Introduction. Using air-filled foam to contain and liquidate the flaming combustion of liquefied natural gas spills is one of the most optimal methods of preventing the escalation of emergencies. However, the amount of data available today is insufficient to standardize the basic parameters of air-filled foam injection.The purpose of this research project is to justify the application of air-filled foam to contain and liquidate the flaming combustion of liquefied natural gas and identify the basic parameters of injection. The following objectives are to be attained towards this end:  assessment of the fire and explosion safety of liquefied natural gas and analysis of extinguishing means applicable to spills;  experimental determination of the insulating ability of foams, having different expansion factors, if applied to the surface of cryogenic fluid;  experimental determination of the fire-fighting efficiency of the foam used to liquidate the flaming combustion of liquefied natural gas;  experimental verification of expediency of the joint application of high expansion air-filled foam and extinguishing powders.Results and discussion. Having discussed the findings of the in-house experiments and analyzed the international and domestic tests conducted for this purpose, the authors assume that the application of the foam, whose expansion factor equals 300 to 500 units, can effectively contain and liquidate the flaming combustion of liquefied natural gas. The flaming combustion cannot be liquidated, if lower expansion factor foams are applied. The application rate of the high-expansion air-filled foam, exceeding 0.08 kg/(m2·s), is required to reduce the intensity of flaming combustion. Flaming combustion can be efficiently liquidated if the application rate of high-expansion air-filled foam is set at 0.17 ± 0.01 kg/(m2·s). Fire-extinguishing powders can only be efficiently applied to liquidate the flaming combustion of liquefied natural gas, if its surface is covered in foam.Conclusions. The authors have used their in-house experimental data, analyzed the literary sources and wellknown properties of the fire-extinguishing foam to justify the basic parameters of foam application aimed at the containment and liquidation of the flaming combustion of liquefied natural gas.

Purpose. The relevance of creating a technology for containing and eliminating flame combustion of a liquefied natural gas (LNG) is beyond doubt. The use of foam fire extinction is one of the most promising options for creating such a technology. The purpose of the publication is to assess the possibilities of using air-mechanical foam to contain and eliminate the flame combustion of LNG, as well as to assess the prospects for scientific research in this direction. Methods. A review of regulatory documents that establish requirements for LNG and foam concentrates for extinguishing fires in of the Russian Federation was carried out. Methods for determining fire-extinguishing efficiency of foam were analyzed. The results of our own experiments, as well as international and domestic experience in conducting such studies are discussed. Findings. Based on the analysis of literary sources and the results of our own experimental studies the prospects for scientific research in the direction of extinguishing fires of LNG by foam are formulated. It is argued that in order to сontain and eliminate LNG flame combustion it is necessary to use high-expansion foam whose fire-extinguishing efficiency will also depend on the characteristics totality of a specialized foam concentrate and the characteristics of the LNG spill surface. Research application field. Further studies of air-mechanical foam properties for сontaining and eliminating flame combustion of LNG are promising. The composition of the foam concentrate used plays a key role in the foam effectiveness in preventing combustible vapors and gases from entering the combustion zone. The area of the research should also include solving practical problems on determining the foam expansion ratio and determining the normative intensity of foam supply, depending on which surface LNG spill occurred. Conclusions. The analysis of the obtained results made it possible to formulate promising areas of scientific researches on the use of air-mechanical foam for containing and eliminating LNG flame combustion, among which are the following: – developing formulations of specialized foam concentrates for extinguishing LNG fires; – searching options of foam use to control LNG burn-up; – determining the environmental conditions influence on the effectiveness of foam fire extinguishing LNG spills; – developing methods for determining foam concentrates quality for extinguishing LNG fires, and others.

No abstract

PURPOSE. The article studies the issue of extinguishing live electrical equipment by means of automatic fire suppression systems (AFSS). The purpose of the work is to assess the possibility of personnel’s safe use of various types of automatic fire suppression systems when extinguishing live electrical equipment at power facilities. The authors analyze the statistics of transformer substation and cable duct fires in the Russian Federation within the period from 2018 to 2021 and regulations in the field of application of automatic fire suppression systems for extinguishing fires of live electrical equipment. A series of experiments was carried out to determine the leakage current when a fire extinguishing agent is supplied from AFSS to energized equipment. METHODS. To study the possibility of using AFSS in case of fires of live electrical equipment at power facilities, methods of analysis and experiment are used. FINDINGS. The first series of experiments was carried out on an automatic gas fire suppression system using halon 125 as a fire extinguishing agent. Extinction of B1 simulated fire sources filled with n-heptane was carried out. Over the whole experiment on the hand-operated starting device of the automatic system leakage current did not exceed the threshold non-perceptible value of 0.5 mA. The second series of experiments was carried out on a water spray automatic fire suppression system. The large spray angle of the nozzles prevented the entire amount of fire extinguishing agent from reaching the standard target; therefore, in order to obtain more accurate data, a new target sized 3 000×3,000 mm was manufactured. Spray nozzles with different k-factor values were investigated. The experiment made it possible to determine the values of leakage current on a pump unit body and spray nozzle. RESEARCH APPLICATION FIELD. The obtained experimental data indicate the possibility of safe use of water spray and gas automatic fire suppression systems to extinguish live electrical equipment. CONCLUSIONS. The results of the study can provide a substantiation for measures that exclude electric shock to facility personnel in case of using automatic fire suppression systems when extinguishing live electrical equipment.