Pyrolysis in FDS

[cemilyc]

Hello,

I am trying to model polyurethane foam pyrolysis in FDS using the complex pyrolysis method described in Section 11.5 of the FDS User’s Guide.
i did not use the Foam predefined in the FDS library.
I do not have direct experimental values for the Arrhenius parameters A and E. Therefore, I used the FDS input option based on reference temperature, reference rate, and heating rate. These values were estimated from TGA information for polyurethane.

In the fire simulation, the surrounding polyurethane foam does not produce additional HRR, although it is exposed to the ignition source.

Could you please advise what I should check ?

Below are the relevant MATL input and the material information printed in the FDS output.

&MATL ID='FOAM',
FYI='Caution: Reaction',
SPECIFIC_HEAT=1.4,
CONDUCTIVITY=0.034,
DENSITY=22.0,
HEAT_OF_COMBUSTION=2.8E+4,
N_REACTIONS=1,
HEAT_OF_REACTION=1350.0,
SPEC_ID(1,1)='SFPE POLYURETHANE_GM37_fuel',
NU_SPEC(1,1)=1.0,
REFERENCE_TEMPERATURE=300.0,
REFERENCE_RATE(1)=0.002,
HEATING_RATE(1)=5 /

FDS output:

Material Information

1 FOAM

Emissivity: 0.900
Density (kg/m3): 22.0
Specific Heat (kJ/kg/K) Ambient, 293 K: 1.400E+00
Therm. Cond. (W/m/K) Ambient, 293 K: 3.400E-02

Reaction 1

Gaseous Yields:
SFPE POLYURETHANE_GM37_fuel: 1.000

A (1/s): 9.425E+13
E (J/mol): 1.782E+05
H_R (kJ/kg) TMP_REF, 573 K: 1.350E+03
N_S: 1.00
N_T: 0.00

Thank you very much for your help.