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Pozharovzryvobezopasnost/Fire and Explosion Safety

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Vol 25, No 9 (2016)

QUESTION - ANSWER

GENERAL QUESTIONS OF FIRE SAFETY

13-21 497
Abstract
The article summed up the activities of employees of the Saint Petersburg University of State Fire Service of Emercom of Russia in the part of works on creation of new projects and improving institute of effective normative documents in the field of fire safety. According to the results of research and theses there are proposed: a) drafts of set of rules and the Annex to GOST R 22.7.01-99 by definition of a rational number of work stations and lines of communication in the change dispatching system; b) draft Annex to set of rules 11.13130.2009 by definition of the locations of fire departments in the regions and adjustment of areas of departure; c) proposals on revised calculations of hydraulic networks of outdoor and indoor fire water supply system, and automatic installations of fire extinguishing; d) study on the development of rules of checking the fire safety of rail transport and changes in set of rules 153.13130.2009 in terms of fire safety requirements for railway transport infrastructure; e) draft of guidelines on actions of the operational units in extinguishing fires and conducting rescue works in Zoological parks. The adoption and use in practice the proposed changes to the regulatory framework of fire protection will reduce the risk of fire and impact hazards to securable objects and people. An important feature of the development is to maximize accessibility for a wide range of experts in the field of fire safety. To this end, developed draft of set of rules and applications to existing standard NYM documents were provided with examples of calculation. The main provisions of the developed methods were used in the educational process of the university, regularly published (including in the journal “Pozharovzryvobezopasnost”) and were reported on international and departmental conferences. This allowed us to take into account the comments and suggestions of specialists.
22-29 417
Abstract
There are considered issues concerning contractual relations between organizations, which operate hazardous production facilities and emergency rescue services and units. 177876 fire accidents are amounted on an average in the Russian Federation annually and about 14586 people die by fire. An economic damage amounts to 10823 mln rubles. The manufacturing enterprises are the most hazardous. One of the main ways of ensuring fire safety is improving of contractual work in manufacturing enterprises as above, and as well in emergency rescue services and rescue units. In spite of the freedom of contract in the civil law, a making a contract for rescue operations is an absolute requirement for all hazardous production facilities. The ways of solving the problems that arise during the conclusion and executing of an agreement for carrying out the emergency rescue operations incidental to firefighting, between manufacturing enterprises operating hazardous production facilities and between emergency rescue services and formations are studied. In case of drawing up of contractual relations, the contract is required to define the emergency rescue operations as the subject of a contract with compulsory specification for this type of work as fire extinguishing. It is allowed to make a separate contract for carrying out emergency rescue operations, concerning fire extinguishing. Emergency rescue services and formations, state and non-state, acting as a contract acceptor, have to be certified for this kind of work. Otherwise the contract will not meet the requirements of current legislation. An important requirement for passing the certification is the training of employees of emergency rescue services and formations. The absence of certification is the reason for termination of contract for carrying out emergency rescue operations, connected to fire extinguishing. Emergency rescue formations have to be ready to respond to emergencies and conduct work to neutralize them. In the case of their unavailability to respond to emergencies and conduct work to neutralize them, as well as the inability to maintain organizations under contracts and be involved in carrying out emergency rescue operations, counterparties of these formations have a right to terminate the contract for carrying out emergency rescue operations, connected with fire fires. It is shown that the solution of these problems will improve the fire safety of organizations, operating hazardous production facilities.

FIRE SAFETY OF BUILDINGS, STRUCTURES, OBJECTS

52-59 396
Abstract
At the organization of material support of forces and means of Emercom of Russia being engaged in liquidation of consequences of emergency situations an important role plays the task of selecting, on the one hand of the safest, and on the other hand - possible economical routes on which to perform the supply of material resources for the purposes described above. At the same time (it is very important) the safety performance indicators of roads are not clearly defined a priori. In order to overcome this uncertainty in the source data it is proposed to use the theory of fuzzy sets and fuzzy logic. The article contains a brief summary of the provisions of the branches of mathematics required to solve this problem. The main result of this work is to develop two approaches to assessing the reliability of the plans of supply of material resources to the forces and means of Emercom being engaged in liquidation of consequences of emergency situations. The reliability of a road is proposed to characterize by the truth value of the statement “the road is reliable”, the reliability of a supply plan of material resources refers to the minimum of the reliabilities of routes used in this plan. The reliability of a route is the minimum of the reliabilities of roads, of which the route consists. The specified technique of calculation of reliability of routes and the entire plan is based on the definition of the conjunction of fuzzy statements. To determine the reliability of a road two approaches are considered, which are associated with the calculation of the value of the output indicator “reliability” using the known values of the input parameters. The first indicator - “protection” is measured by the number of the Traffic Police posts of on 100 kilometers of road, and the second “viewing distance” is the average distance at which a side of the road is viewed. In the first approach the output value is considered as a convolution of the input that is performed using the ideas of the theory of vector optimization and ideas of Zadeh and Bellman. The second approach is based on the method of Mamdani fuzzy inference. Here, for given values of the input indicators it is constructed a membership function of the output, provided that the input took the specified values. Obtained by converting a fuzzy set into a crisp number the value of the output indicator is proposed to use as reliability characteristics of the road. In conclusion a relatively simple algorithm is given for selecting the most reliable plans of supply of material resources to the forces of Emercom of Russia and among them of the most cost-effective plans.
60-69 464
Abstract
The problem of improving the safety and sustainability of transport in emergency situations holds a special place in the national security of the state. With transport enterprises there are associated state interests such as territorial integrity, the unity of economic space, provision of external economic relations of Russia and its integration into the global economic system. The study showed that in the field of risk management through extremely situations (ES) on the transport it’s situation, when the systematization and deepening of knowledge is extremely difficult without specifying of the conceptual foundations of the theory of risk management and ensure its semantic content in line with the true essence of display of the phenomena of risk management. Moreover, the question of risk management have not been sufficiently formalized and structured risk management model demand development. Here it should be recognized that the study of tools of emergency risk management on the transport, so far not received adequate attention. As a result of the situation, when the existing set of theoretical propositions for risk management of emergency on transport could not determine how to operate effectively in the new environment, and the practice of risk management is largely insufficient. These circumstances caused the act-almost, goal and objectives of the study. The purpose of this study is to develop new, and adapt existing instruments of risk management of emergency transport to improve the efficiency of transport enterprises (TE). To achieve this goal the following tasks were accomplished: 1. The mathematical measure of preventing a terrorist act based on the selection of the most probable places and the method of implementing the attack, as well as establishing a sufficiently adequate model of the intruder, i. e. parameters describing the size, capability and readiness of terrorists. 2. The approach to risk assessment of ТЕ based on the application of the method of data fitting and the method of expert estimations. 3. The proposed use of modern technology, broadening the range of instruments to prevent emergency situations and characterized by the use of: scanning objects; preventive measures; control of objects on the ТЕ; inform on actions in case of emergencies. Theoretical and methodological basis of research is works of domestic and foreign scientists on risk management, regulatory - legal acts of the Russian Federation, methodological developments in the field of management of transport enterprise in the conditions of uncertainty. During the research used the general scientific methods and methods of system analysis, mathematical and statistical methods, sources on the Internet, impact of research of the consulting companies in the field of risk management, the empirical and calculated data, obtained by the author. The theoretical significance of research results is development of theoretical positions on the risk management of emergency situations on transport in the modern conditions. Developed findings expand the theoretical base of this research area and can be used in further scientific developments in the field of risk management. The practical significance of the study is to create tools to improve the effectiveness of risk management of emergency situations on transport. The tools can be used for further scientific studies of, in curricula of universities and training courses management training.

FIRE SAFETY OF PEOPLE

70-77 395
Abstract
Socially-perceptive images are an important indicator of professionalism, and their analysis allows to estimate level of competence of the expert. The image of the victim can serve as an indicator of professional suitability and be the important factor of psychopreventive maintenance of employees Emercom of Russia. In article there are presented the results of the analysis of structure and the maintenance of an image of the victim in consciousness of operating employees of of State Fire Service of Emercom of Russia and cadets of Saint Petersburg University of State Fire Service of Emercom of Russia. That was done on the basis of research in which 140 examinees, among which 90 cadets of Saint Petersburg University of State Fire Service of Emercom of Russia and 50 employees of State Fire Service of Emercom of Russia who were repeatedly taking part in suppression of fires and rescue of people have taken part. V. L. Sitnikov’s technique “Structure of an image of the person (hierarchical)” was applied to studying of an image of the victim. The basic conclusions: 1) for employees and cadets the most significant are emotional, physical and behavioral characteristics at the description of victims; 2) in an image of the victim in the consciousness of operating employees the negative definitions characterizing delicacy, helplessness of victims prevail, however 75 % of operating employees used not only negative, but also positive statements at the description of the victim; 3) the maintenance of an image of the victim in the consciousness of operating employees and cadets differs in the fact that cadets apply authentically more than negative, emotional characteristics (“panic”, “stress”), and the operating employees use conventional, social characteristics more often (“child”, “woman”) and the characteristics of social intelligence (“trusting”, “understanding”); 4) for the operating employees the victim possesses a larger range of possible qualities and characteristics in comparison with cadets. From aggressive and nervous to quiet and adequate. An images of the victim have a smaller variety of statements at cadets consciousness, and all of them show feelings of pity, compassion; 5) about a half of employees oppose themselves to the victim, 49 % of examinees observed the return projection of an image of the victim. The received results allow to make recommendations about improvement of vocational training of staff of Emercom of Russia. It is necessary to apply more practical tasks, business games, trainings to form more adequate and differentiated image of the victim.

FIRE AUTOMATIC

78-83 547
Abstract
Nowadays the term “ultraearly fire detection” and “early detection of fires” can be encountered in scientific publications, but often authors interpret their essence differently. Sometimes they make no distinction between them, depending on their solution value in comparison with known methods of early fires detection. At the same time the idea of ultraearly fire detection is still not implemented in practice. Therefore, the problem of ultraearly fire detection is considered from scientific, technical, organizational and legal points of view. Scientific aspect. The idea of ultraearly fire detection lies in the fact that it is insufficient to register characteristics of temperature and smoke fields of already developed fires. It entails delayed personnel fire fighting action. It is necessary to monitor changes in these parameters before ignition or, in extreme cases, on very early stage of fire. These changes (signals about ultraearly fire detection) are next: for example, changes of velocity and acceleration of the physical bodies surface heating temperature or volume (including room volume), concentration of specific emitting gases and other characteristic signs. Emitting during heating of many materials carbon monoxide, hydrogen, and carbon dioxide gas molecules change air composition. Registration of such changes allows generate fire alert signal long before smoke and fire appearance. It can be an early warning about unexpected elements heating in protecting object. The technical aspect. Nowadays we have temperature sensors, thermal imagers, automatic various types gas analyzers. In the article, we have considered gas fire detectors which are the most appropriate for ultraearly fire detection today. We substantiate the expediency of terminology change in relation to technical tools, realizing the idea of ultraearly fire detection as well as we detect not fire, but places (points) of possible ignition. Organizational and legal aspect. We have to make an important step on the level of guidance documents to realize the idea of ultraearly fire detection. Terms of early and ultraearly fire detection should be introduced. Only this will stop confusion in terms, allow distinguish researches in separate areas of scientific organizations involved in fire automatic developing.

FIRE-AND-EXPLOSION HAZARD OF SUBSTANCES AND MATERIALS

30-37 468
Abstract
When assessing the level of fire danger of technological process it is necessary to consider the rate of evaporation of the combustible substances and materials, the expiration settings for liquids and gases, concentrated limits of flame propagation for the combustible mixtures in technological devices and equipment. There are presented the Raman spectra of multilayer carbon nanotubes (CNT) used in the experiments. It’s demonstrated reorientation of multiwalled carbon nanotubes external influence variable frequency-modulated potential by atomic force microscopy, that eliminates one of the causes of physical and chemical anisotropy in nanofluids system. The electrical conductivity nanofluids of ethanol-based with multilayer carbon nanotubes increases by 2.5 times by increasing the concentration of CNTs, their functionalization and increasing defects. Presumably the electrical conductivity of nanofluids with low volume fraction of CNTs has a percolation nature, according to which the nanotubes in conjunction with each other to form a base fluid system of conducting channels. In conditions at low content of small orientational ordering additive increases the conductivity. The expiration time of the liquid hydrocarbon with multiwalled nanotubes is increased by 20-35 % with an increase in the CNT concentration. The rate of change of pressure in the saturated ethanol vapor modifications multiwall carbon nanotubes and subjected to the influence of the frequency-modulated potential during the first 15 minutes decreases in average 1.5 times. The rate of weight loss is significantly reduced, which increases fire protection fluid with additives CNT. The mass of evaporated nanofluids with ethanol-based multilayer CNT generally decreased by 30-60 % compared to the base fluid that causes nanofluids stability to thermal degradation index and determines the rheological properties. The mechanism controlling the properties of nanofluids depends on the physical properties of fluid and nanoparticles, as well as the parameters of external influence. The development of nanotechnology methods of controlling the properties of hydrocarbon liquids (creation bottom with adjustable parameters of nanoparticles and chemical free option) will allow you to solve a number of tasks to ensure fire safety in the storage and transportation of flammable liquids and combustible liquids.
38-44 440
Abstract
The aggregate state of combustible substance is the basis for allocation of some classes of the fires and classification of indicators of fire danger. Besides solid, liquid and gaseous substances in fire and technical literature it is accepted to consider disperse systems, in particular dust. Feature of these systems is the fact that actually combustible material in the dust systems are small particles of solid substance, and among indicators of fire danger are available such which aren’t allocated for solid combustible substances and materials, but are applied to gases and liquids. Other fire-dangerous disperse system it is necessary to consider the porous soil structures impregnated with combustible liquids. Such systems are widespread on objects of an oil and gas complex and are a dangerous combustible material on many fires. Indicators of fire danger to these systems aren’t established. Fire-dangerous characteristics of the soil deposits containing oil products are obviously connected with concentration and a type of oil product, and also with soil type. Combustible substance in them are liquid oil products, but it is unacceptable to apply to them indicators of fire danger to liquids. As an indicator of fire danger to the disperse systems containing a combustible liquid phase it is offered to use the concentration of ignition defined experimentally. She is the smallest concentration of oil product in the soil at which ignition and steady burning of system is possible. In work experiments on establishment of concentration of oil products in soils of various type at their limiting saturation are made by oil products. In all studied types of soils ignition of system the soil - oil products perhaps at concentration by 4-8 times smaller, than concentration at which oil product is capable to be emitted in a separate phase and to form liquid congestions on a soil surface. Such conclusion significantly increases potential danger of emergence of the spillage fire at hit of oil products in soil deposits.

FIRE HAZARD OF ELECTROTECHNICAL PRODUCTS

45-51 473
Abstract
After arsons, the main reason for the fires on motor transport is emergency operation of operation of the power supply network (short circuit, overload of electricity cables and big transitional resistance). For Russia it is typical that the cars made 10-20 years ago constantly continue to be operated. The electrical wiring of such cars has a bad condition and often becomes a cause of the fire. Besides, even new cars are equipped with the additional alarm system, powerful musical and video equipment, systems of heating and ventilation, additional headlights. And contacts of the additional equipment often are made in the handicraft way that can lead to big transitional resistance and be a cause of the fire. Studying of nature of emergence and development of big transitional resistance, the techniques of an assessment of probability of emergence of the emergency operation, which connected with the big transitional resistance (BPS), leading to emergence of the fire in the car, will allow to create new recommendations, requirements in the field of fire safety which needs to be considered, to be changed taking into account a tendency of development of the motor transport. The accidents modes in the car power supply networks connected with big transition resistances are the most dangerous, as protection against their emergence does not exist, and development of big transition resistance can lead to sparking, short circuit and other ignition sources. At the same time, the initial reason of emergence of the fire is leveled, in process of the fire and suppression. In article, the stochastic model of the analysis of the emergency modes arising in the power supply network of cars is offered. The Markov model including several absorbing states will allow to calculate to what of the absorbing states the chain will get earlier (or later); in what of them process will stop more often and in what - is more rare. The developed model allows to analyses probability of emergence of the fire from the electric reasons connected with big transitional resistance that allows to make the correct conclusions by production of fire investigations.

FIRE ENGINEERING

84-91 410
Abstract
There are two actual technical tasks for the engines of the fire trucks which are used in the Arctic zone. The first one is the utilization of heat and the second one is the increase of the efficiency of catalytic neutralization of the exhaust pollutants. The device combining catalytic converter (CC) and mineral heat storage system (MHSS) elaborated for fire trucks may help to solve such problems. The device is supposed to be built in the exhaust system of the engine of the fire truck instead of the noise muffler. It allows to storage the thermal energy of the exhaust gas with the use of heat-retaining substance when the engine operates at full capacity, and to deliver the heat back to the catalytic converter when the engine of the fire truck operates at idling mode. The reverse heat delivery allows maintaining the optimum temperature for the effective catalytic neutralization of exhaust pollutants. The process of the excess heat taking, when the engine operates at a forced mode, may contribute to the increase of the operational life and to the decrease of the risk of inflammation of the engine. Physically and mathematically this process may be described with the use of the thermal balance methodical approach. At the same time, the exothermic process of neutralization may be formalized using the classical Arrhenius kinetics approach, which we previously adjusted for the block-designed catalytic converters. The validity of the mathematical model is confirmed with the test of the fire truck AC 4-40 (43202) equipped with the engine KamAZ-740/10 (8CN 12/12). The experiments have shown that the efficiency of the catalyst at idling operation may be increased from 4 to 74 % with respect to the CH neutralization and from 10 to 86 % in respect to the CO neutralization. The results of calculations have confirmed that the use of the elaborated salt heat storage system with the heatexchange surface 1.58 m2 and the length 400 mm, which can be easily built in the exhaust system of the fire truck instead of the noise muffler, allows to solve the problem of the utilization of the excess heat and the increase of efficiency of catalytic neutralization of the exhaust pollutants of the engines of the fire trucks used in the Arctic zone.


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ISSN 0869-7493 (Print)
ISSN 2587-6201 (Online)