I am trying to run a automated fire flow scenario, however I would like the flex table to stop calculating or display once 3500 gpm is reached or 20 psi residual. I have set up the following (see image) but my flex tables will not calculate up to 3500 gpm when the residual is not 20 psi?
Hi, the fireflow could still stop before 3500 gpm or 20 psi residual if the zone pressure constraint (which you have set to 0 psi) is violated or if the network becomes unbalanced.
If you're not already on the latest version (10.04.00.108) I recommend upgrading since we've made several improvements to fireflow reporting over the past few most recent versions (which you can read about here). If you're on the latest version, you can see the "reason" for why the fireflow stopped, which should give you insight into whether it was the zone pressure constraint or unbalanced network that is stopping your fireflows short.
If the problem is the zone pressure constraint, it could be due to a junction at a high point or pump suction side experiencing negative pressures, which you could place in another zone or exclude. See: Fire flow nodes are failing because of low pressures on the suction side of a pump
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
i only have one pressure zone in my system. i am also not getting a network becomes unbalanced error?
If you only have one pressure zone, that means that if the pressure falls below zero at any node in the network during an individual fireflow run, it will stop. The network unbalanced would not show as an error / notification because it would occur during an individual fireflow event. You will need to look at the "Fire flow status" column in the fireflow Flextable along with the other fields to determine why the fireflow stopped short.
See:
I looked at the fireflow status and it says passed for all the nodes.
I did notice that the pressure (calculated zone lower pressure) was 0 psi for those runs that did not continue to 3500 gpm or 20 psi? what does that mean?