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Author Topic: ''New slab'' and ''New obstruction''  (Read 2436 times)

JLo

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''New slab'' and ''New obstruction''
« on: May 06, 2016, 10:01:47 am »

Hi all,

I'm modelling a heat transfer analysis of a concrete slab. The two commands ''New slab'' and ''New obstruction'' are very similar (define four and two points respectively). Is there any difference when using the two commands for modelling a slab under fire?

Thanks
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Jared

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Re: ''New slab'' and ''New obstruction''
« Reply #1 on: May 07, 2016, 08:12:04 pm »

Make one of each and then click the tab at the bottom of the screen which says, "Record View".  This will show you what the PyroSim inputs will look like for FDS.  You should see there that they are both input into FDS as simple obstructions.
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JLo

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Re: ''New slab'' and ''New obstruction''
« Reply #2 on: May 08, 2016, 02:24:57 pm »

Thanks for your reply. I've tried this before, then found that the "Record View" outputs are &OBST for both "new slab" and "new obstruction", that's why come up this question. The two commands are bit confusing as they seem very similar (almost same) in FDS. 
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Jared

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Re: ''New slab'' and ''New obstruction''
« Reply #3 on: May 13, 2016, 08:00:11 pm »

Right and that was the point - they are both treated the same in FDS.  The only difference in PyroSim is that an obstruction will give you Cartesian coordinates to determine the 3D size of the obstruction while a slab will allow you to determine a plane with a thickness.
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JLo

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Re: ''New slab'' and ''New obstruction''
« Reply #4 on: May 30, 2016, 04:49:45 am »

Thanks for your reply, Jared!
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mdangelmaier

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Re: ''New slab'' and ''New obstruction''
« Reply #5 on: June 30, 2016, 08:33:45 am »

In addition to that, I just had a minor issue using a slab obstruction. When I put a hole in it, smoke wouldn't get through.
It does however, when I use a thin obstruction.
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