Glass fiber-reinforced intumescent flame-retardant systems in mild fire conditions—part 1: Cone calorimetry and modeling

This article presents a three-dimensional pyrolysis model that is capable of simultaneously predicting the back surface temperature profiles, the mass loss, and the heat release rate of an intumescent-based flame-retardant polymer composite. The model is based on mass and energy conservation, heat transfer equations in porous media, and a moving boundary condition (expansion rate) to mimic the thermal expansion of the intumescent material. The strength of this model lies in the extensive experimental effort to measure input parameters. These parameters were determined through microscale tests (thermogravimetric analysis, differential scanning calorimetry, pyrolysis combustion flow calorimetry, transient plane source, and parallel plate rheometry). A long glass-fiber reinforced flame-retardant polypropylene was employed as intumescent material to develop and to validate the model. Validation of the model done on cone calorimetry data showed that all curves were well captured (temperature/time curve, heat release rate, and mass loss rate).