scholarly journals Establishing patterns of mass transfer under the action of water on the hydrophobic coating of the fire-retardant element of a tent

2021 ◽  
Vol 4 (10(112)) ◽  
pp. 45-51
Author(s):  
Yuriy Tsapko ◽  
Zinovii Sirko ◽  
Roman Vasylyshyn ◽  
Oleksandr Melnyk ◽  
Аleksii Tsapko ◽  
...  

This paper reports an analysis of the flame retardants for fabrics that has revealed the fact that the meagerness of data to explain and describe the process of fire protection, specifically the neglect of elastic coatings, leads to that the structures made from fabrics are ignited under the influence of a flame. Devising reliable methods to study the fire protection conditions for fabrics results in the design of new types of fireproof materials. Therefore, there is a need to determine the conditions for the formation of a barrier for water mass transport and to establish a mechanism for slowing down water penetration through the material. In this regard, an estimation-experimental method has been constructed for determining mass transfer under the action of water when using a hydrophobic coating, which makes it possible to assess water penetration. Based on the experimental data and theoretical dependences, the intensity of mass flow under the action of water has been determined, which is 0.000177 kg/m2, which ensures fabric resistance. The study results have proven that the process of waterproofing the fabric involves inhibition of the mass transfer process under the action of water by insulating the surface of the fireproof fabric with a hydrophobic coating. It should be noted that the presence of a hydrophobic coating leads to blocking the fabric surface from moisture penetration. Such a mechanism behind the effect of the hydrophobic coating is likely the factor in adjusting the process through which the integrity of an object is preserved. Thus, the sample of fireproof fabric coated with a water repellent demonstrated, after exposure to water, that the amount of water absorbed did not exceed 0.00012 kg, and, for a fabric without a water repellent, was 0.01 kg. Thus, there is reason to assert the possibility of targeted adjustment of the processes related to water penetration of the fabric by using hydrophobic coatings that could form a protective layer on the surface of the material, which inhibits the rate of water penetration.

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

Abstract. The analysis of fire-retardant materials for fabrics is carried out and it is established that the paucity of data for explanation and description of the process of fire protection, neglect of elastic coatings, leads to ignition of fabric structures under the action of flame. The development of reliable methods for studying the conditions of fire protection of fabrics leads to the creation of new types of fire protective materials. Therefore, it becomes necessary to determine the conditions for the formation of a barrier both for high temperatures and for leaching in the presence of precipitation and to establish a mechanism for inhibition of these processes. In this regard, full-scale tests were carried out and it was found out that when the flame is applied to untreated model samples of tent elements made of canvas fabric, the surface ignites and spreads the flame, which leads to their complete combustion within 105...120 s, instead, the model The fire-resistant sample of tent elements did not catch fire when ignited with a gasoline-based substance, and the flame did not spread. In this case, the final combustion was recorded for 3 c and the swelling of the protective coating reached 3...5 mm, and the surface was charred on an area of about 80% from the inside. When tested for fire retardant efficiency for a fire-resistant sample treated with a water repellent (5 % solution of GDJ-94), a decrease in efficiency and carbonization of the material was recorded, which amounted to 100%, and for a fire-resistant sample treated with a water repellent (5 % solution), a decrease in efficiency was recorded due to the combustion of paraffin and local burnout of the material, and carbonization was 100 %. Obviously, such a mechanism of influence of the fire-retardant coating is the factor regulating the process, which preserves the integrity of the object. Thus, there is reason to argue about the possibility of targeted regulation of the processes of fire protection of the fabric by applying coatings capable of forming a protective layer on the surface of the material, which inhibits the rate of heat penetration.


2021 ◽  
Vol 3 (10(111)) ◽  
pp. 34-41
Author(s):  
Yuriy Tsapko ◽  
Аleksii Tsapko ◽  
Olga Bondarenko ◽  
Viktoriia Chudovska

This paper reports the analysis of flame retardants for fabrics that has established that the meagerness of the data that explain and describe the process of fire protection, as well as the neglect of elastic coatings, leads to the combustion of structures made from fabrics under the influence of flame. The development of reliable methods to study the fire protection conditions for fabrics leads to the design of new types of fireproof materials. Therefore, it becomes necessary to define the conditions for the formation of a barrier for burning and flame propagation by a piece of fabric and for establishing a mechanism that would inhibit a temperature transfer to the material. To address this issue, an estimation-experimental method has been devised for determining thermal conductivity when using a fire protection agent as a coating, which makes it possible to assess the thermal conductivity coefficient under the effect of high temperature. Based on the experimental data and theoretical dependences, the coefficient of thermal conductivity for the fire-resistant layer of foam coke was calculated, 0.034 W/(m∙K), which, accordingly, ensures the heat resistance of the fabric. The study results have proven that the process of the thermal insulation of fabric involves the formation of soot-like products at the surface of the sample. The inhibition of the process of heat transfer to the material treated with a composition based on modified phosphorus-ammonium compounds is characterized by the formation of a heat-protective layer of coke at the surface of the fabric. The maximum possible penetration of temperature through the thickness of the coating has been estimated. At the surface of the sample, a temperature was generated that significantly exceeds the ignition temperature of the fabric, and, at the non-heated surface, does not exceed 150 °C. Thus, there is reason to assert the possibility of targeted adjustment of fire protection processes in the fabric by applying coatings that can form a protective layer on the surface of the material, which inhibits the rate of heat transfer


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.


Author(s):  
Lyubov Vakhitova ◽  
◽  
Nadiya Taran ◽  
Konstantin Kalafat ◽  
◽  
...  

Purpose. Identification of the main directions of evolution of scientific researches concerning development and improvement of fire protective reactive coatings of intumescent type for steel constructions. Methods. Analysis of literature sources, study and generalization of information, classification and modeling of chemical processes. Results. As a result of the performed researches it has been shown that of all the developed reactive fire protection systems for increasing the fire resistance of steel structures the intumescent composition of ammonium polyphosphate/ pentaerythritol / melamine / polymer is the most widespread and economically justified. To reduce the cost of fire protection measures, it is necessary to improve the coatings of the intumescent type in the following main areas: increasing of fire protection efficiency with a decrease in the thickness of the fire protection layer; prolongation of life time with strengthening of resistance to external factors; reducing the cost of the prescription composition of intumescent paint due to the use of nanomaterials. Scientific novelty. It has been established that nanoclays, nanooxides of metals and silicon, LDH compounds and their analogues should be considered the most promising and multifunctional. The presence of nanomaterials in intumescent compositions allows to increase the environmental parameters of fire-retardant treatment due to the rejection of halogen flame retardants, boron compounds, formaldehyde resins. In addition, the presence of nanocompounds in intumescent coatings significantly reduces smoke in fire. Practical significance. The conclusions obtained from the literature review are of practical importance for the development of new approaches to the design of fire-fighting materials with improved performance through the use of nanomaterials, which provides a strong fire retardant foam char layer and provides rigidity of the insulation frame.


Author(s):  
Z. Sirko ◽  
◽  
E. Starysh ◽  
N. Tsireny ◽  
O. Tsapcko ◽  
...  

The article presents the results of research on the creation of flame retardant composition for fire protection of cellulose-containing materials. The analysis was performed of flame retardant compositions for impregnation of cellulose-based materials. Phosphorus-based compounds have been shown to be most effective in providing fire protection in the solid phase and during decomposition. They are able to decompose when heated to form phosphoric acid, which inhibits direct oxidation and greatly reduces the spread of fire. Also, noteworthy are compositions based on salts and acids of phosphorus and nitrogen. The mechanism of action of these compositions is aimed at reducing the amount of heat during combustion and becomes insufficient for self-combustion. It was also found that during ignition fire-retardant compositions interact with the components of cellulose, which forms residual phosphorus and nitrogen, resulting in increased efficiency of fire-retardant action. Fire-retardant impregnating compositions are aqueous solutions of flame retardants. The materials are impregnated in a container with a flame retardant solution or sprayed on the surface of the material with an industrial spray. This method is simple and effective, but the result is short-lived. More effective is the method of introducing flame retardant at the molecular level into the fiber structure. One of the important methods is to restore the fire-retardant properties of materials during their operation and products from them.


Fire Safety ◽  
2018 ◽  
pp. 95-100
Author(s):  
M. Semerak ◽  
D. Kharyshyn ◽  
N. Ferents ◽  
T. Berezhanskyi

Currently, in Ukraine and abroad for the construction of high-rise buildings and structures using pipe-like structures. Wide application of pipe concrete columns is due to their high carrying capacity at relatively smaller overall dimensions due to the blocking of cracking in concrete by a steel clasp. The advantages of concrete columns should include more simplified conditions of technology of manufacturing and installation on their basis of bearing structures of floor covering. Piping constructions consist of steel shells and concrete core. Since the steel pipe mainly provides the bearing capacity of the concrete column, its failure or reduction of stiffness, which is characteristic of the fire under the influence of its thermal factors, leads to destruction. Investigation of fire resistance of concrete structures, which are not protected by flame retardant coatings, showed that a steel clasp during a fire after 15 minutes is heated to a critical temperature of 500 ° C.The use of flame retardant coatings is an effective method of fire protection of concrete constructions, which prevents the rapid heating of steel welds and provides a normalized fire resistance limit for such structures. In this work, studies were carried out on the effectiveness of fire protection of concrete columns with different types of fire-retardant materials - mineral wool slabs, special flame retardants and flame-retardant coatings. For fire protection mineral wool materials were used ROCKWOOL plates of the series "Conlit SL150". Mineral wool plates "Conlit SL 150" consist of fibers of rocks of a basalt group, they can withstand, without melting, temperature more than 1000 ° С. The silica-based adhesive "Conlit Glue" can withstand temperatures above 900 ° C, has good adhesion when bonding Conlit SL 150 mineral wool slabs with protective structures. From the second type of fire-retardant materials, the fire-proof composition "Naktresk" was chosen on the basis of gypsum. The coating is formed in the process due to hardening of the mixture on protected surfaces. The third type of flame retardant materials is the flame-retardant intumessent coating "Pyro-Safe Flammoplast SP-A2".It has been established that with the use of fire protection systems on the basis of mineral wool plates "Conlit SL150" and fire retardant "Nutresc", the fire resistance class of reinforced concrete columns increases from R 15 to R 180. The fire protection system on the basis of the painted paint "Pyro-Safe Flammoplast SP-A2" »Increases fire resistance from R 15 to R 75


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


2022 ◽  
pp. 27-36
Author(s):  
LIUBOV VAKHITOVA ◽  
KONSTANTIN KALAFAT ◽  
NADIYA TARAN ◽  
VOLODYMYR BESSARABOV

Purpose. To study the influence of the carbonizing agent structure on the formation of thermal insulating char layer of intumescent system acid donor/polyol and on the fire protection efficiency of the system at high temperatures. Methodology. A fire retardant mixture of an acid donor (phosphates ammonium, urea, melamine)/ polyol was chosen as a model intumescent system. Dispersion of vinyl acetate copolymer with ethylene was used as a polymeric component. The study applied the characteristics of the char layer of the intumescent composition at a certain temperature. The volumetric intumescent coefficient (K, cm3/g), mass of char residue (m, %), structure and density of the char layer are proposed as the main estimated parameters of flame retardant effect. IR spectroscopy was used to identify products of thermolysis of intumescent systems. Determination of fire protection efficiency of intumescent coatings was carried out in a mini-oven under standard fire conditions. Findings. The influence of polyol structure on the formation of thermal insulating char layer of intumescent acid donor/polyol system and the prediction of fire protection efficiency of this system under high temperature conditions has been investigated. It has been shown that under conditions of thermal shock the fire protection efficiency is more dependent on the nucleophilic reactivity of the polyol towards the unsaturated phosphorus atom of the acid donor than on its thermal stability. It has been found that pentaerythritol, dipentaerythritol, starch, dextrin, xylitol and sorbitol are the most effective carbonizing agents, regardless of the structure of the acid donor. It has been proved by infrared spectroscopy that at high temperatures as a result of the decomposition of pentaerythritol one of the reaction products is the aldehydes interacting with pentaerythritol with the formation of oligomeric compounds with a simple ether bond C-O-C. At the same time, pentaerythritol can be considered as a universal source of carbon framework for intumescent flame retardants regardless of the phosphate structure used. Originality. It has been shown that an important factor to increase the fire protection efficiency of intumescent systems is the use of polyols with an increased nucleophilicity in the esterification between polyol and phosphoric acid.Practical value. The optimal polyols as carbonizing agents for formulation of intumescent coatings with enhanced fire protection properties have been determined.


Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3979
Author(s):  
Anna Strąkowska ◽  
Sylwia Członka ◽  
Karolina Miedzińska ◽  
Krzysztof Strzelec

The subject of the research was the production of silsesquioxane modified rigid polyurethane (PUR) foams (POSS-Cl) with chlorine functional groups (chlorobenzyl, chloropropyl, chlorobenzylethyl) characterized by reduced flammability. The foams were prepared in a one-step additive polymerization reaction of isocyanates with polyols, and the POSS modifier was added to the reaction system in an amount of 2 wt.% polyol. The influence of POSS was analyzed by performing a series of tests, such as determination of the kinetics of foam growth, determination of apparent density, and structure analysis. Compressive strength, three-point bending strength, hardness, and shape stability at reduced and elevated temperatures were tested, and the hydrophobicity of the surface was determined. The most important measurement was the determination of the thermal stability (TGA) and the flammability of the modified systems using a cone calorimeter. The obtained results, after comparing with the results for unmodified foam, showed a large influence of POSS modifiers on the functional properties, especially thermal and fire-retardant, of the obtained PUR-POSS-Cl systems.


2021 ◽  
Vol 1038 ◽  
pp. 468-479
Author(s):  
Olga Skorodumova ◽  
Olena Tarakhno ◽  
Olena Chebotaryova ◽  
Oleg Bezuglov ◽  
Fatih Mehmet Emen

Based on the generalization of research results on the processes of obtaining SiO2 sols using tetraethoxysilane and ethyl silicates, the main factors influencing the elasticity of silica coatings on cotton fabrics and their fire-retardant properties are considered. The possibility of forming covalent bonds between the functional groups of cellulose, gel coating and flame retardant layer is considered, which explains the strong fixation of a thin layer of coating on the fibers of the fabric and improve its fire protection. The use of the developed compositions for fire-retardant elastic coatings based on ethyl silicate allows to increase the time of complete burning of cotton from 30s (untreated fabric) to 600s (treated with binary coating).


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