Introduction. The results of a standard study of the explosibility of aluminum air suspensions (AAS) can contribute to the development of AAS combustion physics. In particular, a complex of information about the polydispersity and of the AAS low explosion limit values in a 1-m³ chamber made it possible to determine the maximum particle size of the explosive fraction of a polydisperse sample d^*_m,t ≈ 40–50 µm (Poletaev, 2014). In the present work, a relationship is established between the AAS combustion dynamics in a 1-m³ chamber and persion. The dispersity of sample particles is described by the mass-average particle size of its explosive fraction (d^*₅₀), in contrast to the works of other researchers who use the mass-average size of all particles (d₅₀).

Initial data. Known information about the dispersity and explosion parameters of 15 aluminum samples studied in a 1-m³ chamber was used. The continuous particle size distribution functions necessary for calculating d^*₅₀ were represented by the Rosin – Rammler distributions filling the gaps between the discrete data of the sieve analysis of the samples.

Combustion dynamics. The dynamics of AAS turbulent combustion in a 1-m³ chamber is represented by the maximum air suspension burn-up rate U_b. U_b was calculated using the formula (Kumar, 1992) intended for gas-air mixtures by substituting the AAS explosion parameters into this formula.

Results and its discussion. A plot of the d^*₅₀ U_b complex versus d^*₅₀  is shown. The average value of the complex (≈ 33 µm·m/s) is constant in the range 10 ≤ d^*₅₀  ≤ 35 µm. The latter is typical for the product of the particle size and the normal velocity of the laminar flame in AAS (Ben Moussa, 2017) and indicates the similarity of the effect of particle dispersion on the dynamics of turbulent and laminar combustion of AAS.

Conclusions. The dispersion of an explosive polydisperse aluminum sample is determined by the average particle size of the explosive fraction of the sample d^*₅₀. The similarity of the combustion patterns indicates a relationship between the mechanisms of laminar and turbulent flame propagation in AAS.

Introduction. The open surface of evaporation of hydrocarbon liquids during their storage in tanks (reservoirs) and in case of emergency spills are the fire hazards characterized by the mass rate of evaporation. The main way to reduce the fire hazard of hydrocarbon liquids is to isolate the evaporation surface of hydrocarbon liquids using various coatings, such as pontoons or floating roofs in tanks (reservoirs), and in case of emergency spills air-filled foam can be used, etc. An effective way to reduce the evaporation of hydrocarbon liquids is to isolate the evaporation surface using light slightly hygroscopic granular materials capable of being retained on the liquid surface by the Archimedean force. The authors address the analytical-experimental evaluation of a decrease in the mass rate of evaporation of hydrocarbon liquids when a layer of granulated foam glass shields the spill surface.

Calculation methodology and results. A mathematical model has been developed to describe a reduction in the evaporation rate of hydrocarbon liquids through a “dry” layer of granulated foam glass, similar to the Bouguer – Lambert – Beer law. A method of experimental evaluation of the mass evaporation rate of hydrocarbon liquids through a shielding layer of granulated foam glass of different height has been developed. Screening coefficients for a number of hydrocarbon liquids and the averaged screening coefficient were identified using the results of an experimental research into parameters of evaporation of flammable liquids (acetone, gasoline AI-92, hexane, ethanol, kerosene, diesel fuel) through a “dry” layer of granulated foam glass of the Termoisol brand (fraction 5–7 mm) obtained using the methodology developed by the authors. Dependences between the rates of liquid evaporation through different thicknesses of a “dry” layer of granulated foam glass on the pressure of saturated vapours have been established. The area height, limited by the bottom concentration limit of the vapour flame, spreading during the evaporation of tested liquids from the free surface that may also have a shielding layer of Termoizol granulated foam glass is estimated analytically and experimentally.

Conclusions. The developed mathematical model and the method of experimental estimation of the mass evaporation rate of hydrocarbon liquids allows to identify the evaporation rate of hydrocarbon liquids of different classes, and it can be used to study the parameters of evaporation shielded by materials having different granulo metric compositions.

Introduction. The purpose of the work is to estimate the temperature of impact on the material under study using the results of synchronous thermal analysis. This task is solved to achieve the pre-set purposes: studying the process of the thermal-oxidative destruction of the material under study, developing thermal impact assessment criteria, and deriving equations to determine the temperature of impact.

Materials and methods. Specimens of ROTBAND gypsum finishing putty, frequently used for the interior decoration of walls of buildings and premises, have been studied. Before testing, putty samples were subjected to the preliminary thermal impact of 200, 300, 400, 500, 600, 700, and 800 °С for 30 min. The tests were carried out using the method of synchronous thermal analysis (Netzsch STА 449 F5 Jupiter) in corundum crucibles at a heating rate of 20 °С/min and with an air flow rate of 75 ml/min.

Research results and discussion. Mass loss at a temperature of 200 °C and ash residue at a temperature of 900 °C can be expediently used as the criteria for assessing the temperature of impact on the gypsum putty using thermal analysis methods. Equations are obtained to calculate the temperature of impact on the gypsum putty composition according to the thermos-analytical characteristics of putty specimens. 

Conclusions. The study demonstrates that synchronous thermal analysis can be applied to determine the temperature of impact on the material under study, which is vital for the analysis of a developing indoor fire.

Introduction. The author analyzes real-life fire resistance limits of metal structures for one building of a thermal power plant. Experimental and computational methods were applied to identify the fire resistance limits of building structures. The temperature setting of the research, conducted to solve the problem, was the same as that of a real fire.

Research goal and objectives. The purpose of the analysis is to identify the fire resistance limits of structures comprising the building of a thermal power plant using the method of heat-mass exchange analysis that takes account of conditions of a real fire. The following objectives are to be attained in compliance with the pre-set goal:

• to analyze the principal provisions of technical norms and regulations in terms of the fire safety of building structures of thermal power plants;
• to justify the principal provisions for the method of heat-mass exchange analysis, taking into account real-life fire conditions;
• to justify the need to improve the real-life fire resistance limits by fire-proofing agents with account taken of the most dangerous scenario of the real fire development.

Methods of research. The heat-transfer equation is analyzed to identify the distribution of temperatures inside a building structure for a one-dimensional case. The field-based method of analysis is applied to solve this problem. This method is generally applied to premises having complex geometric configuration, if one geometric dimension exceeds the others.

Results and their discussion. The authors have analyzed the most dangerous fire scenario characterized by the most dangerous impact on metal structures, such as the furnace oil fire spill in a boiler room.

The authors also address the most dangerous fire propagation scenario in terms of the heating of bearing metal structures: the combustion of furnace oil spills in a boiler room. The computations have proven that in case of the selected fire development scenario maximal temperatures of bearing metal structures are much lower than the critical temperature of 500 °С fifteen minutes after the onset of fire.

Conclusions. Having analyzed the fire resistance computations of thermal power plant structures, including their metal constructions, the have found that in case of emergency, resistance to the most dangerous manifestations of fire exceeds the required R15 value. No fireproofing of bearing metal structures in the boiler room is needed.

Introduction. The authors specify the areas of application of automatic fire-prevention systems and the objects that they protect; they also substantiate the main principles of their design and development. Rational hydraulic sprinkler arrangement patterns are designed for automatic water fire-containment systems to be installed in large and small premises, depending on the thermal loading of structures.

Goal and objectives. Development of recommendations on the use of automatic fire-containment systems and the objects that they protect.

Materials and methods. Fire development patterns were subjected to theoretical and experimental research conducted during variable intensity water supply.

Results and their discussion. As a result of this research, general engineering requirements for automatic water fire-containment systems and their testing methods were first developed.

Conclusions. The first edition of GOST (All-Russian State Standard) “Automatic water fire-containment systems. General engineering requirements. Testing methods” were addressed to the organizations concerned with this area of knowledge; their opinions and suggestions were contributed to another approved edition of this GOST (All-Russian State Standard).

Introduction. Fire suppression systems are stationary technical means designed for fire extinguishing. Their evo- lution relies on the general level of technological development. At present, automatic fire suppression systems (AFSS) are most widely used; they include sprinkler AFSSs, patented in 1864 by Harrison, UK, as well as new robotic fire suppression systems (RFSS). The purpose of the article is to analyze the trends in the development of fire extinguishing systems, and substantiate Russia’s priority in the development of advanced fire extinguishing technologies on the basis of robotic fire suppression systems (RFSS).

Fire suppression systems: from manually operated to robotic ones. Sprinkler fire extinguishing has significant drawbacks; they are low sensitivity and high inertia. Fire monitors are among the main most powerful means of firefighting. Fires are extinguished by firefighters who are in extreme life-threatening environments. The issue of replacing a person during fire extinguishing was studied. Mobile firefighting robots appear in many countries. In practice, stationary firefighting robots are widely used. The first stationary firefighting robot was invented in Russia in 1984 to protect the Kizhi Museum. It was also applied to liquidate the consequences of the accident at the Chernobyl nuclear power plant. The first RFSS was introduced at the Leningrad NPP in 1989. Acting in close cooperation with the VNIIPO EMERCOM of Russia, FR Engineering Centre conducted research to improve the design and control system, establish the regulatory framework for the RFSS. As a result, Russia has become the first country in the world where a new type of automatic fire extinguishing systems, or robotic fire suppression systems, was introduced by the law. RFSS requirements are established by the Federal law No. 123-FZ, GOST R and Codes of Practice. Russia’s priority right for the invention of RFSS is protected by a number of patents.

Conclusions. In our country, long-term research and development have been carried out to design new fire extin- guishing technologies named robotic fire suppression systems. Regulatory and technical frameworks have also been established, and a firefighting robot plant has been built. Now new fire extinguishing technologies, involving firefighting robots, are widely spread; they protect thousands of significant facilities of the country.

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.

The requirements of regulatory documents for the implementation of the safe operation of lithium-ion batteries and storage batteries are presented. A generalization of modern methods for ensuring the protection of lithiu  m-i on batteries has been carried out. External systems for protecting cells and battery packs for the prevention and elimination of emergency and fire hazardous modes of operation are considered. A description of the principles of operation of protective devices and examples of their implementation in practice is given. Examples of the implementation of external electronic protection systems in the form of separate printed circuit boards (BMS) and non-electronic ones — in the form of various cooling systems (BTMS) and fuses are shown.