Using Fire Flow Data

[SkinnyDip]

I am designing utilities for small subdivision and have been given hydrant flow data near the site. I tried using this with EPANET and straight line piping (conservative, assuming no network) but could not maintain fire flow. Now I have to be more specific and take the network into calculations. We have 2 connections to separate water mains to the subdivision and 2 hydrant flow data. How do I use this in EPANET? Each hydrant was tested separately so I don't know how one hydrant in use affects the other hydrant. In other words. I can't use each hydrant as a separate pump curve serving the site because that would assume that each acts individually but actually they are on same network. I just reread my question and it is confusing. Anybody run into this problem or find a solution?

 

[coloeng]

When ever we do flow tests for a new subdivision,, that will connect to the existing system at more than one point, we usually do the flow tests for both hydrants at the same time. If the water supplier you are dealing with is willing to do the same, you can then model them as two pumps because you will see the effect on the total system at the same time. Hope this make sense.

 

[RWF7437]

It should NOT be necessary to model the whole system unless the subdivision is very large in comparison to the water system.

Use the flow test data ( static pressure and elevation) to estimate the overflow elevation of the reservoir or reservoirs serving your subdivision. Assuming your subdivision lies totally within one pressure zone there will be only one overflow elevation to deal with.

Then, model only the part of the existing and proposed systems in, and adjacent to, your subdivision. You can make the simplifying assumption that the reservoirs ( real or simulated )are at overflow. Your controlling case will almost certainly be during extreme fire flow demands with other demands at maximum day levels. This should be specified by the Water Supplier and the Fire Department.

Unless there are actual pumps involved you don't need to model any pumps or make any assumptions about them unless the Water Supplier provides you data. You can't make this stuff up ! For a fee, they may be willing to model this for you.

If you MUST model the entire system then you will need a great deal of data. This data can ONLY be obtained from the Water Supplier, along with their guidance on what demand cases they require you to model.

I am just completing a similar project in California and would be happy to send you and example. To avoid problems with the website ignore the dashes:

rwf-7437-at-comcast-dot-net

good luck

 

[SkinnyDip]

Hey,

Thanks for your input. I would really appreciate it if you could send me an epanet file of something similar to what I am dealing with. I know how to do it if there was only one connection to a source or if there was 2 connections to 2 separate sources, but struggle with 2 connections to the same source with each flow dependent upon the usage of the other. Again, I couldn't put it in more confusing words. But thanks for your help.