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.130-1.01.96).Various polymeric materials must be analysed on toxicity of burning products in accordance with the Trade Standard of Ukraine ГСТУ 12.11.402-97 "Substances, materials and articles for coal mines.Methods of determination of fire hazard".Publications of last years give much attention to correctness of selection of materials used in conveyor transport, disregarding at the same time other materials being lowered into the mine (cable sheaths, vent tubes, glass cloth laggings, stoppings, fire-protective coatings of wooden constructions, etc.) from the point of view of the degree of their fire hazard.In view of toughening the fire safety requirements in the coal industry conveyor belts are certificated apropos of fire hazard that includes analysis of volatile matters of burning and thermal destruction in addition to estimation of the combustibility parameters.As a result of the investigations that have been carried out one can ascertain formation of contents of harmful substances in air of the mine working in a number of cases exceeding the MAC values under accident conditions even by thermal destruction of some meters of the belt.Quantitative information about potential toxic hazard of the conveyor belts can be one of the criteria for selection of the belt by a user.Besides the toxic hazard formation of considerable amounts of CO, hydrogen sulphide and other combustible gases at the initial stage of the fire can promote flame propagation and make worse the fire hazard parameters.Shorting in cables and contact conductors is one of the typical causes of the origin of open fires.Preliminary estimation of formation of harmful substances by burning and thermal destruction of the cable sheaths allows to forecast the degree of toxic hazard under accident conditions.The tested specimen of the polyvinylchloride cable sheath isolates 48.8 g/kg CO, 198 g/kg HCl (Figure 2) by thermal destruction.Due prominence isn't given to the problem of the dangerous use of vent tubes in mines from the point of view of active isolation of toxic gaseous products by them when heating already up to 250oC.At the initial stage of the fire the flexible and rigid vent tubes isolate in considerable quantities such toxic gases as carbon oxide, hydrogen cyanide, hydrogen chloride, formaldehyde, phenol, phosgene which can influence change of the gas situation in the working to a marked degree.By thermal destruction of the specimen of the polyvinylchloride vent tube 56.7 g/kg CO and 85.1 g/kg HCl (Figure 2) isolate.Products of thermal decay of some types of the roll glass cloth laggings contain a number of toxic compounds composition of which depends on properties of impregnation mixtures, too.The tested specimen of the fabric with one-sided impregnation isolates 21 g/kg CO and 30 g/kg HCl (Figure 2).It is obvious that fracture of total mass of harmful substances forming by burning these materials is comparable with quantity of toxic components in burning products of the conveyor belts.Figure 2.Fracture of total mass (G) of hydrogen chloride and carbon oxide by thermal destruction of material specimens: 1 - cable sheath; 2 - vent tube; 3 - glass fabric; 4 - conveyor beltThe adduced results as well as experimental data on other toxic components of the gas mixture allow to forecast the total contents of each harmful substance at the mine working at the initial stage of the fire.Thus, heating the articles made from polymeric materials by underground fires is accompanied by their thermal destruction with possible generation of gaseous combustible and toxic products in the environment.Proceeding from the data concerning quantity and types of harmful substances isolating from various materials under accident conditions and taking into account the total influence of toxic substances, one can lower possible damage to health and life of working people.It is necessary to prevent grave consequences by selection of materials with optimum properties, rate setting the quantity of materials exposed to burning and being placed in the unit of volume of the working at the same time, or by determination of proper ventilation conditions.The conducted investigations must be taken into account by selection of individual protection means for mine workers and mine rescuers as well by selection of methods and means for elimination of accidents bound up with burning the conveyor belts and other mine materials.REFERENCESГОСТ 12.1.044-89 ССБТ.Пожаровзрывоопасность веществ и материалов.Номенклатура показателей и методы их определенияГСТУ 12.11.402-97.Речовини, матеріали та вироби для вугільних шахт.Методи визначення пожежної небезпекиДНАОП 1.130-1.01.96, 1996, Правила безопасности для угольных шахт: Утв.Госкомитетом Украины по надзору за охраной труда от 18.01.96 г., № 7.Основа, КиевИличкин, В.С., 1993, Токсичность продуктов горения полимерных материалов.Принципы и методы определения.Химия, Санкт-Петербург2I SZKOŁA AEROLOGII GÓRNICZEJ 19995876PROCEEDINGS OF THE 7TH INTERNATIONAL MINE VENTILATION CONGRESS877PROGNOSIS AND PREVENTION OF EMERGENCY SITUATIONS BOUND UP
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