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EPAnet: FireFlow and Tower placement

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BadLatitude

Civil/Environmental
Oct 24, 2016
2
I'm completely new to EPAnet and water distribution in general but was tasked with solving the placement of a new water tower for a small town (to be reviewed by someone with actual experience); however, Im having issues with testing fire flow. What is the proper way to set up my Junction for a fire flow test of 1500gpm with a duration of 2 hours? My model seems to work fine when running on regular demand but when I attempt to test fire flow I get some wildly negative pressures.

I've attached the the model and the fire flow junction I'm trying to test is the western most point.

Thank you in advance for any help!

Jameson
 
 http://files.engineering.com/getfile.aspx?folder=2302a82c-8ff7-4eed-8cef-cde8ba95c152&file=161028_JH_-_Modified.net
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Just a quick look

Interesting, a totally flat town sitting at sea level, all the elevations are zero

Sorry but I typically work in imperial units, so you model in SI is not intuitively obvious to me at first glance. also your post is in imperial and the model is in SI. Use one or the other

You have the pumps stacked on top of each other so you cannot see the operation of the pumps in the map, you can offset them and correct the pipe lengths for easier viewing

You have warnings that pumps that are closed because they cannot deliver heads at the times called for in the rules, I would fix the rules to get rid of the warnings. ie make like real life.
also are your pumps called by a master flow meter as the rules list? or are they called under low pressure, and secured at high pressure and/or low flow out of that pump. If so change the rules to match how the system operates. This may cause some instability as it cannot decide to run a pump or not; if so, add some short lengths of pipe complete with minor losses (minor losses are not minor near a complex set of piping) in the network between the pumps as they are in real life

Demand category
a fire is at one place not spread out over the whole town, use the demand category at the location of the proposed fire to up the flow only at that location and leave the other nodes alone again just like real life

you got your work cut out for you

Hydrae

 
Thank you for your input Hydrae. I actually don't have any rules set, the model is using GPM and I have elevations set for every node, they are low, but this is very near see level. I just downloaded the model I posted to confirm. Are you sure you were looking at the correct model? 161028_JH_-_Modified.net
 
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