An experimental and numerical study on fire behaviors of charring materials frequently used in buildings

The single biggest market barriers of building materials is their fire risks, suffering from easily burning and generating a large amount of smoke and toxic gases. Fire behaviors of typical charring materials, including timber (Cherry) and polymer (acrylonitrile butadiene styrene, ABS), were investigated both experimentally and numerically. The proposed numerical model has considered both solid (the area inside sample slab) and gas (the area above sample surface) phases, addressing some previously usually-ignored fire processes, such as water evaporation, gases and liquids transportation inside solids, and volume change. Numerical results of timber and polymer were validated by cone calorimeter experiments. From both experimental and numerical results, three different stages of mass loss rate histories of charring materials were observed under external heat flux. In the gas phase, three high temperature areas were observed: two are near the walls of the two heaters due to the convection heat transfer; and one represents diffusion flame above sample surface, in which temperature increases with the intensity of external heat flux. This study provides not only an attempt to combine both solid and gas phases modeling for building materials, but also a platform for fire behavior modeling. Future research will focus on the validation of gas phase modeling and implementation of flame radiation.