Thermogravimetric analysis and pyrolysis characterization of expanded–polystyrene and polyurethane–foam insulation materials

Abstract

Expanded polystyrene (EPS) and polyurethane foam (PUF) are commonly used as building insulation material for energy savings; however, the fire risk is high because insulation material ignites easily and combusts upon exposure to external heat sources. Insulation materials are regarded as solid fuels, which undergo pyrolysis before combustion. Therefore, elucidating insulation material pyrolysis is an important aspect of efforts to predict combustion and fire phenomenon in these materials. Thermogravimetric analysis (TGA) was conducted to investigate the pyrolysis behavior of EPS and PUF in a nitrogen atmosphere using four heating rates. The results showed that the pyrolysis of EPS and PUF in nitrogen occurred through one- and two-weight loss reactions, respectively. Based on the pyrolysis temperatures obtained via TGA, the effective activation energies were determined using multiple model-free methods. The pre-exponential factors were calculated by applying the kinetic compensation effect from the reaction mechanism established using the model-fitting method. Additionally, the material activation energies and pre-exponential factors determined from experiments could be used as pyrolysis properties for numerical predictions of fire using the Fire Dynamics Simulator (FDS). Numerical simulations were conducted to validate the material activation energies and pre-exponential factors determined from experiments based on the FDS pyrolysis model.