A quantitative understanding of the processes that take place in the condensed phase of a burning material is critical for prediction of ignition and growth of fires. In the current study, a model of burning of two widely-used charring and intumescing polymers, bisphenol A polycarbonate and poly(vinyl chloride), was developed and validated. The modeling was performed using a flexible computational framework called ThermaKin, which had been developed in our laboratory. ThermaKin solves time-resolved energy and mass conservation equations describing a one-dimensional material object subjected to external heat. Most of the model parameters were obtained from direct property measurements. The model was validated against the results of cone calorimetry experiments performed under a broad range of conditions. Potential sources of uncertainties in the model parameterization were analyzed. (C) 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.