Vestnik of the Institute for Command Engineers of the MES of the Republic of Belarus

Fast-curing polymer foams for the limit of spread and extinguishing of fires

2020-01-15T11:42:46+03:00

Purpose. The results of researches of influence of system retardants on physical, chemical, fire-blocking and fire-extinguishing properties of the composite material is based on expandable polyurethane foam brand «Izolan-125», which is a promising material as agent limits the spread of fire on cable mines civil buildings, as well as the fire-extinguishing agent for extinguishing fires of different classes.

Methods. In research were used: method of complete factorial experiment, the method of differential scanning calorimetry, complex thermal, spectrophotometric and variance analyses, electron microscopy.

Findings. This paper presents new experimental data on the development and adjustment method of full factorial experiment of the formulation of retarder burning, thereby creating a flame retardant rigid polyurethane foam brand «Izolan-125» with a satisfactory reactivity and physical and chemical properties. In a series of laboratory, installation and field tests showed the presence of flame retardant effect, flame retardant polyurethane foam to limit the spread of fire in cable mines civil buildings.

Application field of research. The obtained experimental data on the mechanism of action of the investigated retardants allow a directed approach to the development of flame retardants for polyurethane foams of different brands.

Conclusions. Designed in flameproof polyurethane foam material is relatively smaller unit costs of other extinguishing agents, indicating a higher fire-extinguishing efficiency. Together with the advantage of condensed foam in comparison with liquid formulations is its high dielectric characteristics, which opens the possibility of applying the flame retardant material designed to extinguish fires that cannot be extinguished with water and water-based formulations.

Autoclaved aerated concrete fire resistance based on stress-strain diagrams after high heating

2020-01-15T11:44:17+03:00

Purpose. The paper is devoted to experimental study data of autoclaved aerated concrete stress-strain diagrams after high heating and fire resistance evaluation.

Methods. The specimens of autoclaved aerated concrete were heated in muffle furnace and tested at breaking machine. The results were analytically discussed and fire resistance evaluation technique pro-posed.

Findings. The autoclaved aerated concrete stress-strain diagrams after heating are found. Shrinkage rate depending on temperature is determined. The fire resistance evaluation technique is proposed. Research application field. The obtained experimental study data could be used in fire resistance design of autoclaved aerated concrete structures.

Conclusions. Fire resistance design of autoclaved aerated concrete structures should include stress-strain diagrams after heating study jointed with shrinkage rate.

Warming simulation for autoclaved aerated concrete structures at fire conditions

2020-01-15T11:46:15+03:00

Purpose. The paper is devoted to experimental study data of autoclaved aerated concrete warming simulation at fire conditions.

Methods. The specimens of autoclaved aerated concrete were heated in flaming machine and muffle furnace. Full-scale fire experiment was planned and conducted. The results of experiments were discussed.

Findings. The autoclaved aerated concrete structures have low thermal conductivity and high shrinkage rate at fire. The behavior and finite-element model for local destruction of autoclaved aerated concrete walls with steel stiffening elements was obtained. It is not recommended to use steel stiffening for fire walls and partitions.

Application field of research. The obtained experimental study data could be used in fire resistance design of autoclaved aerated concrete structures.

Conclusions. Fire resistance design of autoclaved aerated concrete structures should include heating study jointed with shrinkage rate, as far as adjacent elements behavior at fire.

Determination of the fire resistance of prestressed concrete slab with unbonded reinforcement

2020-01-15T11:47:53+03:00

Purpose. The article is dedicated to features of determination of the fire resistance of prestressed concrete slab with unbonded reinforcement.

Methods. The fire test concrete slabs with unbonded reinforcement of the fire resistance.

Findings. The probability of occurrence of fragile destruction of prestressed concrete slab with unbonded reinforcement of the compressed zone is considered. The fire resistance limit of prestressed concrete slab with unbonded reinforcement and critical temperature for reinforcement are determined. Inverse problem on determination of fire resistance defined the critical temperature for reinforcement. The schemes of slabs destruction are reviewed.

Application field of research. The obtained experimental study data could be used in calculation and design of prestressed concrete slab with unbonded reinforcement.

Conclusions. The scheme of destruction of test samples meet the standard scheme of destruction of prestressed concrete slabs with unbonded reinforcement, while the rate of destruction is much higher and the critical temperature of reinforcement is much lower. For prestressed concrete slab with unbonded reinforcement by fire effect is typical strong brittle fracture in the compressed construction zone. As the brittle fracture can’t be avoided in view of the specific of structures, it is necessary to apply the constructive solutions for the protection of the protective concrete layer.

Methodology of fire resistance evaluation of steel columns with fire structural protection, located on the perimeter of the premises

2020-01-15T11:49:10+03:00

Purpose. The paper is devoted to engineering method for structural steel columns with fire protec-tion for two- and three-sided fire exposure fire resistance design, with regard to the warming up of steel caused by the destruction of adjacent walling.

Methods. Based on full-scale fire research the method of steel columns with structural fire protection warming up was improved, set around a premise (building).

Findings. The method of steel structures warming up, using the elementary heat balance mathematical model was developed. The technique was worked out and full-scale fire research of structural fire protection and adjacent structures mutual interaction was conducted. Research application field. The obtained experimental and theoretical study data could be used in fire resistance design of steel structures with structural fire protection.

Conclusions. The steel warming up factor for columns with structural fire protection due to the adjacent walling destruction was revealed.

Peculiarities of mathematical models' creating for the road tanks at simulations of their dynamics

2020-01-15T11:50:21+03:00

Purpose. The paper analyzes the principles of mathematical models' creating for the road tanks allowing to facilitate the results' interpretation and to decrease the time spent on computations.

Methods. Analysis of liquid cargo oscillations in the tank reservoir was performed with the use of the equivalent rigid body model, coupled with the reservoir by the viscoelastic element. The dynamic equations for the motion of a system of bodies were composed taking into account the characteristics of friction in the brake system and the possibility of slippage between the wheels and the road.

Findings. It was established taking into consideration the mass of the wheels and spring deformations do not lead to the significant increase in the accuracy of the kinematic and dynamic parameters calculations for the case of the road tank braking. It was confirmed the earlier detected effect of changing modes of wheels rolling with and without slipping for the case of automobile emergency braking.

Application field of research. The obtained results can be applied for improving the braking systems of road tanks, as well as for the drivers' training in safe driving.

Conclusions. Rational simplification of computational models allows to implement the optimization calculations at tanks' analytical and computer models development in order to ensure the best operational properties of the road tank partially filled with liquid.

The analysis of thermal exchange in the cabin of the fire fighting vehicles at external thermal influence

2020-01-15T11:51:34+03:00

On the basis of the analysis of heat-exchanging processes in car cabin under the influence of heat fluxes of the fire the mathematical model of heat exchange of geometrically closed system with environment is offered. The program is made for the numerical solution of task of non-stationary heat exchange. The program allows to vary over a wide range properties of elements of walls and external conditions for choice and assessment of efficiency of technical means of providing safe microclimate in cabin of fire fighting vehicles.

Calculation of time of evacuation of people using the forecasting method based on use of molecular descriptors and artificial neural networks

2020-01-15T11:54:44+03:00

For calculation of time of evacuation of people, according to the technique stated in GOST 12.1.004-91 such fire-dangerous indicators of substances are necessary: specific mass speed of burning out, linear speed of distribution of a flame, the lowest warmth of combustion. In most cases basic data in reference and standard books are absent. In such cases it is recommended to use the substance parameters similar on a structure to initial substance. In such results there is a big error which doesn't provide an integrated approach to development of the system of prevention of the fire. For optimization of a choice of the actions aimed at providing fire safety it is offered to use the forecasting method based on use of molecular descriptors and artificial neural networks. By means of a method, the absent parameters for a dipropilketon were predicted. As a result of approbation of this approach by calculation of time of evacuation of people on the example of limit ketones of the dipropilketon and benzene which is a part of the first calculation was carried out. Comparing the received results, it is visible that impact of dangerous factors of the fire on the person come in case of use of the predicted values that provides more rigid approach in ensuring fire safety. GOST 12.1.004-91 technique in a complex with the forecasting method based on use of molecular descriptors and artificial neural networks I proved from a positive side and allows to time evacuations of people with the acceptable accuracy.

Sensor efficiency improvement for smoke detectors

2020-01-15T11:55:49+03:00

Were analyzed the ways to improve radioisotope and linear optical fire alarm systems, designed to sense smoke. Were offered modifications of the basic construction schemes of such detectors, providing the improvement of their sensor efficiency. Special attention was paid to ecological safety of radioisotope smoke detectors.

Research of water-foam nozzles characteristics in various modes of extinguishing agent discharging

2020-01-15T11:57:54+03:00

Purpose. The objective of the research is to analyze the influence of nozzle diameter, grid presence, grid cells area and number of aeration holes on the parameters of sprayed water jet formed by water-foam nozzle and to define performance characteristics of the water-foam nozzle.

Methods. Prototypes of water-foam nozzle were tested on water flow, jet range, effective jet range, spray angle and average sprinkling intensity.

Findings. Influence of nozzle diameter on water flow and spray jet parameters is determined. The necessity of installation of grid with 1 mm2 cells into tested water-foam nozzle is proved. The appropriate number of aeration holes for tested nozzle is defined. Application field of the research. The obtained experimental study data could be used in fire nozzle design.

Conclusions. The prototype with 11 mm nozzle diameter, 1 mm2 grid cells and 5-7 aeration holes is the most optimal version for discharging water. It has better performance characteristics than a regular nozzle.

Calculation of the necessity of forces and means of civil defence for elimination of the consequences of emergency situations occurring (occurred) in zones of destruction

2020-01-15T11:40:09+03:00

Purpose. Calculation of the necessity of forces and means of civil defence for elimination of the consequences of predicted emergency situations occurring (occurred) in zones of destruction. The article deals with the development of the methodology of calculation of forces and means of civil defence. The object is forces and means of civil defence. The subject is the order of using forces and means of civil defence.

Methods. While carrying out the study the methods of mathematical analysis and synthesis, and the method of expert estimation were used.

Findings. At the moment in our country there are no methodological recommendations defining the order of the determination of the necessity in forces and means of civil defence for elimination of the consequences of emergency situations occurring (occurred) in zones of destruction. .

Application field of research. The methodology of the calculation presented in the recommendations gives the possibility to get generalized quantitative characteristics of forces and means of civil defence for solving specific tasks of elimination of the consequences of emergency situations in zones of destruction basing on minimum initial data.

Conclusions. Given methodological recommendations can be also used while performing operational calculations of necessity of forces and means of civil defence during search and rescue operations and other emergency actions in zones of destruction.

Psychological messuring of information and education activity in units and subunits for emergency situations

2020-01-15T12:00:42+03:00

Purpose. The article is devoted to the psychological aspects of the activities of the MES in the sphere of life safety education.

Methods. Announced problematic is considered basing on systemic approach, totality of general logical methods, methods of semantic and discourse-analysis, and psycholinguistic tools.

Findings. According to the systematisation of methodical base of interaction of units and subunits for emergency situations with mass media and the population the essential channels of such interaction have been determined as well as conceptual approaches to this interaction. Research application field. The results of the research can be used: while working out and optimization of methods of informative and propaganda work in the sphere of national safety; while preparing fundamental, generalising and training works on psychological aspects of personal safety; while organising scientific research in the sphere of labour psychology, as well psychology of mass communication.

Conclusions. Tools for the analysis of social activity in the sphere of prevention and elimination of disasters have been developed, qualitative and quantitative characteristics of this activity have been determined.

International experience in organizing psychological aid to victims of emergencies

2020-01-15T12:02:18+03:00

The overview of international experience in organizing psychological aid and protection of the population has been provides. Examples of organization psychosocial care and support in the United States, France, Latvia, Kazakhstan, Russia, Belarus and Ukraine give opportunity for analysis and comparison of regulatory impacts state regulation on the provision of psychosocial assistance in emergency. Found that the determining factors of State influence are the conceptual foundations of the construction and functioning of public organizational and managerial systems of civil protection, and the level of cultural and psychological development of the country’s society. Analysis of the advantages, issues normative, institutional and administrative decisions gives the opportunity in later to adapt the most interesting and useful examples of regulatory impact. Borrowing positive experience of different countries can be quickly and cost-effectively improve similar activities for own country and to predict trends in the subsequent development of this directions.

Helplessness as a professional lifeguard destruction of rescuer

2020-01-15T12:03:43+03:00

The article presents the main theoretical approaches to the study of the concept of learned helplessness personality rescuer. The factors influencing its formation. Formulated the concept of learned helplessness in the context of personality psychology lifeguard activity in special conditions. Defined the concept of learned helplessness as a professional destruction personality lifeguard generalized theoretical approaches to the understanding of learned helplessness, and discloses the psychological characteristics of learned helplessness rescuer. Large influence on the personality lifeguard psycho-emotional stress, creates psychological discomfort, initiates professional lifeguard maladjustment. All this leads to the fact that some rescuers passivity, indifference and colleagues affected by the emergency, lack of initiative and apathy generating occurrence of learned helplessness. Interest in the phenomenon of learned helplessness, as a professional lifeguard degradation is a specific response to the uncontrolled growth of events and difficult situations faced by a lifeguard. Study enriches the idea of learned helplessness as a professional lifeguard destruction of personality. Learned helplessness - a professional destruction of personality, formed in the course of professional activities as a result of repetitive traumatic events, difficult situations that lifeguard perceived as uncontrollable and unable to solve.