Thermogravimetric analysis of the pyrolysis and combustion kinetics of surface dead combustibles in the Daxing’an Mountains

In boreal regions, the frequency of forest fires is increasing. In this study, thermogravimetric analysis was used to analyze the pyrolysis kinetics of dead surface combustibles in different forest types within the Daxing’an Mountains, China. The results show that the combustible material load of forest types, the Larix forest (LG) is relatively high. Base on the E of kinetic parameters, the LG, and Quercus forest (QM) forest types had relatively high combustibility values and comprehensive combustibility values for 1-, 10-, and 100-h time lags. According to the obtained P values, the pyrolysis of dead surface fuels with 1-, 10-, and 100-h time lags is relatively difficult in the Larix / Betula mixed forest (L-B) and QM forest types. Therefore, mixed forests of the LG, L-B, and QM tree species can be established as fire-resistant forests to establish a fire barrier, reduce the combustibility of forest stands, and reduce the possibility of forest fires.

Fire Resistant Watertight Structural Doors

With the impact of increased fire resistance requirements that NAVSEA is invoking on ship programs, and the lack of structural doors (i.e., watertight) that are also fire resistant, the industry can benefit from having a compliant option for structural doors that maintains the required internal shipboard fire zone boundaries using only one structural door. Currently using either legacy Navy standard watertight single doors or the new standardized family of watertight single doors tested for pressure and shock qualification during the prior NSRP project, would require installation of two doors in close proximity to one another at fire zone boundaries. One that serves as a fire barrier and the other serving to maintain watertight integrity, or some other mitigating design. A fire resistant watertight door design will reduce the area and volume penalty to ship designs compared to alternate methods and will reduce the ship cost due to having fewer doors to purchase and install. Upon incorporation in a revised Navy standard drawing, these drawings are expected to be invoked on current and future shipbuilding contracts, which will provide a strong basis for widespread implementation after the project is completed.

METHODS OF EXPERIMENTAL RESEARCH JUSTIFICATION OF MINIMUM GEOMETRIC PARAMETERS OF GRAVEL BACKFILL IN THE OIL RECEIVER OF THE TRANSFORMER SUBSTATION

Transformer is one of the most fire-hazardous types of equipment at power substations. In case of emergency operation or damage to the integrity of the case they can cause a fire. Statistics on fires show that 50 % of fires in the energy sector are transformer equipment; as a rule, such fires are accompanied by an emergency spill of oil from the transformer and its ignition. Existing approaches to limiting the spread of fire during accidents at oil-filled transformer substations are insufficient and economically costly to minimize the consequences of burning transformer oil spills. At the same time, a number of design parameters have been identified that negatively affect the effectiveness of fire control. In particular, the Rules for Arrangement of Electrical Installations provide for the provision of electrical substations with oil receivers which is covered with gravel, and the latter is constantly polluted due to environmental influences which impairs its capacity and cooling capacity. The design and geometrical parameters of oil receivers with oil removal by oil drains defined in Rules for Arrangement of Electrical Installations can be a subject of scientific researches for their improvement. The purpose of this article is to determine the main provisions of the methodology of experimental studies to substantiate the minimum geometric parameters of gravel backfill in the oil receiver of the transformer substation. The ultimate goal of the study is to identify patterns of changes in the temperature of transformer oil from the parameters and characteristics of the oil pan, which should perform the function of a fire barrier and cooling the oil below the flash point. The essence of the method of experimental research is to identify patterns of reduction of the combustion temperature of transformer oil to a temperature below the flash point depending on the geometric parameters of the gravel backfill during oil draining into the emergency tank (oil tank). The developed technique allows to determine changes in the temperature of transformer oil from the geometric parameters of the oil pan, which should perform the function of a fire barrier and cooling the oil below the flash point.

MODERN TRENDS IN THE DESIGN OF CONCERT HALLS

Changes in the engineering technologies of concert halls and the choice of finishing materials are discussed in this article. The latest developments and technologies help to enhance the acoustic properties and create a creative, contemporary interior. The acoustics of the hall need to be regulated by the degree of diffuse reflection. Finishing materials are one of the main aspects of the formation of the interior space of a concert hall. In order to ensure optimal sound conditions, special attention should be paid to the decoration of the ceiling space and sidewalls of the room. Various types of mid-to-high frequency, low frequency and wide frequency absorbers are used for this purpose. This paper deals with the physical, mechanical and aesthetic characteristics of sound-absorbing materials and trademark designs that are presented in the Ukrainian market. The quality of sound and light equipment and its correct placement will ensure the maximum service life of the concert hall. Depending on the three-dimensional planning solution, as well as the technical and economic characteristics of the room, you can choose the scheme of air distribution: "bottom-up", "top-down" or multi-zone scheme. It is determined that it is advisable to use infrared heaters to heat the auditoriums. When choosing the furniture of concert halls, it is necessary to take into account the general style of the building and the color scheme of the selected finishing materials. For concert halls, it is advisable to select seats made using modern technologies: triplexing, fire barrier, options, mobility systems, sound absorption and more. The main artistic and aesthetic means of shaping the environment of the concert halls are soft and hard decorations, as well as small stuff. The use of innovative technologies and the use of modern finishing materials increases the attendance rate of these objects and provides comfort to the viewers. Keywords: concert hall, decoration materials, interior design, acoustics.

Огнестойкость железобетонной конструкции с деформационным швом при знакопеременных нагрузках

Правильное проектирование, устройство и монтаж деформационных швов дают возможность обеспечить длительный срок службы основных несущих и ограждающих конструкций зданий, а также элементов внутренней и внешней отделки. Огнестойкие заполнения устанавливают для компенсации возможных изменений ширины шва от первоначальной ширины в горизонтальные и вертикальные деформационные швы монолитных и сборных железобетонных конструкций зданий и сооружений различного назначения, а также в зазоры между торцом вертикальных стен и межэтажных перекрытий. Для защиты деформационных швов в конструкциях зданий и сооружений от воздействия пожара применяются огнестойкие заделки. В европейских нормативных документах такие противопожарные барьеры специально разрабатываются для применения в деформационных швах и работают при сжатии, растяжении и сдвиге шва. В России изделия и материалы, выполняющие функцию противопожарного барьера, не испытываются в условиях знакопеременной нагрузки. В статье приведена методика испытаний на огнестойкость для деформационного шва в железобетонной конструкции. Получены результаты по параметрам целостности и теплоизолирующей способности для железобетонных плит с последующим в сторону увеличения ширины зазора между плитами и сдвига их относительно друг друга на +25 % составляет не менее 245 мин.Buildings and structures of complex architectural forms and large extent are subject to deformations under the influence of fluctuations in the temperature of the outside air, uneven sedimentation of the soil base, seismic phenomena and other causes. To prevent cracks in bearing and fencing structures, expansion joints are provided that cut the building into compartments. Proper design, construction and execution of expansion joints are of great importance in construction, as they provide the opportunity to provide long service life and fire resistance of the main load-bearing and enclosing structures of buildings, internal and external finishes. Normative requirements for the device and technical parameters of fire protection of expansion joints do not currently exist, and since the expansion joints are elements of load-bearing and enclosing structures, their fire resistance is determined in conjunction with the rest of the elements of fire protection barriers, use and application is regulated by the norms of Russian federal legislation. To increase the overall fire resistance of the construction, special fire barriers are used, which are installed inside the expansion joints. The article presents an overview of the fire barriers of expansion joints of both foreign and domestic producers. It is shown that for the protection of expansion joints in a fire, fire barriers are used, specially designed for use in expansion joints, which are guaranteed to work with compression, stretching and shear. It has been established that the production of innovative fire-retardant materials is one of the main tasks of fire safety. This is also the way of the consistent transformation of the idea into a product that passes through the stages of research, design development, production and realization in civil and industrial buildings. It is necessary to choose a comprehensive solution that ensures the maximum satisfaction of the requirements when performing fire protection work to protect the expansion joint when exposed to a fire. The authors declare that the structures (products) intended for fire protection of the expansion joint should provide a stable own mechanical tensile strength of at least 40%; at least 50% compression; for a shift of not less than 20%, the retention of elastic properties at the manufacturer’s declared maximum tensile-compressive stress per product of not less than 100 cycles. After the test, the structure (article) should not have mechanical damages and deformation of the filler, as well as the manufacturer’s declared fire resistance tested with at least 20% expansion from the design width of the expansion joint. When using other fillers for the fire barrier, it is recommended that the above requirements should be met using material that provides deformation characteristics, both in the compression of the joint and during its stretching, and in the shear, during the entire period of the intended use. Particular attention should be paid to the technology of interfacing the structures (products) of fire barriers when they are installed in expansion joints along the entire length, which is guaranteed to prevent the appearance of technological gaps and voids.

Fire barrier based on expanded perlite composites

Decreased strength of building materials as a result of flame impingement (e.g. during a fire) is one of major threats in the construction branch. For these reasons, the effectiveness of fire safety systems in various kinds of facilities or structures is extremely important. One of the determinants of this effectiveness is so-called fire insulation, i.e. time expressed in minutes after which an increase in the temperature of a protected structure or facility exceeds a certain admissible value (140 °C). The results of investigations presented in the article concern the determination of the effect of various mineral binders used in the manufacture of insulation boards from expanded perlite on fire resistance and, in consequence, on extending the time of fire insulation in the conditions of cellulose and hydrocarbon fire. The conducted research has revealed that the fire resistance of perlite products can be modelled by selecting adequate mineral binders, with respect to specific applications and economic considerations. Insulation boards based on expanded perlite – depending on the binder used – were characterized by a fire insulation ranging (with a board thickness of 50 mm) from 50 to 100 minutes in the conditions of cellulose fire and from 20 to 30 minutes in the conditions of hydrocarbon fire.

Intumescent Polymer Metal Laminates for Fire Protection

Intumescent paints are applied on materials to protect them against fire, but the development of novel chemistries has reached some limits. Recently, the concept of “Polymer Metal Laminates,” consisting of alternating thin aluminum foils and thin epoxy resin layers has been proven efficient against fire, due to the delamination between layers during burning. In this paper, both concepts were considered to design “Intumescent Polymer Metal Laminates” (IPML), i.e., successive thin layers of aluminum foils and intumescent coatings. Three different intumescent coatings were selected to prepare ten-plies IPML glued onto steel substrates. The IPMLs were characterized using optical microscopy, and their efficiency towards fire was evaluated using a burn-through test. Thermal profiles obtained were compared to those obtained for a monolayer of intumescent paint. For two of three coatings, the use of IPML revealed a clear improvement at the beginning of the test, with the slopes of the curves being dramatically decreased. Characterizations (expansion measurements, microscopic analyses, in situ temperature, and thermal measurements) were carried out on the different samples. It is suggested that the polymer metal laminates (PML) design, delays the carbonization of the residue. This work highlighted that design is as important as the chemistry of the formulation, to obtain an effective fire barrier.