SCHOOL BUS FIRE TESTING: NEW ASTM SEATING STANDARD

摘要

In the US there are very few mandatory reaction-to-fire requirements for highway vehicles,rnincluding cars, buses and school buses. In fact, the only mandatory reaction-to-fire requirement is therninfamous FMVSS 302 flame spread test, in place since the late 1960s, which applies to “any portionrnof a single or composite material which is within 13 mm of the occupant compartment air space” ofrnall “passenger cars, multipurpose passenger vehicles, trucks, and buses”.rnThe National Conference on School Transportation adopted, in the 1980s, a fire test for school busrnseating, based on igniting a paper bag filled with newspaper placed above and beneath a school busrnseat assembly (paper bag test). ASTM fire standards committee members believed that a paper bagrnwas not a reliable source of ignition. This test is used by many US and Canadian school busrnauthorities for assessments of school bus seating flammability but it is not included in federalrnregulations.rnIn 2011 ASTM completed the development of a new, more reliable, fire test. The test requires that arnschool bus seat assembly (3 seats) be exposed to flames from two gas burners. One gas burner (whichrnis identical to the burner used for room-corner tests) exposes the seat assembly from underneath thernseats and another one (which includes the same burner as used in CA TB 133, but with a differentrnhandle) exposes the seats from above. The test assesses: (a) whether flame spreads from the exposedrnseat assembly to others in the school bus, (b) how long flaming lasts and (c) how much of therncombustible weight of the seat assembly is lost. As usual with most ASTM standards, the standardrndoes not contain pass/fail criteria but the non-mandatory appendix shows the criteria used by thernpaper bag test.rnThe new ASTM standard test is designated ASTM E2574, Standard Test Method for Fire Testing ofrnSchool Bus Seat Assemblies.