The influence of basic components of intumescent paint on fire protection properties is studied. The resulting changes in properties are assessed by the intumescence coefficient and thermal analysis data. Influence of the binder polymer composition on fire protection properties under the same conditions was evaluated, quantitatively using the example of fire-retardant water-dispersion paint; the best result was obtained in the formulation based on vinyl acetate copolymers. The brands of ammonium polyphosphate (PFA) from different manufacturers were investigated under the same conditions. The results of the thermal analysis and testing of the physicochemical properties of the samples on various PFAs are presented, with conclusions about their influence on the fire-retardant properties of the paint. The results of the thermal analysis of the influence of orthophosphoric acid, as a modifying additive, on the fire-retardant properties of the paint are presented.

The experimental evaluation of fire resistance limits for steel constructions with fire-retardant coatings consists of a lot of experiments on the heating of steel structures of buildings by solving a heat engineering problem at various fire conditions. Building design implies the assessment of compliance of actual fire resistance limits for steel constructions with the required limits. Fire resistance limits for steel constructions are determined for “standard” temperature mode, and this can lead to overestimated fire resistance and underestimated heat influence for a real fire. Estimation of the convergence for “standard” temperature mode and possible “real” fire mode, as well as of the compliance of actual fire resistance limits with real fire conditions, was realized in the following stages: mathematical modeling of real fire development by the field model in software package Fire Dynamics Simulation (FDS) with various fire loads and mathematical modeling of steel construction heating for the standard temperature mode obtained by modeling “real” fire modes (the finite difference method of solving the Fourier heat conduction equation at external and internal nonlinearities was used for modeling the process of steel structure heating with the implementation in the ANSYS mechanical software package). Experiments of the assessment of fire-protective paint’s effectiveness were carried out for standard temperature mode and obtained by modeling “real” fire modes. The equivalent fire duration dependence on fire load type was determined. This dependence can be taken into account in determination of fire resistance limits for steel constructions in warehouse building roofing. Fire-protective paint effectiveness was estimated for “standard” temperature mode and various other temperature modes.

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.

Introduction. The fire resistance limits of load-bearing and enclosing structures can be identified using the method of heat-and-mass transfer calculation in case of fire. The multifactorial nature and nonlinearity of the problem makes the application of this method complicated. If necessary, the temperature regime, demonstrating the conditions of real fire, can be applied. In this work, actual fire resistance limits of metal structures of a thermal power station are calculated.Goals and objectives. The co-authors attempt to identify the actual fire resistance limits of bearing metal structures in case of the most dangerous fire development scenario.Methods. Taking into account the complexity of space-planning solutions of a building, the field-focused calculation method was selected. This method is applicable to premises, featuring complex geometric shape, where one geometric dimension is much larger than the others. Non-stationary three-dimensional differential equations of mass, momentum and energy conservation are solved for the gas medium inside a room (the Reynolds type of Navier–Stokes equations), as well as the components of the gas medium and the optical density of smoke. A heat transfer equation is solved to determine the temperature distribution inside the building structure for a one-dimensional case. The fire resistance limit of the building structure is identified as the moment in time following the start of fire, when the temperature in, at least, one point of the structure reaches a critical value.Results and discussion. Calculation results show that in case of the most dangerous fire development scenario, within 15 minutes as of the start of fire, maximum temperatures of load-bearing metal structures are far below the critical temperature of 500 °C.Conclusions. Load-bearing metal structures in an engine room, that has steam turbines, don’t need fire protection.

Проблемы и перспективы в области огнестойкости деревянных конструкций для высотных зданий