Fire contributes to aircraft accidents and many fatalities. The growing use of polymer composite materials in aircraft has the potential to increase the fire hazard due to the flammable nature of the organic matrix.
The polymer composite most often used in the external structures of aircraft is carbon/epoxy, which is a flammable material that easily ignites and burns when exposed to fire. A large percentage of the cabin interior of wide-bodied passenger aircraft is made using composite materials, mostly glass/phenolic. Phenolic composites have good flammability, but newer materials are being developed that offer the promise of increasing the fire safety of aircraft cabins. In fact, a large number of new composite materials are being developed for cabins and external structures that have the potential to increase the fire safety of aircraft, but a detailed analysis of the fire performance of these materials against conventional materials now used in aircraft has not been performed. Such an evaluation will provide a clear indication of the potential improvements in fire safety by using new fire resistant composites in aircraft.
This report assesses the fire hazard of current and next-generation polymer composites for aircraft, and identifies those materials with improved flammability resistance. A comprehensive review of the scientific literature was performed to develop a database on the fire properties of a large number of polymer composite materials. For both aircraft cabin materials and aircraft structural materials the following fire properties were considered in the determination of fire safety: time-to-ignition, limiting oxygen index, peak heat release rate, average heat release rate, total heat release, flame spread rate, smoke, and combustion gases. The data is presented as performance tables which rank the composite materials in order from best to worst.
The composite most often used in pressurised aircraft cabins is glass/phenolic, and the database shows that this material has excellent fire reaction performance1 and that very few next-generation composites display superior properties. The most used structural composite is carbon/epoxy, and this material has poor fire resistance and can pose a serious fire hazard. A number of advanced structural composites with superior fire properties are identified, including materials with high temperature thermoset polymer, thermoplastic or inorganic polymer matrices.
- Fire reaction performance is a measure of a material's resistance to combustion as determined by a range of parameters such as time-to-ignition, heat release rates, limiting oxygen index, etc.