Introduction. An array of known experimental data, mainly obtained in a standard 1 m³ chamber, is considered in the article. It allowed to identify the nature of three dependences of the turbulent combustion of dust, including the dependences of limited oxygen concentration (LOC) and explosive index Kst on the energy of ignition source E_ig (on a logarithmic scale) and the dependence of K_st on the initial oxygen content in the air C_ox.
Empirical dependencies. The analysis showed that all considered dependences, having a relative accuracy of about 20 % can be represented as linear functions of an argument varying within the following limits: E_ig varies from minimum ignition energy E_min to 10 kJ; C_ox ranges from LOC to 21 % vol. According to the nature of dependence of K_st on E_ig, all dusts are divided into two types. For the first type of dust, K_st does not depend on E_ig. For the dust of the second type, K_st ^∝ (E_ig – E_min).
Relationship of empirical dependencies. It is shown that the considered empirical dependences should be interrelated for the dust of the second kind. Namely, slopes C_n (n = 1, 2 or 3 as the number of the dependence) of linear functions, approximating the empirical dependences for a particular dust sample, satisfy the relationship: С₂(21 vol. %) = –С₁∙С₃(10 kJ). Due to the absence of a dust sample, for which data on all three dependences are available, the obtained relationship was confirmed for the average values of parameters: <С₂(21 vol. %)> = =–<С₁>∙<С₃(10 kJ)>.
Discussion of the result. The satisfactory accuracy of the relationship between C₁, C₂ и C₃ gives rise to the confidence in the objectivity and relationship of the considered empirical dependences of the turbulent combustion of dust.

Conclusions. It is shown that the considered empirical dependences of the turbulent combustion of dust in a 1 m³ chamber are interrelated and the form of this relationship is identified.

Introduction. In theatre and concert halls, acoustic environments are created, among other things, by wall and ceiling panels, that have special sound absorption properties. However, modern materials demonstrating the required acoustic properties do not necessarily comply with effective fire safety regulations.
Aims and purposes. Modern acoustic panels, made of mineral fibers, are among the most effective ones in terms of sound absorption; they also provide wide opportunities for the high-quality design of auditoriums.
Despite the non-combustible basic component, high acoustic performance of such decorative items is attained thanks to a set of supplementary materials that have different chemical compositions, structures, physical and mechanical properties, which, in the aggregate, slightly reduce fire safety.
Due to the lack of fire safety requirements applicable to special materials that perform the function of sound absorption, their usability in auditoriums of buildings and structures is confirmed, as a rule, according to the standards that apply to traditional decorative and finishing materials. At the same time, the use of high-performance acoustic materials is problematic due to rather strict fire safety requirements for decorative and finishing materials designated for walls and ceilings.
The purpose of this work is to conduct analytical studies on the effective regulatory framework of the fire-safe use of acoustic materials, perform comparative experimental studies on the assessment of their fire-technical characteristics to study the feasibility of drafting proposals on their acceptable use on the premises and in the halls of cultural and entertainment facilities.
Results and discussion. Analytical studies were conducted to identify the most effective sound-absorbing finishing materials that feature lower fire hazards. They are mineral wool products made of glass fiber or stone wool. A set of fire hazard indicators, typical for acoustic decorative materials, made of mineral fibers, were subject to comparative experimental studies for the purpose of their legitimate fire-safe use in public auditoriums.
The co-authors found that the requirements, applicable to acoustic materials designated for walls and ceilings, can be issued as amendments to effective regulatory and technical documents on fire safety.
Conclusions. The co-authors proposed amendments to effective fire safety regulations in respect of the requirements applicable to acoustic materials designated for walls and ceilings of auditoriums.

Introduction. Many cultural heritage sites have been converted into multifunctional buildings, which preserve original architectural and structural solutions but fail to comply with effective fire safety standards in many instants. In the event of fire, safe evacuation must be organized from the facilities, that may accommodate a large number of people at a time. Experimental studies are needed to identify the flammability characteristics of materials that can affect safe evacuation from cultural heritage premises.
Goals and objectives. The co-authors suggest a study on the thermal destruction of historical materials, that have been aging in natural operating conditions. The analysis of gaseous products, emitted in the process of thermal destruction, is performed to identify the influence of ancient materials on formation of hazardous fire factors.
Research methods. Experimental studies were carried out to determine the fire hazard indicators for various types of wood, used in the operation of the building, to obtain the reliable initial data, necessary to simulate the dynamics of hazardous fire factors (OFP) when calculating the time to the blocking of escape routes from the Winter Palace.
Flammability properties of wood samples was identified with the support of the testing laboratory of the PB Research Centre at IKBS NRU MGSU. The studies, conducted using thermal analysis methods combined with IR spectroscopy, were carried out with the support from the laboratory of the Federal State Budgetary Institution “SEU FPS IPL” in St. Petersburg.
Results and discussion. The analysis of the results of experiments on materials, has proven that during the thermal destruction of the test samples, regardless of the age and type of wood, acetic acid is released within a certain temperature interval for each sample along with the release of carbon dioxide, and it affects the parameters of fire hazard characteristics of materials.
Conclusions. For the first time in Russia, products of thermal destruction of historical materials have been investigated. The data presented in the article illustrate the need for a further study on gaseous products emitted by historical materials during thermal decomposition. The data obtained by the co-authors can be used to determine the calculated values of the fire risk.

Introduction. The simulation of fire development and suppression processes must take account of a large number of random factors concerning the fire environment and the resources, available for its putting out. An important feature of the fire development is its step-by-step nature, whereby one phase (stage) is naturally replaced by another as a result of physical combustion processes and decisions made amid certain states of fire. In the practice of modeling multiphase (multistage) processes, such models as decision trees, multistep positional games, random processes, including discrete Markov chains, and others are widely used. Each of these models has its own structure and parameters. The choice of the model structure for a particular application represents a heuristic step. In almost every case, parameters of models are set on the basis of logical inferences, physics, ongoing processes and available statistical data about the simulated phenomenon. This approach is usually referred to as normative. Its alternative is an adaptive approach, whereby model parameters are evaluated using historical data. This approach allows to make models that are sufficiently similar to real objects and capable of adapting to the nonstationary features of the environment and the changeability of the decision maker’s preferences.
The relevance of the study lies in the development of a machine learning technology for the Markov models of the fire development process, which allow predicting the completion time of individual phases and the whole fire. The Markov model can also serve as the basis for determining the optimal fire rank.
Goals and objectives. The aim of the work is to create and test the technology for designing models that allow to make projections of the fire completion time. The tasks of the model machine learning and its use as a tool for making projections and determining the rank of fire are set in line with this goal.
Methods. The authors used methods of the theory of random processes, mathematical statistics, simulation modeling, technical and economic evaluations. The research is based on materials extracted from domestic and foreign publications.
Results and discussion. The proposed method, designated for the machine learning of the Markov chains using statistical data on the response time of firefighting and rescue units, coupled with the use of trained models, technical and economic evaluations for assigning optimal fire ranks allow to apply algorithms built on their basis as part of fire safety decision support systems.
Conclusions. The presented solutions to the problem of designing adequate models designated for projecting fire development phases and assigning fire ranks serve as the basis for effective decision support systems in terms of the short-term fire safety management.

Introduction. One of the most important stages in the development of fire and explosion safety requirements applicable to the process of design and operation of oil and petroleum products storage facilities is the correct examination of the facts of fires and explosions. Unfortunately, electronic resources don’t always correctly disclose the causes of fires and don’t allow for the correct assessments of the fire safety level. Goals and objectives. The goal of the study is to improve the quality of evaluation of statistical data on fires arising in reservoirs, based on the use of data from various information sources. The compilation of qualification attributes of causes of fires will simplify the fire examination procedure.
Methods. Research methods include the analysis of statistical data on fires at hydrocarbon storage, transportation and processing facilities. The work encompasses the computational and analytical assessment of the possibility of formation of combustible concentrations in the gas space of tanks and formation of explosive zones outside technological devices.
Results and their discussion. The article addresses features of assessing the fire and explosion safety of tanks by classifying causes of fires at the stage of pre-repair preparation of tanks and hot works. Three principal classification features have been identified: fires that occur during the pre-repair preparation; fires that occur after the fulfillment of regulatory requirements for the pre-repair preparation, and fires caused by major violations of fire safety requirements.
Conclusions. To prevent fires, the issue of tank farm design should be elaborated in detail, fire safety measures should be taken during the operation of hydrocarbon storage facilities, maintenance of equipment should be carried out, preventive maintenance should be executed, as well.

Introduction. The fire resistance limits of load-bearing and enclosing structures can be identified using the method of heat-and-mass transfer calculation in case of fire. The multifactorial nature and nonlinearity of the problem makes the application of this method complicated. If necessary, the temperature regime, demonstrating the conditions of real fire, can be applied. In this work, actual fire resistance limits of metal structures of a thermal power station are calculated.
Goals and objectives. The co-authors attempt to identify the actual fire resistance limits of bearing metal structures in case of the most dangerous fire development scenario.
Methods. Taking into account the complexity of space-planning solutions of a building, the field-focused calculation method was selected. This method is applicable to premises, featuring complex geometric shape, where one geometric dimension is much larger than the others. Non-stationary three-dimensional differential equations of mass, momentum and energy conservation are solved for the gas medium inside a room (the Reynolds type of Navier–Stokes equations), as well as the components of the gas medium and the optical density of smoke. A heat transfer equation is solved to determine the temperature distribution inside the building structure for a one-dimensional case. The fire resistance limit of the building structure is identified as the moment in time following the start of fire, when the temperature in, at least, one point of the structure reaches a critical value.
Results and discussion. Calculation results show that in case of the most dangerous fire development scenario, within 15 minutes as of the start of fire, maximum temperatures of load-bearing metal structures are far below the critical temperature of 500 °C.
Conclusions. Load-bearing metal structures in an engine room, that has steam turbines, don’t need fire protection.

Introduction. An enclosing wall with a wave-resisting visor may be installed to resist the flow of a liquid spill during a tank collapse in accordance with GOST R 53324-2009. This wall should be continuous along the perimeter; it must be made of incombustible materials and have the fire-resistance limit of not less than E 150. As a rule, varieties of heavy concretes are used to construct these walls. However, the actual fire-resistance limit of a structure depends on both its geometric parameters, thermal characteristics and strength properties of concrete used in the case of the long-term exposure to the hydrocarbon fire regime. The work addresses the assessment of the actual fire resistance limit of an enclosing wall with a wave-resisting visor made of heavy concrete designed as the protection for a group of tanks at fuel oil facilities of a thermal power plant.
Calculation methodology and results. The calculation of the actual fire resistance limit of an enclosing wall with a wave-resisting visor, designated for a group of fuel oil tanks was performed. The co-authors used the results of studies on the substantiation of a hydrocarbon fire resulting from a flammable liquid spill and a tank failure, empirical dependences for determining the thermal engineering parameters of heavy concrete, as well as experimental data on a change in the compressive strength of concrete at temperatures up to 1,200 °C. The calculation results show that this wall structure can maintain stability for more than 10 hours. Note that the load-bearing capacity of the wall is more than 11 times greater than the bending moment triggered by the standard load. Indeed, the fire resistance of the wall is not less than RE 600. It exceeds the normative values for these types of walls by a factor of four.
Conclusions. A common algorithm can be used to calculate the actual fire-resistance limit of enclosing walls of oil and petroleum product tank storage facilities, set by Construction Regulations 468.1325800.2019. At the same time, the results of the above theoretical and experimental studies are recommended for use as the initial data.

Introduction. The article addresses the fire situation in rural areas of the Russian Federation and estimate the number of fire brigades that assure fire safety there. The purpose of the study is to analyze integral fire risks and a composite indicator of the fire hazard in Russia’s rural areas and federal districts. The scope of research is the probability of fire occurrence in the territory of the Russian Federation. The focus of research encompasses values of integral fire risks in rural settlements and a composite rural fire hazard indicator, calculated using these values.
Methodology. The theory of integral fire risks serves as the methodological framework for the study.
Results and discussion. As a result of the study, it was found that the values of principal integral fire risks in rural areas of Russia are 2–3 times higher than those in urban areas. Similar results are obtained in other countries, in particular, in the United States. Values of the same fire risk are provided for urban and rural areas of the United States.
Conclusions. The results obtained in the study can be used to solve problems of fire safety management in rural areas. The objective level of the fire hazard in rural areas of Russian federal districts was identified. It is advisable to conduct a similar study of the fire situation in rural areas of subjects of the Russian Federation.

Introduction. The relevance of the study is substantiated by the need for a safe and timely arrival of an emergency service vehicle (firefighters, police, paramedics, gas service teams) to the place of call under the conditions of poor road visibility due to smoke, fog, snowfalls, the night time in the absence of illumination.
Ensuring safe movement under the conditions of poor visibility. In case of smoke and insufficient visibility due to wildfires, safe movement is possible, if the air pressure in the cabin is excessive and the driver uses a thermal imager by. When a car is driven under the conditions of fog, a snowfall or the lack of illumination, a thermal imager can also be used. The gas-dynamic analysis of air supply to the cabin and its schemes are provided. The co-authors made a gas-dynamic assessment of the air flow rate if the cabin is not hermetically sealed and the crew stay inside.
The car movement in case of floods and damaged roads. The structural layout diagram of an emergency service vehicle designed to move through flooded areas and along damaged roadbeds is provided.
Conclusions. The novelty and expediency of the above technical solutions are confirmed by the RF patents. Their implementation will allow emergency services to arrive safely to the place of call, regardless of the road conditions.

The statistics of fires at electric plants, broken down by the types of electric products, are considered. The need for a further search for technical solutions towards the protection of electric networks from large transient resistances is substantiated. Basic provisions of the contact theory are presented. The influence of various factors on the value of the transient resistance is shown. The generalization of theoretical data has been carried out, allowing to determine the ways of solving the problem under consideration.