On the Issue of Safe Use of Fiber Cement Materials in the Buildings and Structures

Fiber cement finishing materials are widely used in the construction of industrial buildings and structures due to the complex of valuable operational properties. In the Russian market there are fiber-cement panels with a variety of design solutions for their coloring and application of protective coatings. Fiber cement board is a strong and moisture-resistant composite material made from a cement-sand mixture, reinforcing cellulose fibers and special additives. Not being a non-combustible material, the fiber cement boards in accordance with the current mandatory requirements, as a decorative, finishing and facing material for walls and ceilings have restrictions on their use. Existing domestic requirements regarding the methodology for assessing the combustibility of fiber cement products largely narrow the field of using these materials. Therefore, it is advisable to develop the proposals for amending the test methods and the regulatory framework governing their fire-safe extended scope. In the course of this work execution, the main provisions of the regulatory and methodological framework that establish the requirements for the fire-safe use of fiber cement materials are analyzed. Experimental complex studies of fire hazard properties of various types of samples of the fiber cement finishing panels and slabs were carried out. It is established that fiber-cement materials belong to the class of the least fire-hazardous materials. Advisability is determined concerning the introduction to the national regulatory practice of GOST R «Building materials. Test method for fire hazard under thermal exposure with a single burner (SBI)». Classification parameters of the group of non-combustible materials NG2 were established to amend GOST R 57270—2016 (method 1). Classification parameters of the group of non-combustible materials NG2 for making changes in GOST R 57270—2016 (method 1) are established. Proposals were developed to expand the scope of application of the materials and products made of fiber cement as enclosing structures, partitions, and decorative finishes (cladding) in the buildings and structures.

Combustibility of fuel material for forest species

The work aimed to characterize the flammability of different forest species. The combustible materials were collected in two places with different phytophysiognomies, both in the state of Paraíba, Brazil. The plant materials used were: Poincianella bracteosa, Aspidosperma pyrifolium, Luetzelburgia auriculata, Croton sonderianus and Pinus sp. acicles and branches were used as a control. The burns were carried out in an open area located in the forest nursery, where approximately 0.5 kg of material was weighed on a precision scale. After the organization of the plots, the thickness of each pile was measured with the aid of a ruler graduated in centimeters. To determine the speed of fire propagation, the average time spent by the fire front (m s-1) to travel pre-established distances during the fires was measured. It is observed that among the studied materials, Pinus was the one that presented the lowest weight after burning the material and was the species that presented the highest temperature after burning, followed by C. sonderianus and A. pyrifolium. Before burning, all species showed behaviors, ranging from 30 to 33 °C. It is extremely important to replicate this type of study in forest areas, since the variations found can influence the results. The effect of burning combustible materials on soil temperature was greater in treatments with Pinus and C. sonderianus.

Fire dynamics in the attics

Произведена экспериментальная оценка развития пожаров в объеме чердачных помещений в зависимости от типа кровельного покрытия. По результатам исследования отмечается, что применение кровли из горючих материалов способствует более быстрому образованию сквозных прогаров и выходу пламени за пределы помещения, в то время как в случае использования сплошных настилов из негорючих материалов горение в течение длительного времени развивается в объеме, а после появления общей вспышки быстро распространяется от очага в объеме. Представлены рекомендации по осуществлению мероприятий в области обеспечения требований Федерального закона в части ограничений последствий пожара. The article presents the results of an experimental assessment of fire development dynamics in the volume of attics, depending on the type of roofing. According to the results of the study, it is noted that the use of a roof made of combustible materials contributes to the faster formation of through burnouts and the exit of the flame outside the room, when solid decking made of non-combustible materials is used, fire develops for a long time in the volume, and after the formation of a general flash it quickly spreads from the hearth all over the volume. Open fire time over a roof made of combustible materials is more than twice less than when testing a roof with a solid flooring made of non-combustible materials and makes 5.5 minutes, compared to 13.5 minutes. In a real fire with a large amount of fire load in the volume of the attic the temporary gap may be sufficient to ensure that the fire, in the absence or failure of the fire detection system, covers the entire construction volume before it is detected by random witnesses and information about it is received by the fire department. When using a roof system made of combustible materials, it is noted that despite the high rate of initial fire development, the dynamics of subsequent fire propagation in the roof volume is lower, even in the absence of fire-resistant treatment of wooden structures. Based on the results of the study there are presented recommendations for the implementation of measures to meet the requirements of the Federal Law No. 123-FZ dated 22.07.2008 “Technical Regulations on Fire safety requirements” in terms of limiting the fire consequences.

Simulation of Indoor Fire Dynamics of Residential Buildings with Full-Scale Fire Test

Along with simulated firefighting training, the development of virtual training systems and associated content has recently drawn attention as an alternative method for advanced firefighting training. In particular, to develop virtual training content, it is important to understand the combustion characteristics of indoor combustible materials and appropriately simulate their behavior. In this study, seven types of building fires were selected. From these types, indoor combustible materials of residential buildings were analyzed, and combustion tests were performed for each of three types of combustible materials. Furthermore, three types of indoor spaces, determined according to the combination of indoor combustible materials they contained, were divided into full-scale compartments, and a full-scale fire test was performed using this setup. Finally, the heat release rate and smoke production release of individual combustible materials and the room test were measured over time, and a fire dynamics simulation (FDS) was performed. As a result, it was confirmed that an effective evaluation of the occurrence and spread of fire indoors in buildings is possible through full-scale fire tests and FDS simulations. It is expected that simulation can be used as firefighting training content in the future by applying indoor combustible data and implementing complex and various fire development conditions.

BURNING OF FORESTS IN SNNP «BURABAY» AND WAYS TO MINIMIZE IT

Аридизация климата, наблюдающаяся в последние десятилетия, обусловила увеличение опасности возникновения и развития лесных пожаров. Особенно это проявляется в южных районах, где лесные насаждения произрастают на границе со степью в экстремальных для них лесорастительных условиях. Уменьшение количества осадков, повышение летних температур и усиление ветра приводят к ускоренно- му высыханию напочвенных горючих материалов и, как следствие этого, повышают вероятность прихода в лесные массивы степных пожаров, а также перехода низовых лесных пожаров в верховые. Сосновые насаждения ГНПП «Бурабай» характеризуются повышенной пожарной опасностью. В них велика вероятность перехода низовых пожаров в верховые и создания угрозы населенным пунктам. В целях совершенствования охраны лесов от пожаров проанализированы показатели фактической горимости лесов ГНПП «Бурабай» за период с 2008 по 2019 гг., а также специфика развития указанных пожаров и причины их возникновения. На основе собранных материалов предпринята попытка разработки предложений по совершенствова- нию охраны лесов от пожаров и минимизации послепожарного ущерба. Climate aridization observed in recent decades has led to an increase in the risk of occurrence and development of forest risk. This is especially evident in the southern regions where forest stands grow on the border with the steppe in extreme for them forest growing conditions. A decrease in the amount of precipitation, an increase in summer temperatures and wind increasing leads to an accelerated drying on soil combustible materials and, as a consequence, increases probability of entering into forests steppe fi res as well as transition of ground forest fi res to crown ones. Pine stands in SNNP «Burabay» are characterized by an increased fi re hazard. They have a high probability of transition of ground fi res upper ones and creation of a threat to settlement. In order to improve the protection of forests from fi res the indicators of actual rate of forest burning in SNNP «Burabay» for the period 2009 to 2019, as well as specifi c of these fi res development and the causes of their occurrence were analyzed. On the basis of the collected materials an attempt was made to develop proposals for improving the protection of forests from fi res and minimizing fi re hazardous damage.

Development and application of synthetic NP dispersions to prevent and extinguish forest and peat fires (Review)

Introduction. The analysis of flame retardants and extinguishing agents used for preventing and extinguishing fires in an ecosystem is carried out. It is shown that at present there are no weatherproof, environmentally friendly and cost effective extinguishing agents capable of stopping wood and peat burning. Purpose and objectives. Development of cost effective and environmentally friendly synthetic agents capable of both flame retarding and extinguishing natural combustible materials. Materials and methods. Synthetic dispersions of ammonium phosphates of two- and three-valence metals, as well as wood and peat fireproofed by them are the object of the study. Physical and chemical properties of synthesis products in comparison with their fire retarding efficiency are examined. Fireproofing, fire extinguishing, as well as physical and chemical properties of synthesized products are determined using GOST-regulated methods of thermal and chemical analysis, scanning electron microscopy and original methods. Results and discussion. The formulation of Kompleksil synthetic compound effective in extinguishing and fireproofing wood and peat is optimized using a full factorial experiment. At the same time, the inflow of volatile nitrogen containing products into the gaseous phase is identified as the dominating burning inhibition process common for natural combustible materials. The weather resistance (preservation of fireproof properties in respect of forest combustible materials at 79 mm precipitation), forest and environment enhancement (improvement of mineral nutrition conditions and growth of forest plant communities) properties of Kompleksil compound are identified. Conclusions. A cost effective synthetic compound based on natural mineral materials showing fireproofing and extinguishing efficiency when protecting forest combustible materials and peat is developed. This compound was tested in the process of extinguishing real wildfires; its weather resistance is identified, and the positive response of forest plant communities to the application of this multiple action compound is registered. The use of Kompleksil allows to reduce time expenditures and fire extinguishing agent consumption when extinguishing wildfires, which significantly reduces material damage.

Synthesis and Characterization of New Eco-Friendly Fire-Retardants Based on Soda-Silicate Glass

Fire-retardants (FRs) are additives used to improve the fire-resistance of combustible materials. New generations of FRs must be effective and eco-friendly. Traditional inorganic FRs are non-hazardous but have limited fire-retardancy. Here, we aim to develop an innovative way to enhance the fire-retardancy of inorganic FRs. We synthesized a new type of FRs, called mATH, whose compositions are similar to soda-silicate glass (xNa2O.yK2O.zSiO2.tAl2O3). When applied to unsaturated polyester resin, mATH showed a much better performance than traditional aluminum trihydroxide (ATH). The better performance of mATH originated from its new working mechanism. Dehydrated mATH, as a soda-silicate glass, melts under the heat of the fire, which causes heat sink and produces a molten glass. The molten glass forms a charred insulating layer that prevents oxygen from contacting the interior combustible materials. This phenomenon significantly contributes to the fire-retarding behavior of mATH. Our findings open a new method for developing effective eco-friendly FRs.

Preliminary study for the suitability of eucalyptus chips and coal for combustion in a fluidized bed reactor

The combustion with fluidized bed reactors has as main advantages the best energy utilization of combustible materials and a lower generation of pollutants. The fluidization success depends on the characteristics of the particles that compose the bed. This research aimed to perform a preliminary evaluation and characterization of the energy potential and the fluidization curves in fluidized beds formed by binary mixtures of eucalyptus chips + sand and mineral coal + sand. We tested: 1) physical characterization of solid fuels; 2) chemical characterization of combustible materials; 3) thermogravimetric analysis of fuels; 4) determination of the fluidization curves and minimum fluidization velocity for a polydisperse bed. We observed 19.15 MJ kg-1 of lower calorific value for eucalyptus chips and 10.1 MJ kg-1 for coal. The increase in biomass percentage in mixture caused a pressure drop in bed, indicating the formation of preferred paths and a necessity to increase fluid velocity. The fluidization of coal and Eucalyptus chips can be viable in a bubbling fluid bed process, motivating future theoretical and experimental studies involving the application of this methodology in the development of clean and sustainable technologies.