Field testing and extinguishing efficiency comparison of the optimized for higher expansion rates deflector type sprinkler with other foam and foam-water sprinklers

Abstract

The process of foam formation in sprinklers (nozzles) for automatic extinguishing systems at present is poorly studied. There are no analytical models for predicting this process due to the presence of many complex physicochemical, mechanical and other phenomena. Previously, the authors studied the influence of the geometric parameters of the sprinkler (the frame arms and deflector) on the foam expansion rate K. The sprinkler with optimal geometry (the OFS sprinkler) capable to generate foam with expansion rate K of 13.6 was developed. In this work, the OFS sprinkler was tested under conditions close to a real fire. The comparison of the extinguishing efficiency of the OFS sprinkler with three deflector type sprinklers widely used in automatic foam extinguishing systems is presented. Fire extinguishing efficiency of the tested sprinklers was compared by using the extinguishing efficiency indicator Et, which takes into account the extinguishing time of the model fire site and specific discharge of the extinguishing agent. It was found that the fire extinguishing efficiency of the OFS sprinkler is more than 2.5 times better compared with the other tested sprinklers.