One of the main directions assisting in solving the tasks setting in front of the Fire and Rescue Division of Federal Fire Service of Emercom of Russia is the development of new tactical procedures (TP) of conducting operational activities during the fires and emergencies. Herewith the fire-rescue forces new TP adopting must be preceded by a number of trainings (experiments) proving its higher efficiency (based on specified criteria) compared to the existing ones. However, experiments for testing new TP requires large expenditure of forces, time and money. Moreover, the experiment is not possible in cases of its connection with life or health risks. Under these conditions and restrictions it is necessary to adopt or reject the new developed TP of forces action in a limited number of exercises. The math statistics method, called the sequential analysis method (SAM), allows not pre-determine the number of required observations. The solution at the end of checking developed TP experiment is taken at each experiment (exercise) stage. It depends on previous tests results. The main advantage of the SAM in comparison with the classical math statistics methods (author - A. Wald) is the much smaller number of observations. The possibility of decision making process math modeling of adopting the Fire and Rescue Division of the Federal Fire Service of Emercom of Russia new tactic action by means of SAM is considered in the article. The underlying method formula conclusion is justified. The both interpretations - graphical and tabular are presented. The examples of SAM practical realization in cases no reason to give preference to either of two action modes before the experiment are presented. Obviously, the SAM math modeling is practically useful and allows to take the guaranteed and science-based decision on the new developed forces action TP with high reliability and precision for a relatively small number.

Vibration combustion is wave process. It is excited in result of interaction of the flame front with a depression wave which is formed as a result of sharp decrease of speed of a thermal emission, because of decrease of burning area at contact of a flame with the walls limiting volume. The flame under the influence of a wave of expansion tries to return to former situation and again to increase burning area. Fluctuations of gas and fluctuation of the combustion zone are as a result generated. Fluctuations amplify - the flame loses stability, combustion accelerates. The more the camera volume, the easier a flame loses stability. There are especially inclined to vibration combustion of mix, showing diffusion and thermal instability. Mixes with a lack of a mild component belong to such mixes. Speed of heat release and pressure in volume change with oscillation frequency of gas that complicates the expirations from volume. The combustion mode at the strong fluctuations passes from the surface in volume that is followed by change of character of a luminescence of the combustion zone. Amplitude value of pressure in waves can exceed several times pressure against the background of which vibration combustion develops. In squared volumes in the mode of vibration combustion the mix which remained in corners as combustion in this case is stabilized in corners burns down. Experiences in which fluctuation of gas was suppressed with a covering of walls with a felt took place without vibration combustion. In self-contained volumes vibration combustion is also excited in result of interaction of the combustion zone with volume walls in this case stabilization it is not required as the expiration of gases does not happen. When smoothing corners of volume vibration combustion quickly stops. Otherwise combustion in corners does not reach as the flame is extended with the expiring gases. It is apparent that the processes happening at vibration combustion cannot be described by means of quasi-stationary representations. Building constructions of buildings of explosive productions need to be counted taking into account possible pressure roughness if there is a threat of emergence of vibration combustion.

The aim of this study was to determine the relationship between flash point, spontaneous ignition temperature and vaporation enthalpy of saturated hydrocarbons with the composition and structure of their molecules in the framework of additivity of chemical bonds. Analysis of data on flash point has shown that for saturated hydrocarbons the contribution of a methylene group CH-bond is observed as a constant for compounds, starting from dodecane. The spontaneous ignition temperature of paraffin hydrocarbons of normal structure, starting from n-nonane does not change and equal to (204±2) °C. In this case the contribution of the methylene group CH-bond is formally equal to zero. Generally for normal paraffins asymptotic dependence of the contribution of the methylene group CH-bond in the flash point and spontaneous ignition temperature from the size of the molecules has been observed. It is found that some other properties of liquids (density, thermal coefficient of volume expansion) also reveal the asymptotic dependence from the molecular size. In the present study, we exploit the exponential model with three fitting coefficients to describe the asymptotic dependence of the flash point and spontaneous ignition temperature of saturated hydrocarbons. The corresponding correlation equations have been obtained. It has been suggested that the same type of dependencies caused by various reasons. The asymptotic dependence of the flash point temperature, associated mainly with the process of partial evaporation of the liquid, due to competition of intermolecular and intramolecular interactions in the liquid phase. The asymptotic dependence of the spontaneous ignition temperature of hydrocarbons related to the substance oxidation process, caused by the change of the mechanism of chemical interaction. The analysis of literature data has shown that there is a good linear dependence of the vaporization enthalpies of n-alkanes at 25 °C from the size of their molecules. Therefore, the contribution of methylene groups and the structural fragment CH_s in the vaporization enthalpy is constant, regardless of the size of the molecule of the n-alkanes. The regression equation for describing and predicting the flash point of paraffin hydrocarbons and their isomers has been obtained. For the spontaneous ignition temperature in the framework of the used approach it has not been made.

A study is a modification of wood with phosphorous acid esters in order to reduce fire properties. It is known that phosphorus-containing modifiers are effective flame retardants for wood. Finding the best characteristics to evaluate effectiveness of modifiers is the most rational way to select modifiers, which reduce the fire properties of materials. A significant characteristic for evaluation of effectiveness of surface layer modifiers is a surface energy. To achieve the goal, the task was to study the change of energy characteristics of the modified wood surface and study of thermodynamic optimization of modifiers, which reduce the fire properties of materials. The thermodynamic parameters of the modified wood surface were determined on the basis of which it is possible to select the modifiers of the surface layer for wood. The change of the isothermal-isobaric ensemble of the modified surface was calculated on the basis of the combined equations I and II of the laws of thermodynamics using the “neutral drop” method. The largest values of surface energy are characteristic for wood, which modified by compounds entering into effective chemical interaction with wood. The degree of chemical interaction of the modifiers with wood was studied by the elemental analysis. High values of surface energy are substantiated when studying the structure of the surface and the surface layer of modified wood. The structure of the surface of the wood was studied by electron microscopy. The capillary structure of wood was studied by the method of sorption of water vapor. It is shown that with a high degree of interaction of the modifier with wood, the surface porous layer of wood is strengthened and structured and the pore size is reduced. As a result, there is a reduction in fire hazard and smoke generation ability. The most effective modifier is DEF, which provides the I group of flame retardant efficiency and reduces the smoke generation ability by 6 times. The possibility of the thermodynamic optimization of modifiers to create flame retardants was shown. The most effective modifiers providing high fire resistance of wood are characterized by the most negative values of the isothermal-isobaric ensemble change.

The paper discusses the problems of protection of reinforced concrete tunnel structures from brittle (explosive) destruction of concrete tubbing lining of the tunnel. The relevance of the research is attributed to increasing pace of construction of deep-level tunnels. Fires in such facilities could be catastrophic, often resulting in massive loss of life and great material losses, and their suppression requires involvement of considerable forces and assets. During the construction and operation of road and subway tunnels, the protecting structures - reinforced concrete lining blocks have a higher moisture content, which in the event of fire in the early stages can lead to brittle failure of concrete tubing and the premature loss of their load-bearing capacity. To reduce the effects of brittle fracture of concrete in the protective layer of concrete structures anti-spall mesh is installed, or fire retardant coating is used which reduces the intensity of heating of concrete during fire. However, recent studies have shown that the most effective way of protecting against brittle fracture of concrete from the point of view of labor and material cost is the use of additives in the concrete mixture in the form of polypropylene fibers. Earlier, experiments were carried out in VNIIPO to determine the actual limits of fire resistance of tunnel tubing and the influence of polypropylene fibers additives in concrete mix on the likelihood of brittle fracture of concrete. However it seems impossible to assess the fire resistance of similar structures using numerical methods due to the lack of baseline data on the strength and thermo-physical properties of concrete with polypropylene fibers. To achieve this goal, studies were conducted of concrete strength under axial compression with the addition of polypropylene fibers in the amount of 1 kg/m³ and experimental data of thermal characteristics of fiber-reinforced concrete at high temperatures were obtained. The paper presents the results of experiments on the samples of fiber concrete under axial compression when exposed to temperature in the range 20-800 °C. Graphics show the process of the strength change of concrete with and without additives during heating. Analytical dependencies for determination of strength of concrete under compression were obtained with two types of polypropylene fibers at high temperatures.A comparison of the strength properties of the investigated concrete mixtures was carried out. It was established experimentally that when using the polypropylene fibers, the strength characteristics of fiber-concrete are reduced on average by 16 %, compared to the concrete without fiber additives, both at normal and high temperatures. As a result of processing of the experimental data by regression analysis the analytical dependencies were obtained for determination of strength characteristics of concrete under axial compression with the addition of domestic and imported fibers when exposed to high temperatures. Experiments to determine the thermal properties of concrete with the addition of polypropylene fibers, were conducted during one-sided heating of board samples on the temperature regime of “standard fire”. In the presence of experimental data, by solving the inverse heat conduction problem using the previously developed computer program, the thermophysical characteristics (thermal conductivity and heat capacity) of fiber-reinforced concrete at elevated temperatures were defined. With increasing temperature, the thermal conductivity decrease is more intensive in concrete with added polypropylene fibers than that of concrete without additives. At the same time, the addition of fiber does not affect the intensity of increase of the heat capacity of concrete. The obtained dependences of thermophysical properties of concrete with domestic and imported polypropylene fibers on temperature increase make it possible to carry out calculations of heating of concrete structures with selected additives on a temperature regime of “standard fire”. The conducted studies on the effect of temperature on the strength and thermal properties of concrete with addition of polypropylene fiber reinforcement can be used in calculation of the fire resistance of load-bearing and enclosing structures made of this type of fiber-reinforced concrete.

Effective use of cultural heritage objects is nowadays a very actual problem. Main trends of cultural heritage object modification for modern use are multifunctional complexes, business centers, hotels, educational institutions. Also there is successful experience of modification of industrial architecture into exhibition areas, concert venues, art-venues, modification of historic building complexes. Russian and international normative documents with fire safety requirements for cultural heritage objects are analyzed in this work with respect to design experience, and improvement proposals are developed. Reconstruction, major repair, modification for modern use for cultural heritage objects can result in contradictions between requirements of Federal Law No. 123 “Fire Safety Regulation” and space-planning and construction solutions which are protected as cultural heritage elements. At the same time, some space-planning solutions at the objects can’t be taken into account in fire risk assessment according to approved technique (RF Emercom Order on 30.06.2009 No. 382). As a result it’s difficult to accept appropriate use of this technique in such cases. It’s suggested to develop Code of Practice which could explain and validate design solutions in such cases. Before technique actualization it’s suggested to develop Special Technical Regulations for fire protection of these objects. Building elements, which are not taken into account in the technique, can be included in fire assessment by expert coefficients to use upper limits of evacuation time in the assessment. Actual for practice specialists, typical for cultural heritage object problems are considered in this work: protection of multi-storied spaces with open stairways; automatic fire-suppression installations; historic doors in fire partitions; smoke control systems. Suggestions for application of such fire protection facilities at cultural heritage objects are formulated.

A large number of parishioners in the mosque determines the need to secure their safety in case of fire. For this purpose, there are defined the demographic of people in the mosque (over 95 per cent of working age) and the rate (0.6 m² of area per one praying person of the total area of the mosque that is vacant from equipment and the elements of the decoration of the hall). The peculiarity of the evacuation process from mosques is the high number of people, the low time of the beginning of evacuation (4-5 sec) and, as a consequence, momentary formation of streams with high density. Based on the established in the theory of human flows of methods conducting observations on location mosques of Moscow, a series of observations on location had been conducted in the days of their highest point of parishioners. As a result of the research, based on more than 1500 measurements, the dependences between the parameters of the human flow V_D = φ( D ) for the first time had been established during its movement along the observed way during the evacuation from the mosques. The high theoretical correlation ratios obtained in all the presented dependences (η_t = 0.999) determine the established ties practically as functional (η_t = 1.0), which indicates on the presence of the strong correlational tie between the speed of parishioners movement and the density of the flow. It is established that in order to provide free evacuation, the width of the exits should be set in proportion to the width in the shoulders of the people that make it up (b = 0.9 m), but not less than the width of the wheelchair (b = 0.9 m). In such a way the width of the doorway must be at least 0.9, 1.2, 1.8, 2.4 m etc. In mosques, as a rule, the evacuation time is determined by the time of movement through the door openings. The maximum intensity of movement through the doorway is determined as a result of the experiments lower by 14.5 per cent than the data existing today in the standards. This is due to the physiological and demographic changes observed in last decades in the structure of the population.

A brief analysis of the article “Probabilistic approach to the modeling of fire development on open land by the use percolation process and function of the neural network”, published in the journal Pozharovzryvobezopasnost / Fire and Explosion Safety, 2017, No. 2. Shown that the application of percolation methods to the development of fires in rural areas is incorrect. Encouraged to consider the descriptions of management of the suppression of such fires based on neural network technology.

ВОПРОС: Согласно статистике в нашей стране большое число пожаров происходит из-за некачественного монтажа электроустановок. Под некачественным монтажом подразумевают ненадежное или непрофессиональное соединение проводов и кабелей, которое приводит к возникновению переходных сопротивлений. По этой причине в местах контакта происходит локальный нагрев проводников, что зачастую становится причиной пожаров. Самым распространенным и быстрым способом соединения проводников является скрутка. Какие требования предъявляются к порядку выполнения и применения скрутки проводников при монтаже электроустановок?