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Fire Duration

Dear Bentley,

I create fire flow scenario for system consist of tank, fire pump and water network, I set up the fire parameter and run the model, that is ok as usual as normal project, now let us say the fire duration is Two hours, how can I make this scenario duration two hours, i.e. i would to make the fire pump to run for that duration and would make report for that duration, in other words, I would to investigate my system during that period (check the tank levels, pump, the pressure in my system............), how can I adjust my scenario accordingly??

Regards,

Mohamad Azzam

  • Hi Mohamad,

    You need to perform an extended-period simulation (EPS). Set up the fire flow node as a normal demand, with the base demand equal to the desired fire flow. The base demand should have an associated demand pattern in stepwise format with a multiplier of 0 for the times when you do not want fire flow, and a multiplier of 1 for the 2-hr duration you want to use to simulate the fire.

    Regards,

    Kristen Dietrich

  • Mohamad,

    To add to what Kristen said, quick start lesson 2 (Extended Period Simulation) illustrates a similar situation (3 hour fire). You can also look at the "Fire 1625" scenario in the Example4 model included with WaterCAD and WaterGEMS. By default this would be located under C:\Program Files\Bentley\WaterGEMS\Samples\


    Regards,

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

  • Hi Jesse,

    I have checked quick start lesson 2 and we do not have any fire scenario where you mentioned that included (3 hours fire).


    Also I have looked into Example4 "Fire 1625" and run the model but when you go fire browser you will not able to see fire results and in the calculation options> calculation type, it is Hydraulic Only and even in Alternative > Fire Flow > Base-Fire flow was not setup as a fire. Please may you guide me more about how I should do that scenario.

     

    Mohamad Azzam,



  • Mohamad,

    You need to follow the steps in the help for quick start lesson 2, to see the 3 hour fire.

    The fire flow results browser and fire flow alternative are only used for the automated fire flow routine. To model a fire occurring for a specific period of time, an EPS simulation is required. You cannot use the automated fire flow routine with an EPS simulation. So, if you need to model 3-hour fires occurring at multiple hydrants, you'll need to manually change the pattern for each of the hydrants and run a series of EPS simulations. The results can be checked like any other EPS simulation. For example, you could create a graph of pressure over time for the hydrant where the 3 hour fire occurs, or the tank level.


    Regards,

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

  • Oh; I see what you mean. Thank you Jesse,