Fire behavior of polymethylmethacrylate

Abstract

A comprehensive study on the flammability, flame spread, and flame extinction behaviors of polymethylmethacrylate slabs and cylinders is presented. These behaviors have been quantified simultaneously for the first time in the Factory Mutual Research Corporation's 50 kW-Scale Flammability Apparatus. All experimental data show good agreement with the literature. A new technique has been developed to calculate pyrolysis height and flame spread rate from chemical and convective heat release rates. The calculated flame spread rate conveniently provides more information than obtained from the conventional methods. Flame spread behavior is found to be accelerating for upward spread and nonaccelerating for downward spread. Flame spread rate increases with increase in the oxygen mass fraction. Surface regression rates for upward and downward flame spread are negligible compared to the flame spread rates. Flame height is proportional to the pyrolysis height to the 2 3 power; ratio of flame height to pyrolysis height is proportional to the Froude number to the 2 3 power, and the flame height is proportional to the 2 3 power of the chemical heat release rate, in agreement with the literature. The study suggests that it is possible to use conventional flammability apparatus to simultaneously determine flame spread rate, heat release rate, and generation rates of material vapors and chemical compounds. It is our hope that this study will generate further research interest and standardized test apparatus and procedures will be developed.