water. Finally, note any elevation changes from the pressure hydrant to the structure and flowing hydrant.
Next, fully open the flowing hydrant’s valve after ensuring all debris and obstacles have been removed from the flow path toward the pathway or drain and employing a diffuser if needed. Once the equipped pressure hydrant gauge needle stabilizes after several seconds of flow from the secondary hydrant, record the residual pressure. You will also collect the pitot reading by inserting the pitot tube orifice into the flowing water’s center a distance of half the opening diameter from the opening itself. The plane of the hydrant outlet face and the centerline of the orifice should form a right angle.
As your procedure nears completion, close the hydrant slowly to keep unwanted surges from damaging underground systems and equipment. Verify whether the hydrant outlet is rounded and smooth, square and sharp or square and projecting into the barrel by inserting your hand into the back of the outlet and record the size and type. Confirm that the hydrant is once more in service condition after closing all valves and checking for leaks.
What Should You Know After Fire Hydrant Testing?
By the end of a thorough test, you should have the basis for a well-informed system assessment based on the following collected data:
- Hydrant location, including street name
- Time of day when test was conducted
- Pressure Hydrant B static reading (system should exhibit no flow)
- Residual reading for Pressure Hydrant B during full flow
- Hydrant A flow reading from pitot gauge
- Water main diameter, measured in inches
- Hydrant outlet size and type, based on discharge coefficient
- Hydrant elevation
Based on this concise procedure, you should now have all information necessary to determine whether your water delivery systems are prepared for an emergency or timely renovations are in order. However, be mindful of your testing kit’s manufacturer specifications. Some products may differ in their exact usage instructions. Failure to notice some subtle-but-important distinctions may create an inaccurate data set.