At present the most efficient fire extinguishers are power ones. Fireextinguishing powders of serial production do not fulfill modern requirements, primarily from the viewpoint of their universal and practical use. It must be noted that most of them contain halogen, and it is established that penetration of halogens into the atmosphere causes a breaking of the ozone layer. The main goal of investigation presented in this paper is development of non-halogen, non toxic, environmentally-friendly, highly-efficient, inexpensive, universal, composite fire-extinguish powders based on domestic mineral raw materials such as clay shale, zeolite and perlite. The proposed method of obtaining composite powders does not require the following expensive chemical processing and modification with halogen-inclusive hydrofobizative additives. Hence, these composite powders will be cheaper (1,5-2 times) than powders of serial production. The raw materials: clay shale, zeolite, perlite were selected according to high operating properties, which are indicative of a reduction of burning processes. The powders must not only be effective during the fire extinguish, but also they must maintain those properties, which decrease the extinguishing effect after small changes in properties. The effectiveness of powders is defined not only according to their dispersity and inhibition ability, but also according to their storage and transportation conditions. These conditions are defined by the exploitation properties of powders. The most important among them are: consolidation and caking, dispersity, tendency of humidity, flow and storage duration. We studied the performance properties of zeolite, perlite and clay shale and composite powders based on such materials and established dependence of tendency to consolidation and caking on dispersity. Accordingly, the dispersity of composite powders was selected in such a way that the tendency of consolidation and caking was minimal. At the same time particle size should be relevant towards the rapid head and destruction, so that we have a homogenous effect and heterogeneous inhibition.
The aim of the presented investigation is the development of technology for production of novel, halogen-free, environmentally safe, highly efficient fire-extinguishing powders based on local mineral raw materials, which does not require modification with expensive, halogen-inclusive, hydrofobizing additives, providing low-cost production of fire-extinguishing powders in comparison with imported analogues. The optimal dispersity was selected in such way, that caking capacity be minimal and a homogeneous action of combustion products on the flame as well as a heterogeneous inhibition of combustion process must take place. The evaluation of powder efficiency is carried out with consideration of the both effects. Experimental data confirm that the developed fire-extinguishing powders are characterized with high performance characteristics, as well as high fire-extinguishing capacity. At the same time, it should be noted, that the efficiency of the obtained powders is practically the same as of standard imported powders, but do not contain any halogens, is environmentally safe and 1.5-2 times cheaper than the imported analogues. For obtained powders, the conditions of extinguish optimum and effective use of powder are stated. Optimum extinguishing condition means the selection of optimum intensity of powder supply into seat of fire when minimum consumption of powder provides fire extinguishing in minimum time. Thus, in order to determine optimum conditions of extinguishing it is necessary to study the dependence of powder specific consumption and extinguishing time to supply intensity. For our powders optimum condition of extinguish is: powder supply intensity I-0.6-1.0 kg/m 2 sec to fire center when powder specific consumption does not exceed G=0.8-1.2 kg/m 2. Therefore, we can assume that the use of fire-extinguishing powders of our preparation is possible at extinguishing all types of fires over ground, as well as, underground constructions and does not need additional antiseptic measures.
The aim of the presented investigation is the elaboration of non-halogen, nontoxic, ecologically sound, high-efficient, universal, composite fire extinguishing powders on the basis of domestic mineral raw materials which satisfy the following requirements: -are characterized with high performance properties and fire extinguishing ability; -are used for extinguishing of all classes of fires; -are used for extinguishing of large-scale fires, forest fires and at the same time provide the enrichment of burnt out soils with different necessary salts; -are used in large temperature range, as well as at such low temperatures when CO 2 , water and foam cannot be used; -at extinguishing will make heterogenic as well as homogeneous inhibition of burning process.
The aim of the presented investigation is the development of the novel halogen free, environmentally safe and highly efficient universal (working on several classes of fires) fire-extinguishing powders on the basis of local mineral raw materials. The technology for production of these powders differs from the convenient production technology, is much simpler and significantly cheaper. Powders will be produced by mechanical milling of local mineral raw materials, which do not require modification with expensive halogen-containing hydrofobizing additives, making the extinguishing materials far cheaper than imported analogues. Optimal dispersity of powders was selected to provide the minimal caking capacity, a homogeneous action of combustion products on the flame and a heterogeneous inhibition of combustion process. The evaluation of powder efficiency was carried out considering the both effects. For a comprehensive evaluation of the extinguishing effect two special characteristics were selected: the reciprocal value of extinguishing "surface" concentration ("surface" concentration means a total surface area of powder particles in a unit volume) and the coefficient of recombination of atomic oxygen on the surface of solid particles (measured using Electro Paramagnetic Resonance (EPR) methods). In order to evaluate the fire-extinguishing ability of powders, the "polygon testing" methods are used, which consider extinguishing of different class of standard fires with the help of standard fire-extinguishing constructions. Experimental data confirm that the developed fire-extinguishing powders are characterized with high performance characteristics, as well as high fire-extinguishing capacity. At the same time, it should be noted, that the efficiency of the obtained powders is practically the same as of standard imported powders, but do not contain any halogens, is environmentally safe and 1.5-2 times cheaper than the imported analogues.
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