The severe bus fire in November 2008 in Germany (near Hannover) with over 20 fatalities arose again theworries that fire safety levels of bus materials do not fulfill the requirements of Directive 95/28/EC of theEuropean Parliament and of the Council (relating to the burning behaviour of materials used in the interiorconstruction of certain categories of motor vehicles), to prevent the development of a fire in the passengercompartment or to delay the fire development long enough that passengers could leave the bus in the caseof fire.The current fire tests materials used in bus interiors do not live up to that requirement. Only small ignitionsources are taken into account. The recent accident and other investigations show that electrical faults orfuel leaks are considerably bigger ignition sources which lead to rapid fire and smoke spread into andthrough the passenger compartment.The cause of the fire in the German bus accident was an electrical failure in the kitchen area of the buswhich led to a hidden fire in the bus toilet. After the toilet door was opened by a passenger the fire spreadvery rapidly through the bus and most of the passengers could not escape. The authors have numericallymodeled the spread of fire and smoke of this incident. The results show the very rapid fire spread throughthe cabin and the blocked rear exit.In addition to the numerical calculations small and intermediate scale tests of foam materials and seatmock-ups were performed. Bus materials and train materials were compared. The heat and smoke releaserates were measured under well-ventilated conditions in a calorimeter and the materials were tested undervitiated conditions in the smoke density chamber. The smoke production and the smoke components weremeasured under under-ventilated conditions. The test results show clearly the benefit of the higher firesafety standards in trains, i.e. the train materials are less flammable and release less heat and smoke.These data were used to perform further numerical calculations to compare different scenarios under theassumption that train material would have been used in a bus. Clear benefits for the fire safety in busescould be demonstrated.
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