Demonstration of the effect of softening and fire resistance of materials on burning characteristics

Abstract

AbstractAn important observation during full‐scale fires was that burning behaviour is often determined by softening characteristics as well as ignitability, flame spread, etc. Examples include stacking chairs where thermoplastics give a rapid rate of fire growth and suspended ceilings where thermoplastics reduce fire hazard. A test rig has been progressively developed at RAPRA to reproduce the mechanisms and fire growth rates of stacked chairs and to evaluate the role of softening in fire growth. Although the ignitability of fire‐retarded materials is less than that of non‐fire‐retarded grades, the fire growth rate in stacks is similar and may be related to the softening behaviour determined by exposing sheets of material to radiant heat. The rate of fire growth in stacks may be significantly reduced by modifying the softening behaviour of materials, e.g. by using asbestos‐reinforced thermoplastics which can form an integral, non‐melting felt or by using non‐melting materials such as SMC or wood.