Experimental study on hardening a motorcoach against tire fire penetration

Abstract

SummaryThree full‐scale fire experiments were conducted to assess methods of hardening the motorcoach against penetration of a tire fire. The first method was to replace the combustible fender and exterior side panel above the wheels with stainless steel sheet metal. The second method was to coat the plastic fender and side panel with an intumescent layer. The third method was to install a sheet steel fire plume deflector between the fender and side panel. A special burner was used that imitates the frictional heating of hub and wheel metal caused by failed axle bearings, locked brakes, or dragged blown tires. For each experiment, heating to obtain tire ignition was initiated on the exterior of the passenger side tag axle wheel. Measurements of interior and exterior temperatures, interior heat flux, and heat release rate were performed. Standard and infrared videos and still photographs were recorded. The experimental results were compared with those obtained with no fire hardening. The metal replacement method performed best and prevented fire penetration for over 30 min longer than the nonhardened cases. The intumescent coating extended fire penetration by about 20 min longer than the nonhardened cases. The steel plume deflector had no significant impact on the timing for fire penetration of the windows. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.