Thursday, April 3, 2014

Fire Hydrant Flow Test



Pressure Gauge on Non-Flowing Hydrant

In order to determine if the water supply is adequate for a fire sprinkler system, it is often necessary to perform a fire hydrant flow test.  NFPA 291 gives specific requirements for how a flow test is to be done.  One hydrant upstream of the flowing hydrant has a pressure gauge on it.  When the second hydrant flows, there is a drop in the pressure at the upstream hydrant.  A gauge measures the pressure of the flowing hydrant and a pitot tube is used to measure the water flow.  Given this information and the type of hydrant, it is possible to determine the water flow rate at 20 psi.  If the flow is adequate at that pressure, great. Otherwise, it may be necessary to increase the size of the water supply main or add a fire pump.

Flowing Hydrant with Diffuser Attached
 
Flowing Hydrant with Hose Monster Attached

2 comments:

  1. I read your blog on daily basis. This is really great and informative post. Thanks for sharing.
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