Best Practice Hydrant Test Data EPANET 1

[mjfarrell]

Hi guys, I am having some trouble getting pressures/flow to match the field test.

What is the best practice to model these test flows?
Reservoir to pump to node where the hydrant is?

Or Tank to node where the hydrant is

As an example one test location is 1244 gpm static pressure 102 psi and residual of 79 psi
I cant seem to get the flow/pressure correct at the first node where the hydrant is.

Any help or suggestions are greatly appreciated.

Thanks!

 

[hydrae]

Set a demand at the hydrant equal to the tested flow results.
Then figure out where the difference is, if the pressure is higher than expected, are all the pipes in the major flows new and clean, increase C value. Default is 100, brand new can be as high as 140
If pressure is lower than expected, and the pipes are old and rough, decrease C value.
If pressure is significantly lower than expected, is there a closed valve? or how reliable is the data on pipe sizes, materials and lengths.



Hydrae

 

[Pinwards]

Unless you have the entire distribution system (mains, PRVs, reservoirs, etc.) modeled, generally I would model the immediate vicinity of the project and then use a reservoir and pump, connected at the flow-tested hydrant, to simulate the distribution system that feeds the area. The pump curve uses your flow test data to set 3 points on the curve: static pressure at zero flow, the tested flow and residual pressure, and then you can use NFPA formulas to calc the available flow at the minimum allowed pressure (often 20 psi).

This thread describes it in a little more detail:

https://www.eng-tips.com/viewthread.cfm?qid=434937

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[mjfarrell]

Thanks guys, I'll give this a shot.

I think it's a one or the other as far as methods go, So I'll try each one and see how the model responds.

 

[mjfarrell]

OK guys I think it makes sense ...

IF I converted this flow test to pump curve correctly then I'm happy.

Is is possible to check the curve out for me?


Thanks for the advice!

 

[mjfarrell]

only one attachment?