Necessity of testing fire behaviour of plastic materials under flashover

Abstract

With so many arson fires reported recently, contribution to heat in burning the combustibles in a flashover room fire should be better understood. This suggests that it is necessary to study how materials are burnt under flashover. Three selected plastics samples of polyvinyl chloride (PVC), polycarbonate (PC) and polymethyl methacrylate (PMMA) were tested in this paper. Heat release rate, the most important parameter in fire hazard assessment, was measured. The three plastics samples were assessed by two scenarios: an accidental fire and an arson fire giving flashover. Full-scale burning tests were carried out in China in a room calorimeter of size similar to that of ISO 9705. A total number of five tests were carried out to measure the heat release rate. The net heat release rates in burning the plastics were measured. Results indicated that PMMA would be burnt completely under an accidental fire. PVC and PC were difficult to ignite with low heat release rate in a growing fire. However, under an arson fire to give flashover, PVC and PC burnt vigorously with much more heat given out. All the results support the necessity of testing plastics under flashover fire conditions.