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Vol 118, No 1 (2025)
- Year: 2025
- Articles: 10
- URL: https://journal-vniispk.ru/2411-3778/issue/view/21294
Scientific and Technical Developments
Simplified calculation of the actual fire resistance of steel structures with an epoxy thermally expanding flame retardant coating under the influence of a hydrocarbon temperature regime
Abstract
A series of experimental studies to determine the fire protection efficiency of two-component epoxy thermally expanding coating for steel structures when exposed to hydrocarbon temperature regime has been carried out. The calculated thermo-physical characteristics of the flame retardant coating have been obtained. Based on calculation results there are constructed nomograms of heating of steel structures with the reduced thickness of metal from 2 to 20 mm and the thickness of epoxy coating from 1 to 9 mm. The obtained nomograms combined with the calculated value of the critical temperature allow to assess the fire resistance of steel structures of any configuration with different thicknesses of epoxy coating.
Dynamics of dust explosion hazard indicators under physico and chemical effects on coal substance
Abstract
The effect of thermal action on coal was studied using the method of complex explosive and thermogravimetric tests. The dust of coal grades Zh and D was studied in the state “before the explosion” with subsequent comparison of similar indicators of dust “after the explosion”. The effect of multiple dust explosiveness has been established: post-explosive dust retains explosive properties and takes part in repeated explosions, which determines potentially dangerous zones for rescuers during emergency response. It has been established that a repeated dust explosion occurs when the LEL increases by approximately 2 times (for grade D coal from 43 g/m3 to 100 g/m3). The re-explosion pressure for dust concentrations close to the LEL (jt ≈ 100÷350 g/m3) is significantly lower than the initial value (≈ 6 times). As the dust concentration increases, the difference in pressure ∆P decreases and for jt ≥ 500 g/m3 the values of the pressures of the initial and repeated explosions are practically the same. The results were used in the regulatory document of EMERCOM of Russia, which regulates the collection of dust samples, the procedure for its study during rescue operations and during the investigation of technical causes of the accident.
Determination of human movement parameters when delivering fire extinguishers to the fire centre at water transport facilities
Abstract
The article presents experimental data on determining the delivery speed of fire extinguishers on ships. The unique feature of the experiment is the effect of the load (the fire extinguisher mass) on the movement speed of the participant.
Existing software products, techniques, as well as published materials do not take into account the influence of the mass and ergonomic characteristics of the fire extinguisher on the time of its delivery to the fire center.
During the experiment the intensity (heaviness) of physical activities was determined, the indicator of which was the heart rate. The analysis of the experimental values indicates that the lowest movement speed of the participants was recorded at the stages where agents had to go through doorways and at the initial stage when receiving a fire extinguisher.
The values obtained with the help of a heart monitor made it possible to determine the intensity of physical activities during the fire extinguisher delivery. It follows that the greater the mass of the fire extinguisher the higher the intensity of physical activity on the participant is, the heart rate increases, and, consequently, the speed of fire extinguisher delivery decreases. During the analysis of the experimental data, it was found that the movement speed of an agent with a fire extinguisher is influenced by the displacement of the center of gravity towards the load.
As part of the experiment, a projection in three planes was built for all participants, indicating the coordinates of the center of gravity both without a fire extinguisher and with fire extinguishers of different sizes. Based on the projection, the angle of deviation from the vector of the direction of movement was found. Due to the obtained experimental values of the movement speed with a load and the values of the deviation angles, the calculated movement speed of agents with fire extinguishers was determined, as well as correction coefficients characterizing the consideration of fire extinguisher mass, which was not taken into account when determining the center of gravity.
Based on experimental data there was determined the reference speed of the agent. Correction coefficients have been determined for each standard size of the fire extinguisher, taking into account the effect of the mass of the fire extinguisher on the agent. Obtained results can be used as reference data, in the form of correction coefficients, when modeling the movement of human flows. Obtained computational and experimental data will be used in the future to develop a unified integrated methodology for basic fire-fighting equipment on water transport. The complex methodology will take into account the layout concepts of a specific object (vessel), as well as the physiological characteristics of the crew involved in the struggle for the survivability of the vessel.
Development of fire test methodology with portable powder fire extinguishers with a charge of special purpose fire extinguishing powder
Abstract
Due to the specifics of extinguishing, the combustion process of active metals and metal-containing compounds occupies a special place among fires that occur at various facilities. Taking into account the fact that the technological processes of treatment and storage of this kind of fire load is mainly in enterprises of great state importance, the development and application of effective means to eliminate metal and metal-containing compounds from an early stage is highly relevant.
The main extinguishing agent, when extinguishing such fires, is a special purpose extinguishing powder that creates a protective layer on the surface of the burning metal. The means of extinguishing powder supply also plays an important role in the extinguishing process. As with other fire classes (A, B, C and E), fire extinguishers are used as primary means of extinguishing fires at the initial stage of development. Given that a fire extinguisher is used manually by a person in an emergency situation, it must have maximum reliability, which implies meeting certain requirements, the most important of which is the fire extinguishing capacity requirement. In the case with fire extinguishers designed to extinguish fires of metals and metal-containing compounds, there is currently a gap in the domestic regulatory literature, unlike the so-called “classic” fire extinguishers designed to extinguish fires of A, B, C and E classes. In view of this fact, an attempt has been made to find approaches to the development of model fires of metals and metal-containing compounds and methods of testing their extinguishing with portable fire extinguishers.
Experimental investigation of the technical characteristics of the ventilation duct fragment of the exhaust smoke ventilation system of the construction version of transport tunnels structurally combined with a deformation seam
Abstract
The article presents the problems of engineering systems that ensure fire safety in transport tunnels, in particular smoke ventilation systems. Taking into account the peculiarities of the architectural and structural design, transport tunnels are a source of increased threat to human life and health in the case of fire. At the same time, the efficiency of smoke ventilation systems directly depends on the design of the components and assemblies of these systems (fans of supply and exhaust systems, ventilation ducts, fire valves, etc.), as well as on their interaction with each other.
Also, the article considers the need to study the behavior of duct structures of exhaust smoke ventilation systems in construction used in transport tunnels, their compliance with the requirements of regulatory documents. The relevance of the article is that the problem of the technical design of ventilation ducts of construction design in road tunnels has not been studied properly, which may adversely affect the functioning of smoke ventilation systems in general.
In addition, the article provides an analysis of an experimental study of a ventilation duct fragment of a construction version of an exhaust smoke ventilation system of a construction version of transport tunnels structurally combined with a deformation seam (hereinafter referred to as a fragment of a ventilation duct with a deformation seam). The dictating characteristic during the experiment was the tightness of the sample, characterized by the tightness class “B” according to SP 7.13130.2013. The test sample was mounted on a special stand, in accordance with the established technical characteristics. During the experiment the sample was subjected to a double effect: the creation of a temperature test bench in the fire chamber according to GOST 30247.1; creating the maximum possible pressure drop on the sample. During the experiment, the maximum condition of the sample for tightness was reached at 45 minutes. The obtained results of the experiment indicate that there is a further need to study the behavior of ventilation duct structures of construction design in a tunnel ventilation system under thermal influence, in order to increase their fire-technical characteristics and to improve the efficiency of smoke ventilation systems as a whole.
Experience Exchange, Problems and Judgments
Analysis of the problems of using mobile robotic tools in extinguishing fires at facilities of the fuel and energy complex and the formation of ways for their further development
Abstract
The article is devoted to application of robotic tools for fire extinguishing at the facilities of fuel and energy complex. The fires at these facilities and the problems that arise during their extinguishing are analyzed. The analysis of fires has shown that nowadays the situation at fires at the objects of fuel and energy complex is aggravated, when the fire development occurs as a result of artillery shelling and attacks of unmanned aerial vehicles, as a result of which a number of forces and means of firefighting units and elements of autonomous firefighting system of tank farms can be out of order, and the usual tactics and methods of firefighting are difficult to perform in practice or impossible to perform, due to the destruction of the infrastructure of the object. There is considered the experience of creating robotic means in Russia and in foreign countries, as well as the problems arising in firefighting with the use of robotic means. The problem of lack of samples with supervisory control and a number of technical problems on their realization is revealed, in particular, there is not solved the issue of static stability of robotic means, especially in the remote control mode. For the first time the problem of high error of foam dosing systems and, as a consequence, increased consumption of foam agent and obtaining foam of low extinguishing power is outlined. The complexity of providing robotic means with uninterrupted supply of fire extinguishing agents, as well as the lack of the possibility of laying a hose line in automatic mode, for long distances is analyzed. The ways of solving the problems arising in fire extinguishing with the use of robotic means are proposed. The question of planning and supply of extinguishing agents by robotic means to the combustion zone is considered. Calculations of extinguishing a conditional fire in a tank at an oil depot with the use of robotic means are carried out. The relevance and expediency of robotic means application is determined and the ways of further improvement of robotic complexes systems on the basis of experiment and calculation indicators are proposed in order to increase the efficiency of their application.
Analysis of the dynamics of the fire hazards spread into the windows of ordinary stairwell in a residential building serving as a fire-safe area
Abstract
Regulatory documents in the field of fire safety provide for the possibility of using standard stairwells in residential buildings as fire-safe areas. However, there are no regulatory requirements regarding the width of the piers between stairwell windows and the windows or balconies of rooms adjacent to the stairwell. Additionally, there are no requirements for the dimensions of stairwell projections relative to the building facade that could restrict the spread of fire along the facade into the stairwell windows. To justify the absence of these requirements, there was conducted an analysis of the dynamics of fire hazards into the windows of ordinary stairwell from the windows and balconies of burning rooms. This analysis was supplemented with results defining time intervals for evacuation and rescue operations by fire departments.
Topical issues of fire safety of electrical installation devices
Abstract
The Institute has repeatedly informed readers in its publications about the high fire hazard of electrical wiring (EW), which traditionally leads among other types of electrical installations in the number of fires (in 2023 – 77.89 %), direct material losses from them and the number of people killed in fires.
The second place among electrical products in terms of the same indicators is occupied by electrical installation devices (EID): plug sockets, switches, changeover switches, etc. Although EID are not included in the standardized term [1] “electrical wiring”, they are functionally very closely related to each other at facilities, since the conductors of cable products of electrical wiring are directly connected to the contact clamps of EID. As studies show, the fire hazard of electrical installations is mainly associated with an increase in the contact resistance in the contact connections during operation (“poor contact”) followed by their heating, up to the ignition temperature of the base material of the electrical installation on which the contact clamps are fixed, or the ignition temperature of the insulation of the connected conductor.
This was particularly prevalent in EW consisting of cable products with aluminium conductors, prompting regulatory restrictions on their use in the 1990s.
However, the urgency of the problem of reducing the fire hazard of contact connections has increased again since March 2019 after the Government of the Russian Federation decided to use cable products with conductors made of aluminum alloys at facilities in electrical installations.
The article analyzes the results of experimental studies to assess the contact connections of switches and sockets (the most widely used in electrical installations) in connections with conductors made of aluminum alloys for their compliance with current regulatory documents.
Analysis of violations of fire safety requirements committed at the stage of design and building of capital construction facilities
Abstract
In order to improve the Federal State Fire Supervision there were carried out an analytical review of the provisions of the regulatory legal acts of the Russian Federation and regulatory documents on fire safety, as well as an analysis of violations of fire safety requirements committed at the stage of design and building of capital construction facilities (including by functional fire hazard classes).
Based on the obtained results, there were prepared conclusions on the feasibility of the participation of specialists from the state fire supervision authorities of EMERCOM of Russia in the expert examination of the design documentation of buildings (structures) for compliance with fire safety requirements, as well as in the issuance of a building permit and commissioning of the protected facility.
Material consequences of fires in the context of socio-economic development of Russia
Abstract
During the period of reform of all aspects of public life, interest in statistics, including fire statistics, will inevitably increase. The nature of state fire statistics and the main directions of its development are inextricably linked with the history of the country and were largely determined by the tasks and methods of managing fire safety. The article focuses on the problems of determining material damage from fires in the context of socio-economic development of Russia. Fire statistics, in addition to careful data accounting, are designed to provide a comprehensive analysis of statistical materials in order to identify risks and find ways to better ensure fire safety. Accuracy and correct interpretation of statistical data, which characterise the conditions and results of functioning of the State Fire Supervision bodies, allow making balanced management decisions.