NEWS, CONFERENCES, EXHIBITIONS
SAFETY OF SUBSTANCES AND MATERIALS
Introduction. Publications reflecting the peculiarities of creating structures made of polymer composite materials (PCM) on determining the required fire-safety level are studied. It was noted that insufficient attention to ensuring the required level of fire resistance of PCM structures, which prevents their use in various fields and, in particular, in engineering is paid.
Analytical part. The analysis of publications on research flame retardant efficiency of intumescent flameretardant coatings (FRC) indicators as one of the polymer types and fire protection means of structures made of PCM is carried out. The necessity of solving the urgent task of ensuring the required adhesion between the FRC and PCM, as well as ensuring durability and durability of coatings during the operation period is noted. The results, indicating the possibility of a significant improvement in the PCM fire risk indicators at a relatively low coating thickness are presented.
The analysis of publications showed the important role and possibilities of heat engineering calculations for modeling temperature fields in structures and determining the required thicknesses of intumescent FRC and other fire protection equipment. This role is partly associated with the fact of impossibility of testing such PCM structures as well. It is shown that there is a technique that is currently being successfully used to calculate the heating of polymer composite structures and can be considered as a basis for further improvement. As can be seen from the presented simulation results, bearing composite structures have to be designed in an optimal shape, which, in combination with fire-retardant coatings, will ensure their fire resistance.
Conclusion. The results, demonstrating possible ways to ensure the required fire safety indicators of the PCM structures are presented. On this important and promising topic, tasks that need to be carried out are also noted.
Introduction. In most cases, the attackers use combustion initiators — affordable and cheap oil products (gasoline, diesel fuel, engine oils, or their mixtures) to intensify combustion. In order to establish the cause of a criminal fire, it is necessary to determine the presence of a fire initiator at the fire site. The study has been conducted in order to establish the interfering effect of decomposition products of the carrier object on the determination of the presence of diesel fuel.
Materials and methods. Polyurethane (car upholstery), which is able to adsorb liquid on its surface, was chosen as the carrier object, and diesel fuel was used as the combustion initiator, as the most common combustion initiator. The method of fluorescence spectroscopy was used in the study process. Study results and discussion. Polyurethane samples with diesel fuel on its surface and without it were burned in a muffle furnace at temperatures from 200 to 300 °C for 5–20 min. After firing, the crushed samples were extracted, and fluorescence spectra were measured with the help of fluorimeter.
Conclusion. Analysis of the study results showed that when heating polyurethane samples covered with diesel fuel, it is possible to identify the combustion initiator as a strongly burned diesel fuel up to 250 °C C inclusive for 5, 10, 15, and 20 min. When polyurethane samples are heated to temperatures above 250 °C, the identification of the combustion initiator as highly burnt diesel fuel is impossible.
MATHEMATICAL MODELING, NUMERICAL METHODS AND PROGRAM COMPLEXES
Introduction. In the branch structure of management of Russia an important place is occupied by geographically distributed objects (branches) of large industrial enterprises of the fuel and energy complex. The considered enterprises, in accordance with the criteria approved by the legislation, belong to the category of hazardous production facilities. An important task is to determine the cause of the danger.
Methods of research. To detect hazards in any automated control systems used methods by which information is collected on the parametric values of the functioning of production facilities. To conduct research on the detection of hazards, a number of approaches are used: based to determine the parameters (invariants) of the models of controlled objects; to solve the problems of modeling (forecasting); to use analytical redundancy. There is a modelfree method of hazard detection in automated control systems, which is based on the representation of only the data of control signals and measurements of the parameters of the functioning of dynamic objects. It is based on the algebraic condition of solvability of the problem of identification of a mathematical model of dynamic object functioning.
Problem statement. It’s required on the basis of the measurement results the input signals coming into the automated control system, to develop a parametric value for the critical zone of occurrence of hazards with the aim of displaying information on the display of the workstation operator.
Problem solution. It is offered to represent models of object, in serviceable and faulty States, in the form of matrices that will allow solving problems of identification of the closed objects for any input signals, irrespective of availability of information on parameters of control system. The speed and accuracy of detection of the fact and time of danger (system failure) are determined by the sampling frequency of the signals and coincide with the time interval between the two consecutive measurements.
Conclusion. The advantage of the proposed approach is its independence from the parameters of the controlled object model. The use of the proposed approach for detection makes it possible to transfer the security management system of the enterprise to a new qualitative level due to constant traceability of the process of functioning of production facilities, increasing the speed and reliability of detection of the fact and time of danger.
LIFE SAFETY
Introduction. Employees’ safety in buildings demands systematic monitoring of both the robustness and stability of buildings, which provide its mechanical safety and fire safety. The most important event in the personnel’s firesafety monitoring system in building and facilities of all functional fire hazard classes are the systematic (not less than once per six months) practical training of the people, which perform their work on hazard location. As a rule, the following is applied: printed information, lections, audio recordings, slides, posters, code grams, video films, TV shows, group discussions, situation modeling, game management. However not a single of those training types gives the possibility for assessing the actual level of knowledge of skills achieved by personnel, all the more so in combination with the prevention measures of automated fire safety systems functioning.
Analytical part. In this article we review the case of “involuntary experiment” — small-scale fire in a medical facility, which provided the possibility to assess the achieved level of fire-safety management and offered the range of the measures for its prospective improvement. The number of the problems was solved to achieve the goals, namely: personnel survey of laboratory building, in which the fire outbreak happened; the brief analysis of fire safety system of the medical facility was conducted; the conclusions were made about the safety culture level in the medical facility; the recommendations were given for enhancing the facility’s fire safety system.
Conclusion. The analysis of the facility’s operation unit condition showed the personnel’s readiness for action during emergency. However, the late detection of fire and low efficiency of the fire detection systems made the specialists think that it is necessary to use innovative technology in fire alarm systems to reduce the evacuation start time.
Introduction. The number of multi-storey buildings and structures increases every year. Now there is an improving tendency of elderly people who remains be able to work even in old age. The issue of evacuation people with reduced mobility is especially acute. In high-rise buildings, evacuation paths are very long, which makes the evacuation process for these groups not only difficult and dangerous, but also physically impossible. At the same time, most problems with using elevators as the main evacuation path have been almost solved.
The article’s purpose is to simulate the evacuation process from a high-rise building with using elevators as one of the main path. Tasks: 1) determine the evacuation time dependence on the movement parameters of people different mobility groups; 2) compare the evacuation time on the staircase and through the elevators.
Methods. The Pathfinder PC was used to calculate the people evacuation from a modeled building. The evacuation time was calculated using both ladders exclusively and with partial use of vertical elevator units. The calculations were carried out taking into account the presence of the reduced mobility population group.
Results and discussion. The evacuation time was obtained using only the ladder and compared with the theoretical computation. The effect on evacuation time with time parameters (the evacuation start and signal delay), the flow composition (various mobility groups), and the evacuation base level for each group are calculated. The evacuation time is compared on the staircase and through elevators. Optimal percentage dependences of people, who use the first and second versions of evacuation, are obtained.
Conclusion. The requirements for fire elevators safety are as high as for non-smoke-free staircases. In 60-storey office buildings (in contrast to the 20-storey), the use of elevators and manage measures for the human flow significantly reduce the evacuation time. For high-rise buildings in the future, it is necessary to consider the organization of evacuation with the use of elevators.
STATISTICS AND SYSTEM ANALYSIS
Introduction. Most Post-Soviet countries share a method of regulation called RRR (Risk Regulation Reflex) (Blanc 2012). Scheduled inspections are one of the distinct features of this approach in Russia. GPN (Gosudarstvennyy Pozharnyy Nadzor — State Fire Regulation) especially favors this type of inspections. This agency accounts for one-third of all scheduled inspections in the country (N = 915 966). It cites fire prevention and the preservation of life as the primary objectives of these activities.
Aims and purposes. Our goal is to check if scheduled inspections actually achieve these objectives. Thus we test this normative statement empirically.
Methods. In order to do so, we use Poisson count regressions for panel-data and population-averaged panel-data models by using General Estimating Equations. In order to perform this test, we turn to numerous administrative data sources: regional data on the number of fires and its specifics, life loss, number of inspections and data on inspected businesses.
Results and discussion. Our analysis demonstrates that there is no tangible proof of scheduled inspections helping to avoid fires or victims during them. These results have serious implications as inspections are costly and time-consuming both for business and governmental agencies. This result somewhat contrasts with an existing scholarship. Randomized inspections by OSHA are proved to increase safety levels without damaging businesses' financial results (Levine, et al. 2012).
Conclusion. We argue that this seeming contradiction occurs due to general ineffectiveness of current scheduled inspections procedure.
QUESTION – ANSWER
The main requirements of regulatory documents on the design and installation of cable products with the conductors of aluminum alloy 8000 series are considered. Data on safe variants of contact connections of conductors between themselves and with contacts of electrical accessories are summarized. The permissible methods of laying electrical wiring of aluminum alloys of grades 8030 and 8176 in residential and public buildings are presented. Primary scopes and allowable current loads of the considered cables and wires are indicated. References to regulatory documents of foreign countries that determine the procedure for the use of wiring from aluminum alloys are given.
QUESTION - ANSWER
Consider the enabling factors that contribute to an effective fire fighting, and adverse factors that hinder effective fire fighting. The distribution of the flow rate of each irrigator and the total flow rate of AFES of different distribution networks with sequential activation of all irrigators located on each of the protected dictating areas, with the total flow rate of AFES not more than 10 l/s and at the initial intensity of the dictating sprinkler inorm > icalc = 0.06 l/(sec · m2) and inorm = 0.08 l/(sec · m2). It is shown that if the diameters of the distribution network pipelines are chosen correctly, then even with the normative value of the intensity of irrigation of the dictating sprinkler, the total flow rate of the AFES with the activation of four irrigators, calculated according to the method given in Set of rules 5.13130.2009, may be less than the normative value by about 1.5 times due to which the protected dictating area is expanded compared to the normative Snorm = 60 m2.
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