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Fire flow Failed

Hello,

I have run the fire Flow Scenario and I am wonder how some nodes pass the analysis in spite of  the pressure (Calculated system lower limit) is negative? please any clarifications??

 

 

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Regards...................Mohamad Azzam

  • Mohamad,

    Unfortunately your screenshots are a bit too blurry for me to read. This is a technical support problem, so please submit a service ticket using the online ticket manager at selectservies.bentley.com We'll be glad to help you.

    Note that we have a technote that goes into great detail on how to troubleshoot fire flow results. Please see below:

    communities.bentley.com/.../understanding-automated-fire-flow-results-tn.aspx


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

  • Dear Jesse,

    I already have service ticket {ticketno:[8000926605]}, and have last email not been replied. and I will add this inquiry to the same service ticket.

    how can I post those screen shots to that service ticket?

     

    Regards,

    Mohamad Azzam

  • Mohamad,

    I just replied to your service ticket.  You can reply back to my email with screenshots and new revision of the model as an attachment (in a zip folder), if you have made any changes.

    Regards,

    Nancy



  • Mohamad,

    No doubt the tech support group will tell you this, but these comments may help you or someone else....

    It looks like you have the 'Use Minimum System Pressure Constraint' option unchecked. This means the fire flow calculations will ignore pressures that are outside the zone which your fire flow node is located in, which would explain why nodes pass fire flow constraints even though there are some negative pressures in the system.

    Leaving this option unchecked is useful in certain cases - like where you have some pumps with a suction pressure that is lower than your fire flow limit and you want to ignore them in your fire flow calculations. (Without this option, the low suction pressure at the pump would result in all nodes always failing the fire flow contraints).

    However, if you do want the fire flow calcs to look at pressures throughout the system (and not just within a single zone), you should check the  'Use Minimum System Pressure Constraint'  option and add a minimum pressure constraint for the system (the "System Lower Limit"). Note, this limit can differ from the minimum pressure at the fire flow node (the "Residual Lower Limit"), or within the fire flow node's zone (the "Zone Lower Limit").

    Regards,

    Mal

          

  • Mal,

    I appreciate your reply, that exactly 100% what I wanted to hear. Thanks for all bentley.

    Mohamad Azzam