Fire behavior and mist suppression of a room lined with glass reinforced polymer (GRP) panels

Six water mist suppression experiments were conducted in an ISO 9705 size room lined with GRP panels with a small wooden crib as a fire initiation source. A four-nozzle water mist suppression system was used to extinguish the fires. Heat release rate (HRR) from the fires was measured, as well as: room temperature; wall surface temperature of GRP panels, and; heat flux to the wall at specific locations within the room. The concentration of oxygen, carbon monoxide and carbon dioxide was also measured in one corner of the room. It was found that the mist suppression method used was an effective system for extinguishing fires from 500 kW - 1.5 MW in magnitude. However, in one experiment in which only a single, centrally located nozzle was used the fire could not be completely extinguished. The GRP material was characterised using thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and cone calorimetry. The TGA results showed that the resin component of the GRP underwent pyrolysis over a temperature range of 225 °C to 450 °C when most of the resin mass was gasified leaving a solid char. The char material was completely consumed over a temperature range of 375 °C to 430 °C when heated in air. The DSC showed that, when heated in air, these two degradation steps released large amounts of energy. Cone calorimetry tests were conducted to measure the combustion behavior of the panel material (e.g. heat release rate (HRR) and time to ignition) when subjected to a constant incident radiant heat flux. The results showed that the panel material was flammable with a peak HRR of between 350-400 kW/m2 and the minimum heat flux for ignition was determined to be 16.5 kW/m2.