Introduction. New provisions, introduced into building regulation codes, necessitate a revision of the set of rules titled “Fire protection systems. Fire resistance of protected items” in respect of fire resistance limits and fire hazard classes of building structures, dimensions of fire compartments, as well as their detailed elaboration with account taken of the characteristics of buildings that perform different functions.

Goals and objectives. The purpose of the article is to substantiate the revised provisions of the set of rules “Fire protection systems. Fire resistance of protected items” with account taken of the new provisions of building regulation codes.

Methods. An analytical method is used to formulate and substantiate the requirements for a fire protection system based on the comprehensive evaluation of provisions of the Federal Law of the Russian Federation dated July 22, 2008 No. 123-FZ “Technical Regulations of Fire Safety Requirements” (hereinafter — No. 123-FZ) and provisions of building regulation codes.

Results. The contribution of the work results to the new edition of the set of rules JV 2.13130.2020 “Fire protection systems. Fire resistance of protected items” ensures the harmonization of this document with the requirements of building regulation codes.

Conclusion. The research findings allow to optimize the requirements for fire resistance limits, fire hazard classes of building structures, and the size of fire compartments. The research results also help to clarify these requirements with regard for the characteristics of buildings that perform different functions.

Introduction. High-temperature gas flows often occur in case of a fire at oil and gas facilities; gas flows out of holes, cracks, ruptures in depressurized items of equipment and pipelines. The fire-retardant efficiency of intumescent coatings of steel structures, exposed to high-temperature gas flows, plummets. Hence, the task of developing a methodology for the adequate assessment of their fire-retardant efficiency is relevant.
Goals and objectives. The purpose of the study was to develop a methodology for evaluating the fire-retardant efficiency of intumescent coatings for steel structures exposed to high-temperature gas flows and experimentally evaluate the fire-retardant efficiency of various intumescent coatings. The following research-focused tasks were solved: the evaluation of the velocity of high-temperature gas flows leaving depressurized items that normally operate under pressure; the analysis of the methodology designated for identifying the fire-retardant efficiency of intumescent coatings of steel structures in a calm (sedentary) gaseous medium; the development of a method for evaluating the fire-retardant efficiency of intumescent coatings of steel structures exposed to high-temperature gas flows; the experimental evaluation of the fire-retardant efficiency of various intumescent coatings in a high-temperature gas flow.
Methods. The velocity of high-temperature gas flows, leaving depressurized items that normally operate under pressure, has been calculated. The co-authors have analyzed the established methodology used to identify the fire-retardant efficiency of intumescent coatings of steel structures in a steady (sedentary) environment, where gas temperature in a furnace is the only factor taken into account. The co-authors propose a method for evaluating the fire-retardant efficiency of intumescent coatings of steel structures exposed to high-temperature gas flows, which takes into account gas flow temperature and velocity. To evaluate the fire-retardant efficiency of an intumescent coating exposed to a high-temperature gas flow, a coefficient of relative fire resistance is introduced. An experimental evaluation of various intumescent coatings is carried out. It shows a substantial fire- retardant efficiency decrease in a high-temperature gas flow that fosters the hydrocarbon temperature regime.

Results and discussion. Mutual aerodynamic and thermal effects of a gas flow substantially reduce the fire- retardant efficiency of intumescent coatings of steel structures, and this is proven by the results of experiments conducted according to the proposed method. The method for evaluating the fire-retardant effectiveness of intumescent coatings of steel structures takes into account the temperature and velocity of a gas flow that affects the sample.
Conclusions. It is relevant and necessary to evaluate the fire-retardant efficiency of intumescent coatings of steel structures at oil and gas facilities, operating under pressure, since a substantial decrease in their fire-retardant efficiency is observed in high-temperature gas flows.

Introduction. To enhance combustion in arson attacks, arsonists often use accelerants, or easily accessible petrochemicals, such as gasoline, diesel fuel, as well as their mixtures. As a rule, accelerants are submitted for investigation as traces left on the surface or inside objects of evidence. If objects of evidence are damaged by the fire heat, thermal decomposition products may be formed, and their composition is similar to the one of petrochemicals.

Goals and objectives. The goal of the study is to use fluorescence spectroscopy to study extractive components of the burnt laminate, as one of the most common types of floor coverings, and identify their influence on detec- tion of accelerants.

Methods. The study is focused on extracted samples of the Tarkett laminate, having physical dimensions of 50 × 50 mm2, exposed to the thermal impact in a muffle furnace at the temperatures of 300, 400 and 500°C for 2–10 minutes. The samples were studied using fluorescence spectroscopy at the fluorescence excitation wavelength of 255 nm.

Discussion. The fluorescence spectra of the laminate samples, showing signs of minor thermal damage (color change), include a single wide peak of 300–410 nm with a maximum in the area of 340 – 370 nm. The shift of the fluorescence maximum and the emergence of peaks in other areas of the spectrum are typical for laminate samples, on the surface of which a carbonized layer is formed at the temperature of 300°C (600 s) and 400°C (240, 360 s). An increase in the thermal damage of samples, accompanied by the destruction of the carbonized residue, leads to the decrease in the fluorescence intensity of their extractive components to background values. 

Conclusion. The fluorescence spectra of the laminate samples, obtained by means of burning at 400°C for 240–360 s, have peaks in the area of bicyclic and tricyclic aromatic hydrocarbons, which impede the identifiability of accelerant traces that may be present as heavy oil fractions (oils, lubricants, fuel oil), highly burnt diesel fuels.

Introduction. The reliable operation of safety systems, that allows for the failure of no more than one safety system component, entails the safe shutdown and cool-down of an NPP reactor in the event of fire. However, the co-authors have not assessed the loss of performance by an insulating material, treated by intumescent compositions and used in the power cables of the above safety systems exposed to the simultaneous effect of various modes of fire and current loads.
Goals and objectives. The purpose of the article is the theoretical assessment of the application efficiency of intumescent fire-retardant coatings in power cables used in the safety systems of nuclear power plants having water-cooled and water-moderated reactors under fire conditions. To achieve this goal, the temperature of the outer surface of the insulation and the intumescent fire-retardant coating was analyzed depending on the mode of fire. Theoretical foundations. A non-stationary one-dimensional heat transfer equation is solved to identify the temperature distribution inside the multilayered insulation and the fire-protection layer of a conductive core.
Results and their discussion. The co-authors have identified dependences between the temperature of the outer surface of the insulation and the fire retarding composition of the three-core cable VVGng (A)-LS 3x2.5-0.66, on the one hand, and the temperature of the indoor gas environment for three standard modes of fire and one real fire mode. It is found that before the initiation of the process of destruction of the insulation material, the intumescence of the fire-retardant coating occurs only in case of a hydrocarbon fire. Under real fire conditions, the maximal insulation melting time before the initiation of intumescence of the fire-retardant coating at the minimal temperature of intumescence is 4.75 minutes, while the maximal time period from the initiation of destruction of the insulation material to the moment of the insulation melting is 6.0 minutes.
Conclusions. An experimental or theoretical substantiation of parameters of intumescent fire retardants, performed using standard modes of fire, has proven the potential loss of operational properties by insulating materials of power cables, used in the safety systems of nuclear power plants, in case of a real fire. Therefore, it is necessary to establish a scientific rationale for the efficient use of fire retardants in the above cables with regard for the conditions of a real fire.

Introduction. The article offers a detailed description of the notions of intensity of human flows and traffic streams. The values of their intensity are determined by the capacity of a road that is one meter wide. The article also offers a description of the flow/stream density and speed that determine their intensity. The co-authors have demonstrated that the flow/stream density is a technical parameter that characterizes the mobility of humans in a flow. The influence of people on the human flow speed is identified with the help of coefficients of motion conditions. To distinguish between the areas of application of these two notions in the process of developing a route optimization methodology, the co-authors addressed the properties of human flows and the road section capacity that depend on the flow width and the road section width. The theory of human flows employs the statistical analysis of human flows to identify the relationship between the parameters of a human flow, based on regularities of psychophysics, and its mathematical anticipations are described by an elementary stochastic function, which means that a human flow is a stochastic process.

Subject of research. The intensity of interdependent human flows and traffic streams.

Goals. The purpose of the article is to identify and demonstrate explanations of differences between the intensity of human flows and traffic streams.

Materials and methods. Collecting and analyzing the research literature focused on human flows and traffic streams.

Results. The co-authors have shown that a traffic stream is an independent system that is determined by uncer- tainty, finitude, and dependence of distance on time. The value, that ties all the parameters, that characterize the process of human motion, is the road capacity, while the motion intensity is defined as the product of density times speed.

Conclusions. The identified dependence between the human flow parameters serves as the basis for stan- dardizing different escape routes and exists from buildings performing different functions. The currently used methodology applies the regularities thus identified to simulate human evacuation processes in the course of design and operation of buildings and structures in order to assess the value of the fire risk, while the results of multiannual research projects are contributed to statistical databases used to develop construction rules and regulations.

Introduction. The destruction of foam films occurs when they reach critical thickness and lose the liquid phase as a result of syneresis and evaporation, which are rather difficult to slow down. We have proposed a method for increasing the stability of the fire extinguishing foam by means of replenishing the liquid phase through sprinkling.
Methods. Foam stability was measured by the time of destruction of 25 % of the initial foam volume. The concentration of the foaming agent in the sprinkled solution varied from 0.5 to 6 %. Carboxymethylcellulose sodium salt (Na CMC) was used as a stabilizing additive. Field studies were carried out by feeding foam and solution from two AT-3,2-40 (43253)001-MS tank cars.
Results and discussion. It has been established that the foam stability is influenced by the sprinkling intensity and the foaming agent concentration. Foam sprinkling with the solutions having low concentration of thefoaming agent leads to the washout of surfactants from the films that reduces the foam stability. The sprinkling intensity reduction boosts the foam stability due to the replenishment of the moisture lost through evaporation. The foam stability was maximal in case of sprinkling with a 2 % solution of the foaming agent, while the sprinkling intensity had no influence. An increase in the concentration of the foaming agent in the sprinkled solution led to a decrease in the foam stability. It is found that a smaller amount of the foaming agent is consumed to maintain the amount of foam through sprinkling than to replenish the destroyed amount through additional foam generation. It is shown that various stabilizing additives can be added to the foam in the process of sprinkling. If Na CMC is added to the solution exposed to sprinkling, the time of foam destruction goes up 3–5 times even in case of a non-recurrent sprinkling session. Field tests have confirmed the feasibility of adding stabilizing additives to the foam by means of sprinkling.
Conclusions. The results of the research have shown the feasibility of co-feeding the foam and surfactant solutions, containing various stabilizing additives, in order to extinguish fires and generate stable foams.

The article addresses the problem of bridging the divide between the present-day technological advancement, primarily in the field of normative legal and technical regulation of fire safety, and the qualification of persons, authorized to regulate relations in fire safety assurance (hereinafter — “Authorized persons”) in the context of transition of the state regulation of fire safety relations from an obsolete standard target model to a new analytical and scenario-based (risk-oriented) target model used to make decisions in the area of control over the safe condition of the technosphere in view of a sudden increase in the dynamics of sociocultural processes.
The Education and Research Supervision Unit of the State Fire Academy of the EMERCOM of Russia (the Ministry for Civil Defense, Emergencies, and Elimination of Consequences of Natural Disasters), responsible for the drafting of suggestions concerning the implementation of point 10, Minutes № 1 of the meeting of the workgroup of EMERCOM of Russia on May 20, 2019 “Regarding the arrangement of interaction with the management authorities of the institutional firefighting service of executive federal authorities and organizations”, has developed “The list of milestones of professional culture for the persons responsible for regulating relations in the field of fire safety for the period of transition from a standard target model to the risk model of controlling, supervisory, and authorization-related activities” (hereinafter — “the List”).
This List represents a basic set of conceptual professional milestones, whose attainment enables authorized persons to re-focus their conscience from an obsolete standard paradigm, used to make decisions in the area of fire safety, to a new risk-oriented one.
Given the focus of this article, it defines some, or the most significant, milestones of professional risk-oriented culture of authorized persons.

The article addresses the requirements of regulatory and technical documents on the flame retardant treatment of cable products. It also presents methods for evaluating the fire-proof efficiency of various compositions. The cases, described by the co-authors, have overviews of the fireproofing sequence and acceptance procedures. The co-authors demonstrate approaches to determining the service life (the lifespan) of protective coatings. Information on various methods, used to check the condition of previously applied fireproofing, is summarized. Relevant conclusions are drawn about the options of the fireproofing application to ensure the fire safety of buildings and structures.