Fire Resistance Of Steel Structures Research Articles

Early length changes and microscopic phase analysis of phosphorus hemihydrate gypsum fireproof mortar

Abstract Coating the surface of steel structures with phosphohemihydrate gypsum fireproof mortar can improve the fire resistance of steel structures. The hydration curve of phosphorus hemihydrate gypsum (PHG) showed a monotonic increasing trend, and the hydration time was about 1 day. In order to study the hydration process of phosphorus hemihydrate gypsum fireproof mortar, its length change in the early hardening stage was experimentally investigated. The results showed that compared with the hydration time of phosphohemihydrate gypsum, the duration of early length changes in phosphohemihydrate gypsum fireproof mortar was significantly prolonged to about 4 days, and four intervals were clearly observed during this process. Hydroxypropyl methyl cellulose (HPMC) as a water retaining agent, hydroxypropyl starch ether (HPS) as a thixotropic agent, and dispersed latex powder (LP) can all make the four intervals of length changes of fireproof mortar more significant. After adding HPMC, HPS, and LP, it can promote the formation of dihydrate gypsum mainly in fireproof mortar, but dihydrate gypsum crystals were more likely to grow along the [021] direction. The addition of additives can also effectively improve the pore structure of phosphogypsum fireproof mortar.

Fire performance of superabsorbent polymers protected full-scale cold-formed steel wall lined with plasterboards

Superabsorbent polymers (SAPs) have shown promise in enhancing the fire resistance of steel structures because of their exceptional absorbency and water retention capabilities. This study innovatively applies SAP insulation to cold-formed steel (CFS) walls with gypsum (GP) boards to improve fire performance. One full-scale CFS wall underwent axial compression testing at ambient temperature, and four full-scale fire experiments were conducted on CFS walls with load ratios of 0.27 and 0.85. All specimens were sheathed with double layers of GP boards, and rock wool served as the cavity insulation, with SAP insulation material applied to the cavity of wall studs. Additionally, a novel finite element model was developed to simulate the fluid-heat interaction within a furnace-CFS wall. The simulation results showed that SAP insulation material significantly changes the fire-induced failure mode in wall studs at a 0.27 load ratio, transitioning from hot flange (HF) local buckling to local buckling of the whole stud section. The inclusion of SAP insulation material absorbs heat, effectively delaying the rise in wall stud temperature. This property significantly enhances the structural performance of CFS walls during fire exposure. With SAP insulation material, the fire resistance time of the CFS walls increased by over 66 min compared to non-SAP insulation material counterparts. Moreover, increasing the stud web depth and reducing the HF width-to-thickness ratio can enhance the fire performance of CFS walls. The HF critical failure temperature of specimen S2 with an HF width-to-thickness ratio of 80 was 783 °C, 150 °C higher than that of specimen P2 with an HF width-to-thickness ratio of 67. Additionally, the adverse effect of screws on the fire performance of the CFS wall was localized. After 120 min of fire exposure, the temperature on the ambient side, which was severely influenced by the screws, was 360 to 370 °C.

Performance Evaluation of Fireproof Paint and Spray-Type Fireproofing Materials via Heating Experiments

Various strengthening methods are applied to ensure the fire resistance performance of structures. Specifically, steel-framed structures should be fireproofed as they are relatively less fire-resistant than concrete structures. In general, sprayed fireproof materials and fireproof paint are widely applied to improve the fire resistance of steel structures. Fireproof paint improves fire resistance performance by forming an air insulation layer on the surface of members along with volume expansion due to chemical reactions during a fire. This in turn delays the rate of flame temperature transfer to the steel members. In the case of spray-type fireproofing materials, the fire resistance performance of structural members is improved by the insulation performance of the material itself without physical changes. In this study, the fire resistance performance of refractory materials (fireproof paint and spray-type fireproof materials) was experimentally evaluated with respect to exposure temperature, and the differences in insulation performance with respect to each material were confirmed. Additionally, based on the experimental results, the necessity for improving the performance certification system of current fireproof materials was suggested.

Oil and Gas Structures: Forecasting the Fire Resistance of Steel Structures with Fire Protection under Hydrocarbon Fire Conditions

The hydrocarbon temperature–time curve is widely used instead of the standard curve to describe the temperature in the environment of structural surfaces exposed to fire in oil and gas chemical facilities and tunnels. This paper presents calculations of the ratio of time to reach critical temperatures at different nominal fire curves for steel structures such as bulkheads and columns with different types of fireproofing. The thermophysical properties of the fireproofing materials were obtained by solving the inverse heat conduction problem using computer simulation. It was found that the time interval for reaching critical temperatures in structures with different types of fireproofing in a hydrocarbon fire decreased, on average, by a factor of 1.2–1.7 compared to the results of standard fire tests. For example, for decks and bulkheads with mineral wool fireproofing, the K-factor of the ratio of the time for reaching the critical temperature of steel under the standard curve to the hydrocarbon curve was 1.30–1.62; for plaster, it was 1.56; for cement boards, it was 1.34; for non-combustible coatings, it was 1.38–2.0; and, for epoxy paints, it was 1.71. The recommended values of the K-factor for fire resistance up to 180 min (incl.) were 1.7 and, after 180 min, 1.2. The obtained dependencies would allow fireproofing manufacturers to predict the insulation thickness for expensive hydrocarbon fire experiments if the results of fire tests under standard (cellulosic) conditions are known.

A promising strategy for enhancing fire resistance of steel structure: a composite thermoplastic polyurethane sheet adhered to steel plate

It is an effective passive fire protection method for the steel structure by painting fireproof coatings. Here, a feasible strategy for enhancing the fire resistance of steel structures is proposed. Specifically, a kind of adhesive composite sheet based on thermoplastic polyurethane (TPU), ammonium polyphosphate (APP), polyhedral oligomeric octaphenylsilsesquioxane (OPS), titanium dioxide (TiO2) and sodium silicate was constructed and named as Sheet-Ti/Na. The as-prepared Sheet-Ti/Na exhibited excellent flame retardancy and smoke suppression performance. In addition, the Sheet-Ti/Na can firmly adhere to the steel plate through hot pressing and adhesive bonding methods, acting as a non-traditional fireproof “coating”. This feasible coating method can effectively enhance the fireproof and thermal insulation of the steel plates under the action of the hydrocarbon fire at about 1100 ℃. After testing, the char layer of Sheet-Ti/Na can still firmly adhere to the steel plate without any detachment or cracking. Finally, a ceramic-like reaction among TiO2, APP, OPS and sodium silicate to generate pyrophosphates (TiP2O7 and SiP2O7) was clarified. The thermal insulation, flame retardancy and smoke suppression mechanisms of the Sheet-Ti/Na system also were stated. This work offers a promising strategy for rapidly and efficiently preparing fireproof and thermal insulation “coatings” for steel structures.

Temperature-dependent properties of high-strength steel for evaluating the fire resistance of structures

In recent years, high-strength steel (HSS) is finding increasing applications in building construction due to its excellent strength and durability properties. However, structures, incorporating HSS, exhibit lower fire resistance due to rapid deterioration of their mechanical properties at elevated temperatures. For evaluating the fire resistance of steel structures, high-temperature properties of steel are to be specified as input data. The properties of steel not only vary with temperature but also the extent of variation is influenced by the type and grade of steel. This paper presents a state-of-the-art review on temperature-dependent properties of HSS. The available data and relations for thermal, mechanical, and deformation properties of HSS are compiled. Using these data, the variations in the elevated properties of HSS are established and the reasoning for such variation is explained. Finally, the critical properties to be considered for evaluating the fire resistance of structures, incorporating HSS, are discussed.

Особенности расчета предела огнестойкости балок из строительных сталей

One of the main directions of research in the field of increasing the actual limits of fire resistance of steel structures is the development and implementation of fire-resistant rolled products with increased thermal stability. Fire-resistant steels are steels whose yield strength when heated to 600 °C is at least 60 % of the yield strength at 20 °C. For their wide application in construction, information is needed on the change in the strength properties of fire-resistant rolled metal products at high heating temperatures. In addition, it is required to develop a method for assessing the bearing capacity of steel structures considering the nature of the temperature distribution in their cross section. The introduction of fire-resistant steels and the proposed method of calculation will in some cases will allow to ensure the normative limit of fire resistance of load-bearing structures or reduce the cost of their fire protection. The experimental and calculated data are obtained concerning the limits of fire resistance of beams made of steel rolled metal of classes S355, S390, as well as S355P and S390P with increased heat resistance. The use of the method for calculating the fire resistance limit of bent steel structures heated from three sides considering uneven heating in the cross section, demonstrates satisfactory convergence with the experimental data for beams made of building steels, including fire-resistant ones with increased thermal stability. Various levels of static load were modeled under the influence of the temperature regime of a standard fire. The research results contribute to the introduction of new types of fire-resistant building steels for the construction of buildings from metal structures. This will increase their safety and stability in case of fire and will lead to a reduction in the construction costs.

Simulation of nomograms showing the heating of steel structures with flame retardant coatings of different thicknesses (in the water)

Introduction. High temperatures cause deformation of steel structures which also lose stability and the bearing capacity, resulting in the collapse of structures with the subsequent collapse of the building. It is understood that intumescent paints are often used to increase the fire-resistance limits of steel structures up to R 90 and R 120. However the fire protection effectiveness of intumescent paints has not been sufficiently studied for the case of the long-term operation, and the application of this type of fire protection treatment of bearing steel structures requires justification. To ensure the building stability, coupled with the required fire resistance limit of structures, one should study the engineering factors affecting the fire resistance of steel structures that have intumescent paint coatings.Purpose of the research work. Development of approaches to simulation of nomograms demonstrating the heating of steel structures with flame retardant coatings of different thicknesses. The research work solved the following tasks:block diagrams of the research undertaking were developed to find the fundamental relationships between the dynamics of change in the structure of fire protection materials under thermal effects and the fire resistance limit of a building structure based on the choice of the functional criterion;mathematical models demonstrating dependence between the thickness of the dry layer of fire-retardant material were developed; the required fire resistance limit and thermo-physical characteristics of fire-resistant materials based on the experimental studies of the properties and effectiveness of fire-resistant materials were identified;nomograms showing dependences between the thickness of the dry layer of flame retardant materials and the flame retardant efficiency of flame retardants were made.Research methods. Hot Disk TPS 1500 thermal constant analyzer was used to analyze the thermo-physical characteristics of flame retardant materials. Thermal analysis was used to study the properties of flame retardants, as well as physical and chemical transformations occurring inside them under the programmed exposure to temperature effects and with the use of specialized thermal analysis equipment. The study of the fire protection efficiency for steel structures was conducted in accordance with GOST R (Russian State Standard) 53295–2009 “Fire protection means for steel structures. General requirements. The method of fire protection efficiency determination”.Results and their discussion. As a result of the research, an approach to prediction of the fire resistance of building structures was developed in the form of a research flowchart, used to choose the functional criteria. Experimental studies were conducted to identify mathematical dependences between the fire resistance and the indicators, which serve as functional criteria. In particular, when assessing the fire resistance of steel structures, a prediction is made on the basis of thermos-physical indicators. The authors were first to propose the introduction of the function of fire protection materials into the standard pattern of fire resistance analysis in the course of solving static and thermo-physical problems. The obtained data were used to make equations of dependence between the thickness of a dry layer of a fire-retardant material, the required fire-resistance limit of a structure, and the nomogram showing the heating of protected steel structures with fire-retardant coatings of various thicknesses.Conclusions. The results of the studies allowed identifying fundamental relationships between the dynamics of change in the structure of fire-retardant materials under the thermal effect and the fire resistance limit of a building structure on the basis of the choice of a functional criterion. Experimental studies of the properties and effectiveness of fire-resistant materials were conducted to develop a mathematical model showing dependence between the thickness of the dry layer of fire-resistant materials, the required fire-resistance limit and thermal-physical characteristics of fire-resistant materials.

Теплофизические характеристики стали и огнезащитных покрытий при нормированных температурных режимах пожара

PURPOSE. The article is devoted to the experimental study of thermophysical characteristics of steel on an experimental model – a metal plate of 600×600×5 mm, and to determining effective thermophysical characteristics of a fireproof coating made of a two-component epoxy composition under standardized temperature conditions. METHODS. In this work the finite element method implemented in the Ansys Mechanical software complex was applied for numerical thermotechnical calculation. The inverse heat conduction problem method was also applied for determining thermophysical characteristics of fireproof coatings. FINDINGS. As a result of the study the temperature fields were obtained in the cross section of steel structures with a fireproof coating under various fire temperature conditions. The conducted analysis showed that the discrepancies between numerical modeling and experimental data were satisfactory. RESEARCH APPLICATION FIELD. The results obtained can be applied for designing passive fire protection systems for building structures at construction facilities. As a result of the calculations, a number of values of fire resistance limits of structures with a fireproof coating from a two-component epoxy composition were obtained, taking into account the influence of standardized temperature fire regimes. All these data are put down in the tables of structures fire resistance ratings for three critical temperatures values based on which the corresponding nomograms were built. CONCLUSIONS. The study confirms the effectiveness of epoxy-based fireproof coatings to improve fire resistance of steel structures. Thermotechnical calculation and experimental modeling make it possible to determine the effectiveness of fireproof materials and justify their application in buildings and structures designed in accordance with standardized temperature fire modes requirements.

Thermal performance of hybrid fibers reinforced epoxy based intumescent coating for fire resistance of steel structures

ABSTRACT This work is focused on the development of single and hybrid fibers reinforced intumescent fire-resistant coating for steel protection. The methodologies were developed to measure the heat transfer, thermal stability, char expansion rate, chemical bonding and composition of char, residual mass percentage as well as morphology of an intumescent coating. By incorporating 2 wt.% of single basalt fibers in the intumescent coating, the substrate temperature remained stable at 184 oC after 60 minutes of fire test. On the other hand, the hybridization of E glass with the basalt fiber IFRC-BE55-12 in intumescent coating resulted in higher substrate temperature . Field emission scanning electron microscopy (FESEM) confirmed IFRC-B2.5–12 formulation had a compact and dense char . The thermogravimetric analyses results also revealed that thermal stability of the fibers reinforced intumescent formulations was improved and the highest residual mass of 38.7% percentage was obtained for IFRC-B2.5–12.

Post-fire mechanical response of Q960E ultra-high-strength structural steel

The ultra-high-strength steel (UHSS) has gained significant attention in recent years owing to its prominent benefits in structural performance, economics and environmental aspect. The fire resistance of steel structures is always of great concern as the mechanical properties of steel are sensitive to high temperatures which could threaten the safety of the steel structures, and so do UHSS structures. The post-fire mechanical performance of steel is crucial for evaluating the residual capacity of the structure. Therefore, it is also necessary to evaluate the post-fire mechanical properties of UHSS. In this study, tensile tests were carried out to investigate the post-fire mechanical properties of Q960E UHSS with two types of cooling techniques, i.e. cooling in air or cooling in water. The residual elastic modulus, yield stress, tensile strength, tensile strain, rupture stress, and percentage reduction of area of Q960E UHSS subjected to various temperature levels were obtained from the post-fire stress-strain curves. The influence of the cooling techniques and temperature level on the post-fire mechanical properties of Q960E UHSS were discussed, and some empirical predictive equations were proposed for evaluating the post-fire mechanical properties. Finally, a novel stress-strain model was also proposed to predict the post-fire response of Q960E UHSS. The proposed model showed good consistency with laboratory experimental results. Therefore, it is concluded that the model can provide accurate predictions for the plastic strain-true stress curve for various types of steels.

TO THE ISSUE OF THE FLAMMABILITY REDUCING AND THE FIRE RESISTANCE INCREASING OF METAL STRUCTURES

Problem statement. Based on the fire safety concept in the state program of Ukraine, the issue of flammability reducing for materials and fire resistance increasing for structures is selected as one of the priority scientific areas in fundamental and applied research. It provides for the implementation of works aimed at ensuring fire protection, the development of fire protection products that reduce the flammability of materials and increase the fire resistance of building structures, the development and improvement of methods for determining the fire hazard of materials. The purpose of the article. Increasing the fire resistance of metal structures due to the use of fire-resistant intumescent coatings, developing new approaches, criteria and methods for assessing fire resistance and increasing the fire resistance of modern metal structures. Conclusions. As a result of the analytical studies, mathematical models were obtained that allow predicting the fire resistance and increasing the fire resistance for metal structures depending on the thickness of the coating, the given thickness of the metal and the type of fire retardant composition. An engineering methodology for assessing fire resistance and increasing the fire resistance of steel structures was developed.

Effect of bulk density on flame resistance of rockwool in combined fire-resistant facings

Fire protection of steel structures is playing an increasingly important role nowadays. The fire protection of steel structures can be solved with intumescent paint, mortar, fire protection coating and concrete coating. Several fire tests have been performed to check these solutions. Combined structures, which consist of insulation material and fire protection panels, can be used to increase the fire resistance of steel structures. In this article, the application of combined fire protection solutions (combined use of fire protection panels and thermal insulation) was examined. In the experiments, six types of rockwool products with different densities were used as an additional insulation. As a result, the behaviour of combined insulations made with rockwool products of different densities was compared at high temperatures. Based on the laboratory measurements, a finite-element model was also created.

Intumescent Coatings for Fire Resistance of Steel Structures: Current Approaches for Qualification and Design

Intumescent coatings (ICs) are often used for protecting steel buildings during a fire when the structural, aesthetic, and architectural features of the structural members should be preserved. Indeed, ICs form a thin protective layer on the steel surface, that if exposed to fire or elevated temperatures, expands in volume with a consequent reduction in density. Hence, the protective layer captivates heat and protects the structural member from damage or elevated deformation. This reactive fire protection is designed using prescriptive tables, in which the IC thickness is chosen according to the required fire resistance, critical temperature, and section factor of the steel element. These tables are elaborated on the basis of the tests results according to the UNI EN 13381-8 standard, which is the reference for characterizing reactive systems such as ICs. For its reactive nature, this fire protection has to be applied to the structure in a controlled manner, and it is good practice to verify its correct application by measuring thickness and adhesion in situ through regulated methods. The qualification process of IC systems in Italy can be realized through a voluntary certification within the scope of a European technical assessment or by means of a national technical assessment certificate that is mandatory. All these aspects related to qualification, assessment, and design of ICs are often ignored by both designers and manufacturers, especially in Italy. Therefore, this paper describes all the approaches, introducing the main technical differences, in order to provide a sort of guideline on the use of these reactive fire protections.

Numerical and Experimental Analysis of Fire Resistance for Steel Structures of Ships and Offshore Platforms

The requirements for the fire resistance of steel structures of oil and gas facilities for transportation and production of hydrocarbons are considered (structures of tankers and offshore platforms). It is found that the requirements for the values of fire resistance of structures under hydrocarbon rather than standard fire conditions are given only for offshore stationary platforms. Experimental studies on the loss of integrity (E) and thermal insulating capacity (I) of steel bulkheads and deck with mineral wool under standard and hydrocarbon fire regimes are presented. Simulation of structure heating was performed, which showed a good correlation with the experimental results (convective heat transfer coefficients for bulkheads of class H: 50 W/m2·K; for bulkheads of class A: 25 W/m2·K). The consumption of mineral slabs and endothermic mat for the H-0 bulkhead is predicted. It is calculated that under a standard fire regime, mineral wool with a density of 80–100 kg/m2 and a thickness of 40 to 85 mm should be used; under a hydrocarbon fire regime, mineral wool with a density above 100 kg/m2 and a thickness of 60–150 mm is required. It is shown that to protect the structures of decks and bulkheads in a hydrocarbon fire regime, it is necessary to use 30–40% more thermal insulation and apply the highest density of fire-retardant material compared to the standard fire regime. Parameters of thermal conductivity and heat capacity of the applied flame retardant in the temperature range from 0 to 1000 °C were clarified.

Оцінювання вогнестійкості вогнезахищених сталевих балок

Purpose. Development of a computer model for the study of fire resistance of steel structures protected by fire-resistant coatings, using the example of a fire-resistant steel beam created in the LIRA-SAPR software complex (Ukraine). Methods. Finite element method, application of computational methods of numerical modelling of the LIRA-SAPR software complex, mathematical modelling of thermal processes of non-stationary thermal conductivity. Results. A computer model was developed in the LIRA- SAPR software complex, with the help of which thermal engineering calculation of the beam was carried out. The model makes it possible to evaluate the fire resistance of both unprotected and fire-protected steel beams, to take into account the properties of the beam material and the material of the fire-resistant coating. The peculiarity of modelling the non-stationary heating of a fire-resistant steel beam is to specify the thermophysical characteristics of the fire-resistant coating when solving the problem of non-stationary thermal conductivity. The results of the calculated determination of the fire resistance of the fire-resistant steel beam were compared with experimental data. As a result, a satisfactory convergence of the results of the calculation and experimental study of fire resistance was established (the error is no more than 12%). The results of the experimental determination of the fire resistance of unloaded beams under fire conditions of the standard fire temperature regime were analysed. The accuracy of the developed computer model was evaluated with the results of the experiment. Scientific novelty. A finite-element model of a fire-resistant steel beam has been developed in the LIRA- SAPR software complex, which allows calculating the fire resistance limits of beams protected by fire-resistant coatings with scientifically justified parameters with sufficient accuracy for engineering calculations. Practical significance. It consists in creating the basis for the calculated assessment of fire resistance of building structures protected by fire-resistant coatings by creating computer models capable of performing fire resistance calculations. Due to this, there should be a significant reduction in the cost of work on fire resistance assessment and, as a result, an increase in the effectiveness of measures to increase the fire resistance of building structures.

Оценка огнестойкости стальных строительных конструкций с учетом влияния теплообмена с примыкающими смежными конструкциями

Purpose. On the basis of experimental studies and theoretical data, to determine the thermophysical characteristics of an intumescent fire retardant and evaluate the heating of steel structures with intumescent fire protection of the outer surface, taking into account the adjoining of a concrete coating, as well evaluate the effect of heat transfer with a concrete coating on the optimal layer thickness of an intumescent fire retardant to ensure the required fire resistance limit. Methods. Modeling in the system of finite element analysis. Findings. On the basis of a series of experimental and theoretical studies in the ANSYS finite element analysis system, the thermotechnical problem of fire resistance of steel structures with fire protection of the outer surface based on an intumescent composition was solved, taking into account the abutment of a concrete coating. Experimental studies are used to assess the effective values of the thermophysical characteristics of an intumescent composition by solving the inverse problem of thermal conductivity for a computational finite element model using parametric optimization methods. The obtained thermophysical characteristics made it possible to evaluate the heating of steel structures with fire protection, taking into account heat transfer with a concrete coating. Depending on the required fire resistance level and the type of the considered structures (floor slab) and the design situation, taking into account heat exchange with the concrete coating, the optimal thickness of the fire retardant coating that provides the required fire resistance level is reduced by 1.2 ... 4.4 times. Application field of research. The results can be used to solve the fire resistance problems of steel structures with partial and full fire protection of the outer surface during the design and construction of buildings and structures.

Research of Fire Resistance of Elements of Steel Frames of Industrial Buildings

The article considers and analyses the methods by which it is possible to carry out research to determine the fire resistance of elements of steel frames of industrial buildings. It is determined that it is expedient to use the means of computational fluid dynamics, which has no limitations due to the high cost, complexity, environmental friendliness and complexity in comparison with real experiments. In order to conduct the most reliable computational experiments, mathematical models of temperature and mechanical reaction to the thermal effect of fire were created, taking into account the equations of thermal conductivity, systems of differential equations of stress-strain state of solids in their numerical implementation based on the finite element method. The solution of mathematical models was carried out using computational fluid dynamics, which describes the process of heat and mass transfer in test fire furnaces during the determination of fire resistance of steel structures. According to the results of computational experiments it is shown that the limiting state of loss of bearing capacity of vertical and horizontal structures occurs due to the formation of a zone of plastic deformations taking into account the associative theory of plasticity. According to the results of computational experiments, the dependence of the limit of fire resistance on the level of applied load to structures, which is close to linear, was revealed. Based on the obtained dependences and the corresponding graphs, a technique is developed based on the use of maximum deformations of the elements with the corresponding fixation of the limit state on the loss of fire resistance in terms of bearing capacity by bending this curve.

ТЕНДЕНЦІЇ РОЗВИТКУ РЕАКТИВНОГО ВОГНЕЗАХИСТУ (ОГЛЯД ЛІТЕРАТУРИ)

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.

Assessment Methods for Fire Durability of Intumescent Fire Protection Coatings

Fire durability of intumescent coatings is their ability to retain their fire-protective properties under fire conditions (under the influence of real temperature conditions of fire). The peculiarities of application of intumescent fire-protective coatings in single-storey buildings on the steel frame with account of fire load are considered. In this study, the fire hazard assessment of single-storey buildings on a steel frame with the use of sandwich panels as enclosing structures is made. The analysis of fire load values has been made. Numerical experiments on estimation of the indoor fire temperature regime have been carried out. For estimation of influence of temperature modes of fire on fire resistance of steel structures the software complex “Fire Dynamics Simulator” was used, which implements the field mathematical model. Various fire temperature modes (temperature-time dependencies) were obtained. Modelling of fire temperature modes was performed without taking into account active fire protection systems. The most critical and unfavourable by their consequences fire scenarios, used later for solving the heat engineering problem, have been chosen by experts. Numerical experiments on heating of steel structures were carried out by solving the heat engineering problem in conditions of non-stationary heat influence at standard temperature conditions according to ISO 834 and at fire temperature conditions obtained by modelling results. The estimation of equivalent fire duration on loss of bearing capacity for steel structures is made. ANSYS mechanical” computing complex was used for modelling the heating of steel structures, which allows us to perform heat engineering calculation of the structure on the basis of its software model.