View Full Version : Hydrant Curve not finishing at 0 psi

DavidCoD

September 15, 2016, 12:43 PM

On my previous version of the model, all of my hydrant curves would finish at zero pressure. This new version sometimes does not. I have some curves that end at 45 psi. Must be a simple setting I am missing. Any help will be greatly appreciated. Thanks

Patrick Moore

September 15, 2016, 03:38 PM

David,

I gave you a call but must have just missed you so we could look at your model together to see what might be going on.

Can you verify the version of the software you are running?

Generally, if you are not getting results past a certain point, that is indicative that the model was unable to find a solution for flows above the point in question. The easiest way to test that is to use the multi-fireflow tab in the run manager and only select the node used in the hydrant curve using a flow just higher than what is shown and it will run a standard analysis with that on the node in question. You can then review the results and see what may be occurring.

If you set the report options to use a full report and generate warning messages as shown below: you can review the full report and see if it provides insight to why the hydrant curve fails to run it's expected length.

(click for a larger image if necessary)

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Search for warning messages in one of the last iterations of the report for reaching maximum trials or not able to find a solution.

If you need further assistance please contact us at support@innovyze.com and we can help you further with a quick WebEx meeting.

Patrick Moore

Patrick Moore

September 20, 2016, 10:41 AM

David,

Just to follow up for the sake of the forum. Per our call you were using an older version of InfoWater (12.2 update 1) and I just wanted to follow up and let you know that the matter you raised was successfully resolved. Please download the latest update (InfoWater 12.3 Update 2 is the current latest version at the time of this post and has this issue resolved). Thank you.

Please visit our software update page to get the latest up to date product updates on this web Page:http://www.innovyze.com/updates/

Patrick Moore

Patrick Moore

September 26, 2016, 02:02 PM

To clarify a few things for our other users based on follow up discussions, one last thing you can do if you see this issue is to first run a fireflow or multi-fireflow for the junction to get a sense of what flow would be expected for 20 psi and then adjust your Report Flow Increment value so that 0 psi would be reached within 51 iterations of the hydrant analysis.

51 total report points on any hydrant curve should easily give a nice smooth curve for the full flow range as long as a reasonable increment value is chosen. Simply adjust the flow increment so that the interval will achieve close to 0 psi at the maximum iteration and be under 51 total points. Example: 0 psi expected at 10,000 gpm then 10,000/50 = 200 so an interval of 200 gpm would get to 10,000 gpm after 50 points. Simply divide the expected flow at zero by 50 to get a maximum flow interval to start with and adjust as necessary.

In this model the max flow was very large (over 30,000 gpm) and the interval was initially set to 150 gpm which was too small to reach near zero pis within 51 total iterations. When adjusted to 1000 gpm interval, the software produced a nice smooth curve with under 51 points and had a final result just under 2 psi for the last point which is generally acceptable as close enough for most hydrant curves.

Hydrant curve (click if need larger image)

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Patrick Moore