# Polyisocyanurate Foam Pyrolysis and Flame Spread Modeling
## 4 Conclusions  
The flammability of a PIR insulation foam product, manufactured by DuPont de Nemours Inc. and sold under the trademark Tuff-R [33], was analyzed in the current study through experiments and modeling performed on a wide array of sample sizes ranging in mass between a few milligrams and a kilogram. A complete pyrolysis property set was developed for this material; this set is summarized in Table 1 through Table 4. The pyrolysis property set was shown to accurately predict the outcomes of TGA, DSC, and MCC tests conducted on mg-sized samples at a range of heating rates, CAPA II and cone calorimetry tests performed on gram-sized samples at a range of heat flux settings, and vertical corner flame spread tests performed on entire insulation panels. The only non-standard instrument used for the pyrolysis property determination was CAPA II, but similar measurements can be performed in a standard instrument such as the Fire Propagation Apparatus (FPA) [44].  
Figure 9: A comparison of the mean experimental heat release rate obtained in the vertical corner flame spread experiments for the Tuff-R panels without facers with the modeling results using pyrolysis models without and with the blowing agent component.  
It was determined that a gaseous blowing agent stored in the foam cells contributed significantly to the foam burning rate and had to be accounted for in fire simulations. To accurately parameterize the contribution of the blowing agent to the foam flammability, cone calorimetry experiments on thick (2.54 \(\times\) 10\({}^{-2}\) m) foam samples, which retained the blowing agent during sample preparation, were required.  
A previously developed semi-empirical model [32] was used to simulate flame spread on the insulation panels in a vertical corner configuration, similar to SBI test. This model consisted of a detailed pyrolysis model (parameterized using the aforementioned milligram-scale and gram-scale experiments) coupled with a scenario-specific, spatially-resolved relationship between the total heat release rate and heat feedback from the flame to the pyrolyzing solid derived from the measurements of flame spread on PMMA. This model was found to perform well, indicating that it can be extended, without any modifications, to other materials.  
Conceptualization, S.I.S., M.W.B., K.A.S.; methodology, S.I.S.; software, D.M.C. and S.I.S.; validation, D.M.C. and S.I.S.; formal analysis, D.M.C. and S.I.S.; investigation, D.M.C. and S.I.S.; resources, S.I.S.; data curation, D.M.C.; writing--original draft preparation, D.M.C.; writing--review and editing, all authors; visualization, D.M.C.; supervision, S.I.S., M.W.B., K.A.S.; project administration, S.I.S.; funding acquisition, S.I.S., M.W.B., K.A.S. All authors have read and agreed to the published version of the manuscript.  
This research was funded by DuPont De Nemours Inc.  
Not applicable.  
The data presented in this study are available upon request. Please send your requests to the corresponding author.  
The authors would like to thank DuPont De Nemours Inc. for funding and [PERSON] for assisting with the CAPA II and full-scale experiments.  
The authors declare no conflict of interest.