When conducting flow tests and the desired flow (gpm) for the test is not obtained via a single 2-1/2" fire hydrant outlet, should additional flow be achieved by opening an additional 2-1/2" outlet on that SAME fire hydrant, or should a single 2-1/2" outlet be opened on an ADDITIONAL fire hydrant?
So for multiple 2-1/2" outlets opening and flowing, should this be done:
I have heard people say that (A) is correct and (B) is incorrect, and vise versa. Thank you. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
11 Comments
Alex
9/13/2022 06:18:50 am
Hi,
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Dan Wilder
9/13/2022 07:59:56 am
This will be interesting...I am in the (A) school of thought.
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Eric R
9/13/2022 08:27:31 am
I don't see this question so much as an either/or but more of priority of selection. Opening the second 2.5" on the hydrant is an easy first step, and there certainly isn't anything wrong in doing so. From there, if you still need more water then a second hydrant should be opened up,
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Jay
9/13/2022 10:01:17 am
The intent is to flow more outlets on a single hydrant. You flow more than one hydrant only if you can't achieve the pressure drop or flow you're seeking from the single hydrant.
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Jesse
9/13/2022 10:03:23 am
Multiple hydrants, and NFPA 291 has some great examples of where the additional hydrants can be in relation to the test hydrant.
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Joe F
9/13/2022 10:20:38 am
I agree with Dan & Eric. (A) If you can achieve the desired 25% drop in pressure with a single hydrant flowing both ports that is completely acceptable. If not add additional hydrants as needed.
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Dave
9/13/2022 11:05:18 am
I am with the majority (so far) above, the greatest majoriy of the the time we flow the (2) 2-1/2" on one hydrant, which in my experiernce is usually sufficient. If additional drop is needed, we flow two from an appropriately selected additional hydrant (if available). I agree with Eric as well, not so much an either/or.
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Chris
9/13/2022 11:32:34 am
Where I live the typical water supply is very strong, sometimes as good as 90-100psi static pressure with drops of only 5-10psi while flowing 1100gpm+. So when working with LH and OH we generally only flow one outlet, but when working with ESFR or storage we flow multiple outlets.
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Franck
9/13/2022 01:01:39 pm
You can do both
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Glenn Berger
9/13/2022 02:52:04 pm
As others have said, you need to follow NFPA 291 as the recommended practice for hydrant flow testing.
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schulman
9/15/2022 06:12:55 am
constantly receiving flow tests NOT done to NFPA 291 ...makes my job difficult if not frustrating. Please do tests per NFPA 291 if you are a testing contractor !!!
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