EFFECT OF FIRE OBSTRUCT FOR ASSESSMENT OF FIRE EXTINGUISHING ABILITY OF POWDER STRUCTURES

Experimental dependences of the specific consumption of extinguishing powder, and also the time of suppression of gasoline, diesel fuel and mix of gasoline and diesel fuel from the powder flow rate received during tests with specially created installation are given. The original methodology of experiment is presented. The sequence of experimental processes is given. During extinguishing it was detected concurrent effect — entrainment of atmospheric oxygen by disperse stream of powder in combustion zone, accompanying the main action of fire extinguishing substance—removal of heat from combustion zone. It is shown that the high efficiency of action of powder disperse stream is explained by high specific surface area of a disperse system. It is detected that additional mechanism of impact on a fire, attributed to powders, is the flame arresting effect. Quantitative ratios for estimation of the powder specific consumption and the time of suppression of combustible liquid flame are given. The analysis of these ratios indicates the presence of a minimal dependence of the specific consumption from the powder flow rate that is in satisfactory agreement with experimental results.