Fire tests on coverings with a substrate of cellular plastics

The report contains results from various small scale fire tests carried out on typical coverings on a substrate of cellular plastic materials. The ordinary testing of coverings is presently done on a substrate of particle board, but the results obtained here show that the fire protection time obtained in these tests may not always be applicable to other substrates. For the same covering the fire protection time may vary by a factor of almost 10 depending on the substrate. The report also states that a temperature of 190 °C is considered to be a safe critical surface temperature for a substrate of polyurethane and 100 °C for a substrate of polystyrene. The critical temperatures for substrates can be determined accurately with both an ignitability apparatus in accordance with ISO 5657 or a cone calorimeter, both operated at a heat flux level of 30 kW/m2. The results also showed that one must also take into consideration the interaction between the covering and the substrate and not base classification only on the deterioration temperature of the polymeric substrates. It was particularly noticed that humidity from water containing covering materials causes strong deformations of substrates of cellular plastics.