Hydrant Flow Test
Hydrant Flow Test
(OP)
Hi,
We are designing a distribution system for a subdivision. We have had two hydrant flow tests done at this point and can't provide calculations that show that there is sufficient pressure for fire flow. There are 3 pump stations that pressurize the system we are tying in to. There was only 1 pump running at one station at the time of our last flow test. We feel that there is plenty of water pressure there (and please correct me if I'm wrong) due to the fact that the adjoining subdivision has water meters blowing off of the yokes due to the high pressure. We have spoken to the municipality about this and their response was to double check the calculations, which we have of course done several times.
How can we come up with a more accurate flow test? The line we are tying in to is a dead end 12" line with 2 hydrants upstream of where we are tying in. What result could be expected if we opened both hydrants and tested the hydrant on the subdivision frontage? Could that possibly cause additional pumps to kick on?
Thanks
We are designing a distribution system for a subdivision. We have had two hydrant flow tests done at this point and can't provide calculations that show that there is sufficient pressure for fire flow. There are 3 pump stations that pressurize the system we are tying in to. There was only 1 pump running at one station at the time of our last flow test. We feel that there is plenty of water pressure there (and please correct me if I'm wrong) due to the fact that the adjoining subdivision has water meters blowing off of the yokes due to the high pressure. We have spoken to the municipality about this and their response was to double check the calculations, which we have of course done several times.
How can we come up with a more accurate flow test? The line we are tying in to is a dead end 12" line with 2 hydrants upstream of where we are tying in. What result could be expected if we opened both hydrants and tested the hydrant on the subdivision frontage? Could that possibly cause additional pumps to kick on?
Thanks





RE: Hydrant Flow Test
RE: Hydrant Flow Test
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RE: Hydrant Flow Test
RE: Hydrant Flow Test
You don't mention tanks or reservoirs in your post. Are there any ?
You don't describe elevations of anything. What are the elevations of the pumps, hydrants, your project, the services which are being blown off their yokes, tanks ( if any), etc.
What fire flow do you need ? 500 gpm, 3000 gpm ?
What were the hydrant test results ?
Do you have EPANet or any similar modeling software ?
RE: Hydrant Flow Test
RE: Hydrant Flow Test
RE: Hydrant Flow Test
RE: Hydrant Flow Test
RE: Hydrant Flow Test
RE: Hydrant Flow Test
Thanks for the information.
First, the system already has higher than desirable pressures in some places. 150 psi is probably too high and can cause leaks, water hammer, and similar problems. Most systems I've worked on try to maintain system pressures between 40 psi and 85 or 90 psi.
Second, cvg is on track. Looping the system would help but it also sounds like the Water Utility should be seeking to enlarge some of the existing lines too. They should also be seeking to write a Master Plan and to include some storage reservoirs to provide fire flows and peak demands. The Master Plan must also address how high pressures can be reduced. Pressure reducing valves work but they waste energy so strategically placed storage is the preferred solution. ( maybe you can get them to hire you to write that plan ?)
Third, you may have to build that looped line earlier than you'd planned.
Fourth, you must ask the Water Utility to tell you how their pumps are controlled. Without that information you can't model the system and only they really know it.
good luck
RE: Hydrant Flow Test
RE: Hydrant Flow Test
RE: Hydrant Flow Test
http://virtualpipeline.spaces.msn.com
RE: Hydrant Flow Test
Generally, more pumps will provided better pressure/flow, however it is very dependent on the arrangement of the system, and how it is opperated.
RE: Hydrant Flow Test
RE: Hydrant Flow Test
Thank you!