Flammability of Plastics in Today's Automobiles 2015-01-1380

According to the National Fire Protection Agency (NFPA), from the most recent available data, it was estimated that there were 164,000 highway vehicle fires in 2013 causing roughly 300 civilian fire deaths, 925 civilian fire injuries and $1.1 billion in property damages [1]. In a modern automobile, the plastics content is dramatically higher than it was in 1972, when Federal Motor Vehicle Safety Standard (FMVSS) 302 was implemented [2]. FMVSS 302 applies only to materials in the passenger compartment and was put in place to address accidental fires started from sources such as cigarettes, matches, etc. There has never been any regulation for the plastic materials used outside the vehicle interior, including those used in under-the-hood (UTH) applications, and this is true even for today's automobiles. Combustible materials are roughly twice the weight and represent twice the heat content of the gasoline used in a typical passenger car today, constituting the major fire load [3]. In impact-survivable accidents, most frequently, plastic materials are the first to ignite; their ignition and continued burning are the major causes of death [3]. Increasing electronic content and the growth of electric and hybrid vehicles make material flammability even more critical [4]. Fire scientists have long recognized that FMVSS 302 is inadequate for interior materials in automobiles [5, 6, 7] and that there is a need for even stricter flammability regulations for UTH materials that are exposed to high heat and abuse [8].

The main objective of this paper is to address some of these concerns and provide additional information for what many have been advocating for a number of years [1,5, 6, 7, 8]. Several small scale tests like Limiting Oxygen Index, UL-94 and Cone Calorimetry were carried out, along with FMVSS 302, on representative plastic materials used in automobiles. Results from these studies are presented to show how one cannot rely on predicting the combustion behavior of these materials in a real fire and that significant improvements are needed to make today's and future automobiles safer.