Introduction. The use of fireproof tent fabric at children’s tent camps remains a relevant problem. It may be resolved by developing a special flammability assessment methodology and criteria applicable to materials, used as the structural framework of tents. This solution will determine the choice of fabric.

Aims and purposes. Materials, currently used to make tents, include natural or synthetic fabric and various polymers, that may be a fire hazard. In case of fire, safe evacuation of people may be unfeasible, although it is particularly important for children’s seasonal tent camps designated for sports and leisure.
Domestic regulatory documents, that are currently in force, contain solely general technical requirements applicable to travel tents or ensuring fire safety in the territory of children’s tent camps, but there are neither fire safety requirements applicable to tent materials, nor any methods of their assessment. Meanwhile, there were cases of fire at children’s tent camps.
The purpose of this work is to establish fire safety requirements applicable to tent materials used at children’s tent camps, to develop their testing criteria and methodology.
The main objectives to be accomplished in order to achieve the pre-set purpose include the analysis of effective regulatory requirements and methods used to determine the flammability of tent materials, the establishment of parameters and criteria designated for their assessment and the development of a standard testing methodology.

Results and discussion. Experimental studies were carried out to assess a set of flammability-related parameters of several types of fabric and polymers used to make outer/inner tents and ground sheets. It has been determined that currently used materials are fire-hazardous; therefore, it is advisable to limit the production of tents from combustible and flammable materials whose combustion may be triggered by low-calorie ignition sources, including those that can melt or release toxic combustion products.
Currently used standard methods were applied to develop modified methodologies and classification criteria needed to assess the flammability of tent materials for children’s summer camps; experimental studies were also carried out.

Conclusions. A draft national standard has been developed; it implies the establishment of the flammability assessment methodology and criteria and restricts the use of tent materials, that are extremely hazardous in terms of the toxicity of their combustion products.

Introduction. Problems of fire safety of dangerous goods (DG) in the process of their rail transportation have not been fully resolved. The flammability assessment of substances and materials is insufficiently impartial; an integrated indicator, that allows to apply a consolidated methodological standpoint to improve their energy efficiency and environmental/fire safety is unavailable.
The purpose of this work is to substantiate the feasibility and advantages of the exergy approach to assessing the fire hazard of the exhaust gas emitted from railroad transport.

Materials and methods. The use of the flammability potential as an integrated indicator of the fire hazard of cargoes has a number of limitations. The exergy approach has a strong potential if applied to the assessment and prediction of fire hazards. Present-day and potential railroad cargoes serve as examples that substantiate the feasibility of this approach.

Results and its discussion. Dependences between fire hazard indicators (flash points, flame propagation limits, auto-ignition points, heat of combustion) demonstrated by the components of liquid and gaseous fuels and the chemical exergy were identified.
A study of changes in the physical exergy triggered by spills and combustion were illustrated by liquefied natural gas and liquefied hydrocarbon gases having various compositions. Physical exergy change patterns depending on the temperature and pressure of the above products were developed.
For self-ignitable cargoes, dependences between the physical exergy and activation energy, critical ambient temperature, and heat capacity of self-heating materials were identified. The influence of thermal conductivity and humidity coefficients on the exergy value is established.
Exergy changes were determined depending on the elemental composition of solid municipal waste, ash, volatile matter and fixed carbon content. Polymers and rubbers have the highest values of this indicator.
An exergy indicator was introduced to assess fire and environmental hazards of substances and materials; it serves as the basis for the classification of cargoes.

Conclusions. The use of the exergy indicator allows to increase the objectivity of assessments and take account of technical, economic, environmental criteria and indicators of fire hazards within an integrated system.

Introduction. Screens often surround openings in the floor slabs of atrium buildings to prevent the spread of fire hazards to higher floors and to improve the efficiency of smoke ventilation systems. In this article, the co-authors assess the expediency of installing screens around openings in the floor slabs and identify the best screen height values. In this article, the co-authors perform a quantitative analysis of the ability of screens to prevent the propagation of hazardous fire factors, to identify general regularities typical for a multi-level space, and to develop recommendations for the installation of screens inside public buildings. The co-authors suggest that screen height should be a solution to the following tradeoff problem: the use of screens reduces acceptable evacuation time for the floor that has screens installed and rises the evacuation time for higher floors.

Rational screen height selection algorithm. The co-authors propose the following algorithm for the two-stage selection of the rational screen height. At the first stage, the evacuation problem is resolved. As a result, evacuation completion time is determined for emergency exits. Further, acceptable evacuation time and the time needed to block emergency floor exits are identified for a particular type of a fire alarm system.
At the second stage, the dynamics of hazardous fire factors in building rooms is assessed for various screen heights. As a result, the rational height of screens is established for the evacuation time to remain positive.

Conclusions. Screen height values cannot be determined in advance. Each case requires an individual approach that entails the resolution of evacuation problems and the tracking of the dynamics of hazardous fire factors in buildings that have multi-height spaces. These ideas are in line with the concept of flexible regulation of fire protection systems designated for construction facilities.

Introduction. Сases of ineffective activation of automatic sprinkler fire-fighting systems (AFFS), designed pursuant to current standards, have made it necessary to address the following three issues: a) identification of reasons for ineffective activation; b) examination of AFFS systems to ensure their successful activation in case of fire; c) making a list of recommendations for AFFS designers. These issues can be resolved with reference to Appendix B to new SP (Construction Regulations) 485.13130.2020.

Maximal critical height of sprinkler placement. Models of fire development were used to design the roof height limit and the AFFS bulb heating time. If the ceiling height exceeds the limit value, sprinklers cannot be activated in a timely manner. This leads to delays in the AFFS activation, and, as a result, the fire area exceeds the one safeguarded by the sprinkler.

Acceptable sprinkler height. The analysis of fire scenarios and bulb heating models allows to more accurately project the feasibility of timely AFFS activation. This, in turn, allows to solve the three above listed problems.

Using a differential heat detector to activate sprinklers. If it is established that the use of the AFFS, activating sprinklers by means of thermal destruction of a bulb, is ineffective in a given room, the feasibility of forced AFFS activation using a differential heat detector responding to the temperature rise in a room may be considered. The ratios, thus obtained, are applied to identify the acceptable height of premises protected by the AFFS equipped with such detectors. Problem solutions, including the identification of the reason for the ineffective operation of the AFFS, examination of the AFFS in operation, and provision of recommendations to designers, are demonstrated using the exhibition hall as an example.

Conclusions. The above-mentioned problems are resolvable with the help of Appendix B to new Construction Regulations 485.13130.2020 and the above models.

Introduction. A number of problems accompany the development of new extinction methods applicable on the premises of buildings and structures and the use of advanced fire extinguishing agents. Subject-specific studies are needed to solve these problems. They include the identification of general principles of fire extinguishing efficiency and further development of the optimal mode of application of firefighting agents. The purpose of this work is the theoretical assessment of fire extinction mechanisms involving the water mist applied to combustible liquids. The objectives to be accomplished include the equations based on the mass/energy conservation laws and derived for flame zones with account taken of the water mist applied; the assessment of the water flow rate for different combustion mechanisms; comparison of assessment results with experimental data obtained in the process of extinguishing model fire seats that have burning combustible fluids.

Methods of analysis. The calculations involve the equations based on the mass/energy conservation laws and derived for flame zones above the surface of combustibles.

Research results. The author analyzes two fire extinguishing mechanisms that contribute to the suppression of burning in the flame zone: 1) the attainment of the value of mass concentration of water vapour that reaches the lower concentration limit of combustion of the combustible mixed gas (oxygen reduction); 2) cooling combustible mixed gas in the flame zone by evaporating water until the flash point temperature of combustible vapour is reached.

Conclusions: Equations based on mass/energy conservation laws were derived for flame zones, formed in the course of combustion of flammable liquids, with account taken of a jet of water mist. Water flow rates needed for the implementation of various extinguishing mechanisms were analyzed using the proposed equations. Theoretical results were compared with the experimental data obtained in the process of using water mist to extinguish model fire seats that contain combustible fluids.

Introduction. One of the main problems of fire extinguishing at gas compressor stations is fires in confined spaces where electrical installations can be under voltage. To extinguish these fires, the co-authors propose to use jets of thermally activated water containing salts that inhibit burning. It is necessary to assess the electrical conductivity of water jets to prevent the exposure of fire-fighting units to electrical injuries.

Materials and methods. In the experimental study, the principal electricity measuring instrument is digital dc megaohmmeter M4122U, which takes readings if operated from a laptop. The flow rate was measured using IT 2518 measurement complex and TDR14–2–3 primary flow converter of the turbine type. Termit T-35 hardness converter performed electromagnetic water treatment.

Theoretical fundamentals. Measurements of leakage currents in jets of thermally activated water, fed through fire nozzles mounted onto a multi-purpose fire truck, were taken, and the maximum permissible distance to an electrical installation was determined experimentally and analytically using an experimental stand.

Results and discussions. Averaged values of resistance of a jet of thermally activated water fed from a long-range nozzle at control points do not leave the confidence corridor with a probability of 0.95, which means that they do not cause a significant change in dc resistance. Inhibiting salt, injected into the water, reduces the resistance of jets of thermally activated water by no more than 2–3 % compared to under-heated water. The treatment of the inhibiting salt, injected into the under-heated water, using Termit T-35 hardness converter, does not significantly change the resistance of thermally activated water jets.

Conclusions. It is theoretically and experimentally proved that the injection of inhibiting salts into the underheated water, as well as the electromagnetic treatment of water using low-power stiffness converters, do not significantly affect the electrical conductivity of jets of thermally activated water if compared to jets that contain no inhibiting admixtures. The extinguishing of surfaces of electrical installations using jets of thermally activated water containing flame inhibiting injections of salts, as well as the development of an inerting concentration in confined spaces of gas compressor stations is electrically safe for any person engaged in fire extinguishing.

The article addresses the problem of mainstreaming the state regulation of the technosphere in terms of fire safety assurance and urban development.
The technosphere, being an artificial structure created by humans willing to simplify and protect their living, has turned into a major problem rather than a benefit over the last fifty years. Accelerated sociocultural evolution is the reason for this change.
Reason 1 is our poor knowledge of the technosphere and its constituents that we are still willing to create and apply using our simplified (conventional) ideas about the natural processes underlying their creation and application.
Reason 2 is the logistic breakdown of the technosphere, as a result of which the consolidated sociocultural space is regulated by separate social norms focused on minor fragmented goals, determined by subjective needs of small groups willing to obtain immediate benefits.
Reason 3 is decelerated development of the social environment that lags behind industrialization and urbanization. Thus, it is unable to exercise reliable control over the safety of the technosphere.
A set of actions, aimed at the expansion of the area exposed to social control and the tightening of penalties represent a practical solution to these problems that is currently applied by executive government authorities.
However, social regulation quality improvement, based on the principle of prevention of inacceptable social harm, has been disregarded.
The introduction of a risk oriented model into fire safety assurance and urban planning is analyzed in an attempt to consider the problems in question.

 

The article addresses the general principles that govern the selection of wires and cables for hazardous areas. The analysis of effective regulatory documents, governing the use of cable products in hazardous environments is performed. The information on safe wiring methods is provided. Examples of cable grades, that comply with the wiring standards applicable to fire hazardous areas, are provided, as well. Clarifications on the procedure for selecting heating cables for cable heating systems in the areas, accommodating explosive mixtures, are offered.