scholarly journals Procedure for constructing a mathematical model to determine the time of the initial stage of fire evolution

2021 ◽  
Vol 1 (10 (109)) ◽  
pp. 45-52
Author(s):  
Sergii Zhartovskyi ◽  
Olexander Titenko ◽  
Oksana Kyrychenko ◽  
Ievgen Tyshchenko ◽  
Roman Motrichuk ◽  
...  

To develop appropriate measures and means of fire protection at facilities, it is relevant to form an idea of the phenomenology of the processes of the occurrence, evolution, and termination of combustion. This paper proposes procedures for building mathematical models of the energy component of those physicochemical processes that occur in wood under the influence of fire, which make it possible to determine the time from the beginning of such an impact to the onset of the phase of flame combustion. The adequacy of mathematical modeling was tested experimentally at a standardized installation for studying flame propagation over the surface of wood. The samples used for the reported theoretical and experimental studies were the specimens of unprotected wood made from 20-mm-thick pine sapwood with a density of 400‒550 kg/m3. The samples of fireproof wood (of the same variety, thickness, and density) were impregnated with a fire retardant based on diammonium phosphate and ammonium sulfate (at consumption of 168.2 g/m2 of dry fire-retardant components). The modeling employed the results from the experimental determining of the ignition temperature of unprotected and fire-proof wood, specifically: 235 °C – for unprotected wood, 410 °C – for fire-proof wood, respectively. The results of mathematical modeling and experimental studies confirm the possibility of significant lengthening of time from the onset of fire exposure to the ignition of fire load from wood when nitrogen-phosphorus impregnating agents are used for fire protection. Procedures of mathematical modeling have been proposed to build models for determining the cooling effect from the use of impregnating fire retardants to protect the wood on the prolongation of the stage of a fire start. Mathematical modeling data could be applied when making impregnating fire retardants

2021 ◽  
Vol 2 (10 (110)) ◽  
pp. 51-58
Author(s):  
Yuriy Tsapko ◽  
Roman Vasylyshyn ◽  
Oleksandr Melnyk ◽  
Vasyl Lomaha ◽  
Аleksii Tsapko ◽  
...  

The analysis of fire-protective materials for wooden building structures was carried out and the need to develop reliable methods for studying the process of washing out fire retardants from the surface of the building structure, which is necessary for the creation of new types of fire-protective materials, was established. That is why there arises a need to determine the conditions for the formation of a barrier for washing out and to establish a mechanism for inhibition of moisture transmission to the material. In this regard, a mathematical model was built of washing out fire retardants using a polymeric shell made of organic material as a coating, which makes it possible to estimate the effectiveness of a polymer shell by the amount of the washed-out fire retardant. According to the experimental data and theoretical dependences, the dynamics of the release of fire retardants from the fire-protective layer of the coating was calculated; it did not exceed 1.0 %, and therefore, ensures fire protection of timber. The results of determining the weight loss of the sample under the influence of water indicate the ambiguous impact of the nature of protection on the washout. In particular, this implies the availability of data sufficient for performing a high-quality process of moisture diffusion inhibition and, based on it, detection of the moment, from which a decrease in efficiency of a coating begins. The experimental studies proved that a sample of fire-protected timber after exposure to water for 30 days withstood the influence of a heat flow. In particular, the loss of timber weight after the temperature exposure was less than 6 %, and the temperature of flue gases did not exceed 185 °C. Thus, there is a reason to assert the possibility of directed control of the processes of fire protection of timber through the use of polymer coatings capable of forming a protective layer on the surface of fire-protected material, which inhibits the rate of washing out the fire retardants


2020 ◽  
Vol 11 (3) ◽  
Author(s):  
V. V. Lomaha ◽  
O. Yu. Tsapko ◽  
Yu. V. Tsapko ◽  
O. P. Bondarenko

Reducing the fire prevention of timber is not only an economic task, but also has a social and environmental focus. From economic, technological and environmental perspective, an important problem in ensuring the viability and safe operation of construction sites is the development of fire-retardant coatings for wooden structures. The construction is increasingly looking for new highly effective means of fire protection of wood and wood products which should not only ensure the standardized fire resistance of wood, but also to maintain its operational parameters to solve environmental safety and durability. Studies of the effect of the radiation panel on the ignition of the wood sample have set the parameters of the flame ignition, which makes it possible to influence this process. It is proved that they consist in the formation of a layer of organic material on the surface, which provides heating to a critical temperature, when the intensive decomposition of the material begins with the release of the required amount of combustible gases and their ignition. This makes it possible to determine the effect of fire protection and the properties of protective compositions on the process of slowing down the rate of burning of wood. Experimental studies have confirmed that the untreated sample of wood, under the thermal action of the radiation panel has taken up, the flames spread over the entire surface, which led to its combustion. The application of a fire retardant varnish under the influence of temperature leads to a layer of foam coke and inhibition of heat transfer of high-temperature flame to the material and its ignition. Thanks to this, it became possible to determine the conditions for changing the parameters of combustion and braking during fire protection of wood, by forming a barrier for thermal conductivity. Thus, there is reason to argue for the possibility of directional control of the processes of fire protection of wood by the use of fireproof coatings that can form a protective layer on the surface of the material, which slows down the rate of burning of wood.


Fire Safety ◽  
2021 ◽  
Vol 37 ◽  
pp. 44-51
Author(s):  
E. Hulida ◽  
V. Sharуу

Introduction. Fires in closed premises of production and storage facilities are the most dangerous, because they hold large areas with a significant fire load. The current direction of providing a fire safety system at production and storage facilities in closed premises is to eliminate the conditions of the rapid development of fire and minimizing its effect through the use of fire curtains. This method of fire protection is practically not used in closed premises of production and storage facilities at the present stage. In most cases, fire partitions are used in such situations. Therefore, a topic issue today is the research of limiting the development of fires with the use of fire partitions and minimizing fire effects.Purpose. Investigate the process of spreading the fire in closed premises of production and storage facilities by using fire partitions to limit the speed of fire spread. Problem statement and solution. The following tasks must be solved to provide fire protection of production and storage facilities:1. to investigate the process of fire spread in closed premises of production and storage facilities without the use of fire partitions;2. to investigate the impact of fire partitions use on fire rate.Two possible modes of development fire in the premises are considered to solve the first problem: 1) with the presence of sufficient air (oxygen), with fire occurred in regulated fire load; 2) with insufficient air (oxygen), with fire occurred in regulated ventilation.It is necessary to choose the material and fire partition design accordingly to solve the second problem. The results of experimental studies [11] showed that fire partitions vermiculite-silicate plates can be used for various building structures manufacturing. Closed production and storage facilities structure analysis showed that these premises are constructed in most cases with a grid of columns 9Х12 m.Conclusions and proposals:1) There is only the first mode of fire with sufficient oxygen (air) in closed premises of production and storage facilities with a total area of more than 5000 m2 in the process of fire. The fire that occurred is regulated only by the fire load.2) The use of fire partitions between sections of the premises of production and storage facilities reduces the probability of fire spreading in the premises by about 3 times.3) It is necessary to continue research work in this direction to obtain more significant results of the process of development and spread of fire in the premises of production and storage facilities.


2011 ◽  
Vol 3 (3) ◽  
pp. 91-104 ◽  
Author(s):  
Jerzy Gałaj ◽  
Zbignev Karpovič ◽  
Waldemar Jaskółowski

Fire safety is one of the main requirements with respect to the regulations on the buildings involved into the category of human hazards. Human safety measures are applied equally to inhabitants, users, customers, spectators, etc., as well as to fire brigades taking part in the activities connected with rescue actions. Methods for emission research were applied to estimate thermo-kinetic parameters related to smoke and toxic gases. The methods fall into two types: full scale methods reflect fire conditions and small laboratory scale methods having a significantly lower degree of reflection. This paper presents the results of studies on the influence of BAK-1 and Flamasepas-2 fire retardants produced in Lithuania and applied for timber on the selected parameters of the fire environment. Experimental studies were conducted using a cone calorimeter (small scale) in the closed compartment equipped with measuring devices (full scale). The undertaken studies have demonstrated that considering some parameters, such as heat release rate (HRR), a positive effect of the lower amount of the released heat can be obtained. Unfortunately, in case of the major part of the studied parameters, including time to ignition, CO concentration and extinction parameter reflecting smokiness, worse results (shorter time, higher CO values and higher extinction coefficient) have been observed for the treated timber rather than for the non-impregnated one. The obtained results have showed combustion with piloted ignition. In case of no piloted ignition, the results were slightly different. For all studied specimens treated with fire retardants, no ignition was observed and tests were terminated following 15 minutes. CO concentration and extinction parameter (smokiness) were higher for non-impregnated timber. Full scale experiments have confirmed the above provided information; moreover, it has been found that the application of fire retardant has no significant impact on temperatures in the compartment.


2021 ◽  
Vol 2061 (1) ◽  
pp. 012098
Author(s):  
V Konoplev ◽  
A Zhukov ◽  
Z Melnikov ◽  
V Sarbaev

Abstract The fire load is an integral part of the fire hazard definition. Reducing this load is one of directions to fight fires in transport. To study the physicochemical processes and thermal effects occurring as a result of thermal decomposition of wood fire-proofed by retardants like BAN, OK-GF, OK-DS (OK-GFM), SPAD-0 and their chemical compositions, we used the methods of differential thermal analysis, thermogravimetry, and derivative thermogravimetry. In addition, to study the intensity of physicochemical combustion processes, tests to control changes in woodwork masses and temperature at the top of pipe depending on the duration of combustion of the samples and the consumption of fire retardants were conducted. Fire retardant compositions like OK-GF, OK-DS, Pirilax biopyrene at the consumption of 0.1 kg / m2 ensure flame and combustion resistance of the wood. The analysis of the research results confirmed the possibility of assigning to wood structures of a lorry’s body of the group 1 of flame and combustion resistance. Using the above fire retardants and their compositions in the treatment of lodgment elements and runners significantly affects the possibility and duration of the combustion process of a lorry. This was tested by means of an artificial fire source method (without chemical treatment, the burning time does not exceed 50 minutes). This significantly improves post-collision safety of vehicles with an increased fire load in terms of fire resistance because of using the natural gas as a motor fuel.


Author(s):  
Yu. Tsapko ◽  
◽  
А. Tsapko ◽  
O. Bondarenko ◽  
M. Suhanevich ◽  
...  

The results of experimental studies on the effectiveness of fire protection of easily erected structures made of flammable textile products are presented. An analysis of the directions of use of easily erected structures made of flammable textile products indicates a steady trend towards an increase in their use during the temporary fulfillment of certain tasks of the Armed Forces of Ukraine and units of the. During the heating of such structures, ignition and rapid spread of fire are possible. The operating statistics for easily erected structures have found a low level of safety due to the use of natural fibers (e.g., linen, cotton and blends), which are highly sensitive to heat and fire. Reduction of combustibility and the development of non-combustible and non-combustible materials is one of the main directions for preventing fires and solving the problem of expanding the scope of these materials. Treatment with fire protection means significantly affects the spread of the flame, allows you to reduce the smoke-generating ability and heat release significantly. After the test, it can be seen that the sample of the textile material sustains spontaneous combustion for more than 5 s; sample damage is more than 150 mm. After the test, it is clear that the sample of textile material does not support self-combustion for no more than 5 s; sample damage is no more than 100 mm. The inhibition of the process of ignition and flame propagation for such a sample is associated with the decomposition of fire retardants under the influence of temperature with the absorption of heat and the release of incombustible gases (nitrogen, carbon dioxide), a change in the direction of decomposition towards the formation of incombustible gases and a hardly combustible coke residue. This leads to an increase in the thickness of the coke layer and inhibition of the heat transfer of the high-temperature flame to the material, which indicates the possibility of the transition of textile materials during processing with a fire retardant composition to materials that are non-combustible, which do not spread the flame by the surface.


2018 ◽  
Vol 27 (9) ◽  
pp. 17-25
Author(s):  
N. I. Konstantinova ◽  
T. Yu. Eremina ◽  
E. A. Nikolaeva ◽  
M. M. Almenbaev

Introduction. In order to reduce the fire hazard of textile materials (TM), scientific research is being carried out for the development of various methods of their fire protection. One of the directions in the field of decorative finishing TM with reduced flammability is their surface treatment with fire retardant compositions. Along with the development of fire retardants for TM, it is quite legitimate to study the effects of tissue on human skin, when in contact.Methods. At the stage of development of fire retardant compositions for surface treatment and the choice of the technology of their application, it is necessary to take into account the functional purpose of the TM, the scope of application and operational requirements.Discussion. In developing a fire retardant composition for surface treatment of TM that are in contact with human skin, the authors proposed the use of a number of phosphorus-containing compounds, which are effective fire retardants. However, a significant disadvantage of such compounds is their instability, decomposition and dissociation over time, which leads to irritation of the skin in direct contact with the material. Therefore, research has been carried out and optimal chemical compositions of stabilizers, buffer solutions and their ratios in the fire retardant have been selected. Their use for surface treatment of TM on acellulosic basis makes the TM resistant to ignition and does not adversely affect the skin of a person in direct contact.Conclusions. Based on the experimental data obtained, it follows that one of the possible ways to solve the problem of developing effective fire protection means that meet the requirements of normative documents in the field of fire safety and sanitary hygiene may be modification of compounds based on carbamide compounds with the selection of appropriate stabilizers and buffer solutions.


Author(s):  
A. Kovalov ◽  
◽  
Y. Otrosh ◽  
V. Tomenko ◽  
O. Vasylyev ◽  
...  

Abstract. The results of the development of fire-retardant substances based on domestic materials to increase the fire resistance of fire-retardant steel structures are presented. New compositions of fire-retardant substances on the basis of domestic materials capable of swelling are developed. A series of experimental studies to determine the heating temperature of fire-resistant steel structures. For this purpose, samples of reduced size in the form of a steel plate with a flame retardant applied to the heating surface were used. Fire tests of fire-retardant steel plates coated with the developed fire-retardant substance forming a coating on the protected surface, in the conditions of their tests on the standard temperature of the fire using the installation to determine the fire-retardant ability of fire-retardant coatings. The results of experimental determination of temperature from an unheated surface of steel plates with a fire-retardant covering in the conditions of fire influence at a standard temperature mode of a fire are analyzed. Based on the obtained data (temperature in the furnace and from the unheated surface of steel plates with fire protection system) the solution of the inverse problems of thermal conductivity found thermophysical characteristics of fire protection coating (thermal conductivity and specific volume), which can be used for thermal calculation heating of fire-retardant steel structures at arbitrary fire temperatures. The thermophysical characteristics of the formed fire-retardant coating are substantiated to find the characteristics of the fire-retardant ability of the newly created fire-retardant coating and to ensure the fire resistance of fire-retardant steel structures. The efficiency of the developed fire-retardant coating for protection of steel structures is proved.


2016 ◽  
Vol 861 ◽  
pp. 72-79 ◽  
Author(s):  
Adelaida Fanfarová ◽  
Linda Makovická Osvaldová ◽  
Stanislava Gašpercová

The authors deal with the importance and significance of fire retardants for fire protection in practice. The main aim of this paper is to inform the readers about the possibilities of wood modifications by fire retardants. The authors present the experiment of testing wood specimens applying the experimental scientific method of test for limited flame spread on the test bench under laboratory conditions. The results of the experiment represent fire-technical characteristics that describe the wood behavior during the process of combustion. Different types of fire retardants are evaluated according to the selected evaluation criterion - the weight loss of test specimens. The conclusion summarizes the results of the experiment and recommendations for fire retardant modification in practice.


Author(s):  
T.A. Budykina ◽  
◽  
E.B. Anosova ◽  

The results are presented concerning the experimental studies of the behavior of fire-retardant seals produced by the Ogneza group of companies under thermal exposure up to 1000 °C, obtained by the method of synchronous thermal analysis (thermogravimetry together with the differential scanning calorimetry). Incombustible properties of the M-СORE (NG) seal were confirmed, which showed a decrease in the mass of the material when heated to 1000 °C by 11%, which is due to the mineral composition of the sample (a silica-based material). High thermal stability was shown by the fire-fighting seal M-CORE, the decrease in the mass of the sample of which, after reaching a temperature of 555 °C, stops at 37 %, which indicates the formation of an ash residue. Thermal sealing tape LTU, as a result of the temperature heating starting from a mark of 192 °C, uniformly was losing mass up to a total value of 82 %. The experiment established the sealant swelling. According to the experimental data obtained, the samples M-CORE (NG) confirmed the fire-retardant properties declared by the manufacturer. For the selection of heat-resistant materials that can withstand significant temperature loads during the operation of units and mechanisms, for electrical and thermal insulation, for fire protection of air ducts, equipment, structures, the advantages, and reliability of these seals are obvious. The results of the study (the temperature of the beginning of an intensive decrease in mass, the temperature of the onset of thermal effects accompanying a decrease in mass, the behavior of materials under thermal exposure) can be considered when designing heat and electrical insulation, fire protection of production processes, as well as when determining the level of fire risk of the production facilities.


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