68 the fire, but there was a danger to the health of Lviv citizens since the container was placed near a trolleybus stop. Extinguishing the fire lasted for several hours because magnesium cannot be extinguished with water, and the means that were available did not make it possible to do it quickly. In Crimea, on October, 17, 2009, a fire started at a depo that stored poisonous chemicals ("Otradnoye", Dzhankoy region). The resulting fire burned about 160 tons of poisonous chemicals. The area of the fire was about 600 square meters. The depo had stored magnesium-containing pesticides since 1960s-1970s. According to one explanation, it is the magnesium that caused a spontaneous combustion of pesticides.

The analysis of the problem of extinguishing fires of magnesium and its alloys is carried out. The urgency of studying the problem is confirmed by the fact that during the extinguishing of class D fires there are factors that can complicate the quenching process. Often, these metals actively react with water, which leads to an even greater spread of the fire and even an explosion. Therefore, special fire extinguishers, which have passed the proper test, are more effective in locating the fire and prevent the burning of the powder to form the "tongues" of the flame. In Ukraine, there is no method for testing the effectiveness of fire extinguishants of special purpose for the extinguishing of class D fires. The normative documents have been analyzed, which specify the procedures for testing extinguishing fire-extinguishing special-purpose fire extinguishing class D. Specifically: the methods are described in the international standard ISO 7165: 2017 «Fire fighting – Portable fire extinguishers – Performance and construction» and GOST 53280.5-2009 Fire fighting systems automatic. Extinguishing agents. Both methods have a number of shortcomings that need to be addressed when creating a Ukrainian fire test method for extinguishing fire extinguishing class D, namely: the dimensions of the metal frame made of sheet steel with a side (500 ± 10) mm, height (150 ± 5) mm for testing with magnesium chips are small; Not specified quantity of gasoline necessary for the rise of magnesium; The gas or oxygen torch used to dissolve magnesium does not provide full-value combustion throughout the area, but only creates separate cells of ignition. A draft methodology has been developed that determines the fire-extinguishing efficiency of powdered powders used in Ukraine. The required amount of fuel for burning magnesium and its alloys is determined. It was ascertained that for the firing of magnesium chips it is necessary to use at least 127 grams of gasoline of the mark A 92. Key words: test method, fire extinguishers of special purpose, extinguishing of fires of magnesium alloys

The scope of magnesium and aluminium and their alloys in industry, construction and life are expanding over time. As a rule, there are no clean fires of class D, which include combustion of magnesium, aluminium and their alloys. The problem is that the temperature of combustion of magnesium and its alloys can rise above 2800 Celsius degree. Magnesium burns even in the atmosphere of nitrogen and carbon dioxide and such fire is very difficult to extinguish. When water contacts the magnesium or other light metals, the area of fire expands. The main purpose of this work is to study the combined extinguishing of light metals fires, Class A fires and class B fires with a special dry chemical powder and high resistance foaming agent. The problem of extinguishing fires at objects with the using of light metals (magnesium, aluminium) and their alloys has been explored. Class D fires usually lead to class A and class B fires. They occur at high temperatures, and may cause explosions. Scenarios for the development of fires can be as follows: burning of light metals or solid combustible materials ad initium and light metal fire that requires combined extinguishing methods afterwards. Dry chemical powder formulation for extinguishing class A, B, D and and electrical installations under voltage, which includes: sodium chloride, blast furnace slag, ammophos, aerosol has been developed. Testing of this powder has been carried out in the laboratory using chips of magnesium and aluminium alloys. The combustion area in all experiments has been equal to 2.85 × 10-2 sq. m. The quality of the powder has been evaluated by the intensity of the D class fire and the extinguishing time of the B class fier. Dry chemical powder KM-2 has been tested for extinguishing fires 21B, 1A. and for magnesium alloy chips fires. Combined extinguishing tests were conducted on class D, class A and class B fires in field conditions. Method of combined extinguishing with the dry chemical powder followed by covering the entire burning area with high-expansion foam has been proposed (the fire with total area of 2.5 square meters has been extinguished for 45 s). Extinguishing methods have been tested on model fires. Safety measures for light metal extinguishing have been developed. Conclusions: formulation for universal KM 2 dry chemical powder for extinguishing class D, A, B fires, which consists of sodium chloride, ammophos, slag, aerosil, has been developed. Successful extinguishing of class D and B fires has been carried out succesfully; technology of combined fire fighting D and A has been substantiated.

This research outlines the problems of fire extinguishing in tanks, and describes a projected model of an experimental installation for the vertical tank fire simulation. The research also describes a method of extinguishing fires of oil and petroleum products in vertical steel tanks by supplying low expansion foam to the tank base directly into the fuel layer. The time of diesel fuel and gasoline fires extinguishing with the help of general and special purpose fire-fighting foam agents was calculated. Experimental investigations on definition of the fire-extinguishing efficiency of domestically producted fire-fighting foam agents by subsurface fire extinguishing of tanks were carried out.

Introduction Despite the significant progress in technology, including the field of fire safety, fires of oil and petroleum products tanks remains one of the most difficult ones to extinguish. This type of deflagration develops rapidly, has protracted nature and requires the involvement of a large number of means and forces. Also, such fires cause enormous material and environmental damage and pose a significant danger to people's life and health. One of the safest ways to extinguish fires in oil and petroleum products tanks is a subsurface fire extinguishing method. This method uses foam concentrate with fluorinated stabilizers, an aqueous solution of which can cover the surface of petroleum products with a thin film. At the moment, this issue is not researched well enough in our country. The official Ukrainian regulation documents describe technical parameters of oil tanks extinguishing system, but the method described in these documents is the same for both subsurface fire extinguishing and surface foam supply. Therefore, a specific methodology for calculating the main parameters of the subsurface tank extinguishing system is necessary. Purpose The purpose of this study is to describe the methodology for calculating the main parameters of the subsurface tank extinguishing system. Calculation of the different technical parameters of the subsurface method-based extinguishing system depending on the tanks type, fuel types, concentrations of foaming agent, etc. is provided. Results This research outlines the main problems of fire extinguishing in tanks with oil and petroleum products, and specifics of their elimination by supplying fluorosynthetic foaming agents into the layer of combustible material. The research also describes calculation methods of the main parameters of the subsurface fire extinguishing method for extinguishing fires in oil and petroleum tanks using low expansion foam. Examples of calculation using tank RVS-10000 for both proposed methodology and methodology described in the official Ukrainian regulation documents are provided. Various technical parameters of the subsurface method-based extinguishing system were calculated depending on the tanks type, fuel types, concentrations of foaming agent, etc. Conclusion The results of this research prove that spendings on foam agents and damages from the oil fire can be reduced when using subsurface fire extinguishing method.