Thunderhead Engineering Forum

Public Forum => PyroSim => Topic started by: Nitzan Hirsh on April 06, 2014, 06:32:12 am

Title: aggressive smoke developement
Post by: Nitzan Hirsh on April 06, 2014, 06:32:12 am
Hi,
I've seen that in various models the smoke developement was rapid in comparition to NFPA equations  - even with usage of sprinklers / limiting HRR / lowering soot yield.
any ideas about a hidden parameter that controls smoke developement?

My defaults are usually furniture fires, that include -
t-squared HRR, 500-3000 KW, average/fast.
standard polyurethane reaction, with heat of combustion - 17600 kj/kg and soot yield of 0.07.

Thanks!





Title: Re: aggressive smoke developement
Post by: Charlie Thornton on April 11, 2014, 08:24:03 am
I'm not familiar with the NFPA model. Is there a test scenario that predicts the smoke layer height over time? How big of a difference are you seeing?
Title: Re: aggressive smoke developement
Post by: Dave McGill on April 28, 2014, 03:27:33 pm
Nitzan,

The SFPE Handbook 3rd, Table 3-4.14 lists the soot yields for 4 different flexible polyurethane foams. The average of the values is 0.19 g/g. That is almost 3 x the value you use.

Dave