Fire behaviour of a Carbon/Nomex honeycomb sandwich composite used in aircraft interiors as ceiling panel

Abstract Fire behaviour of a carbon/Nomex honeycomb composite, used as ceiling panel in aircraft cabins, has been investigated experimentally. The thermal decomposition that was examined in a thermogravimetric analyser (TGA), under inert atmosphere, at several heating rates (5,10 and 20 °C/min), revealed a complex degradation process with overlapping stages. Cone Calorimeter tests at different incident heat fluxes, ranging from 20 to 70 kW/m 2 have also been performed. The material exhibited good fire performance with relatively low amount of heat release and long ignition times. Ignition did not occur at 20 and 30 kW/m 2 . Combustion of the material at 40 kW/m 2 proceeded in one stage, while at higher heat fluxes two stages were observed. The burning mechanisms and structural changes during thermal decomposition at different heat fluxes were also examined. The long tail after flameout in heat release curves and the significant increase in CO production and mass loss were analysed with respect to smouldering combustion of the material core. Measurements of the surface temperature prior to ignition were in agreement with the degradation processes observed in the TGA, and were also employed for the determination of ignition temperature (T ig = 593 °C). A modified iterative method, based on the correlation of the ignition data with the imposed heat flux, was adopted for the determination of the ignition parameters, including critical heat flux and temperature for ignition, providing results in agreement with experimental observations.