Characterization of the fire behaviour of an exterior insulation system at intermediate scale. Application to a high-pressure laminate (HPL) claddings

This paper presents the experimental results of intermediate-scale tests related to the fire behaviour of highpressure laminate (HPL). The experiments correspond to a cladding submitted to an exterior fire, to study its thermal decomposition and burning behaviour when exposed to two heat fluxes: 30 kW m- 2 and 60 kW m- 2. Measurements of mass loss, mass loss rate (MLR), gaseous emissions, heat release rate (HRR), temperatures and position of the thermal decomposition front have been performed for two sample sizes of 50 x 50 cm2 and 100 x 100 cm2. Considering the mass loss, the MLR, the HRR and the temperatures, 3 stages have been identified during the fire development of the samples. The first one corresponds to the heating phase of the sample, the mass loss and gaseous emissions are almost null. However, the measurements of the thermal decomposition fronts highlight that this first stage of fire development can be divided into two phases: an initial phase where the front is spreading and a secondary phase where it remains constant. The second step corresponds to the inflammation of the sample. During this stage, temperatures reached 1000 degrees C in the air cavity and the heat fluxes on the upper part of the sample reached between 50 and 70 kW m- 2. The last one corresponds to the extinction.