EVALUATION OF THE FIRE EXTINGUISHING EFFECTIVENESS OF SPRINKLERS IN FIRES OF SELECTED FLAMMABLE MATERIALS USING COMPUTER SIMULATION METHOD

<ns3:p>The main objective of this study was to analyse the feasibility of using PyroSim software to evaluate theextinguishing effectiveness of sprinklers in case of fires involving selected combustible materials, whichare often found in modern interiors, such as polyurethane and pinewood. To perform numericalcalculations, a geometric model of the computational domain, consisting of a selected room and itsfurnishings located at the Military University of Technology in Warsaw, was established. This modelwas parameterised and four thermocouples and two sprinklers were deployed. A numerical model ofthe combustion reaction of the selected combustible materials was also developed. This model was usedto conduct numerical analyses for two selected sprinkler models from The Viking Corporation, ModelM, and Grinnell, Model A. HRR fire rate curves, the total heat release curves, and the smoke distributionsat 10, 20, 40, and 60 seconds of the fire duration, as well as the room temperature curves at 10, 30, and60 second were obtained during simulation studies. Furthermore, also presented were the temperaturecurves recorded by the four thermocouples. Analyses of the obtained results enabled the assessment ofthe extinguishing effectiveness of the selected sprinklers and their impact on the combustion process ofselected materials, and thus on the development and spread of fire hazards such as smoke and thermalimpact. Based on the analysis, several conclusions have been formulated. It was found that bothsprinklers used did not provide complete control of smoke spread, and that the Grinnell sprinklers weremore effective in reducing temperature and overall heat release than the Viking sprinklers. Comparingthe total heat released after 60 seconds, the Grinnell sprinklers were found to be approximately 40%more efficient than the Viking sprinklers. This is further confirmed by the fact that the maximumtemperature recorded by thermocouple No. 1 was approximately 120C lower during polyurethanecombustion and approximately 150C lower during pine wood combustion for the Grinnell sprinklers.This results from their faster activation due to their lower temperature threshold (57C for the Grinnelland 68C for the Viking) and the activation of two sprinklers rather than one within the assumedsimulation window. Therefore, it is recommended to use the Grinnell model in situations requiringrapid and effective temperature control.</ns3:p>