Aircraft Blanket Ignition and Toxic Emission in Simulated Aircraft Cabin Fires Using the Cone Calorimeter
The toxicity and flammability of aircraft cabin blankets was investigated, using a controlled atmosphere cone calorimeter with a compartment around the test specimen which was used for controlled fire ventilation. A calibrated heated FTIR was used to analyse the toxic gases from the raw fire product gas using a heated gas sampling system. The blankets were tested at a heat flux representative of a developed fire and in a ventilation controlled atmosphere at 15 air changes an hour or 20 g/m2s, typical of that found in an aircraft passenger cabins. The FTIR was calibrated for the analysis of 65 species including all the significant toxic emissions. Six different aircraft blankets were investigated and three that had significantly different compositions were fire tested and these included fire retarded and non-fire retarded blankets. Vertical fire propagation was also investigated. Two phases of burning were observed, flaming and smoldering combustion. The highest toxicity was during the flaming phase, but during the smoldering phase there were high concentrations of irritant gases. HCN was the most dominant toxic gas for the two high fuel bound nitrogen blankets and acrolein for the low fuel bound nitrogen specimen blanket. There was evidence of HCl from halogenated flame retardants in the smoldering period. The controlled atmosphere cone calorimeter was shown to be a good method for testing materials for their toxic gas production under realistic ventilation controlled compartment fire conditions. It was recommended that materials that could be part of fire initiation in aircraft cabins or elsewhere, should be subject to fire tests that access toxicity levels at realistic fire ventilation conditions. This work shows that some fire blankets could be eliminated from use if test procedures reflected their toxic gas yields, rather than just their fire propagation and smoke production rates, which is the basis of current aircraft fire material tests.
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