error : FDS was improperly set-up DEVICE Activation Times

[mohamme...@gmail.com]

Hello everyone,

I am running FDS simulation for a fire parking basement, and I encountered an error (FDS was improperly set-up DEVICE Activation Times). The basement has  three surfaces for make up air and  also three for the exhaust air, with a total of 17 jet fans.

I found that the problem is related to one of the supply air  vents and one of the exhaust vent . However, the problem was resolved, and the simulation is running smoothly when I shifted both the affected supply and exhaust vents away from the obstruction wall by one mesh size.

Kindly provide an explanation and  advise . Please excuse my beginner level .

thank you 

[fde]

When you move the VENTs, are you moving away from the obstruction surface or are they still attached to the obstruction?

[mohamed ata]

I move it away from  the obstruction wall , kindly see the attached photo . 

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[fde]

Hovering VENT should not work because VENTs need OBSTruction to attach. You can add a DEVC on top of the VENT to measure and verify if you actually have a flow. 
I see the obstructions do not align with the mesh. I assume you use the Pyrosim, therefore I suggest:

Convert the walls into obstructions which align the mesh,

then check if the VENT is at the correct location. 

[mohamed ata]

Yes, when I ran the result I found the vent does not work , I edited the wall obstruction to be aligned with the mesh grid and edited the location of the supply vent to be attached to the wall , and still have the same error .

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[fde]

If you get no error when VENT is removed, and get error when VENT exists, then the VENT properties might be wrong. Can you right click and copy FDS Records of the VENT and paste here to share?

[mohamed ata]

sorry for the delay in getting back to you , i modified all the obstruction wall to be aligned with the mesh grid , and re-added all the vent surfaces for the  make up air and the exhaust , i got a new error (SURF supply normal operation cannot be applied to a thin
obstruction FDS) then i modified the wall thickness to be the same mesh size , and it ran without errors , waiting the result , after i get it i will update you . 

Thank you . 

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