The Effective Parameters for Reaction-to-fire Properties of Expanded Polystyrene Foams in Bench Scale

Fire behaviour of different types of expanded polystyrene (EPS) was studied with the use of ISO 5660 cone calorimeter test method. The roles played by specimen density and thickness on fire performance of the foam were examined. The relationship between the fire properties of specimens, such as total-heat-release and heat-release-rate, with their densities and thicknesses was determined. The thickness of specimens played two contradictory roles on fire behaviour of specimens. On the one hand, due to rapid melting the specimen received less heat energy relative to the calibrated level and hence the ignition was delayed. On the other hand, the available mass for combustion reactions increased, which resulted in higher heat and smoke release (both total and rates). This should be carefully considered in interpretation of fire test results of EPS foam in predicting its fire risk. It was revealed that both average and the peak-of-heat-release-rates were directly dependent on density of the foam and increased with it. A good repeatability for heat-release-rate was obtained in this method, but this was not held for ignitability of specimens. The results showed that time-to-ignition cannot be a characteristic value to make distinction between the standard and fire retarded types of EPS in cone calorimeter test, but peak-heatrelease- rate values can be well utilized for this purpose.