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.

In experiment planning research, mathematical methods play an active role. The main task of the researcher is to choose the optimal methodology for conducting the experiment. The experiment is an abbreviated design of full factorial tests and can be considered acceptable due to the small correlation between influencing factors and outputs. The features of the formulations of new composite fire retardant materials have been investigated. The main physical and chemical properties of the materials have been determined to provide fire protection.

Исследование огнестойкости стальных конструкций покрытия складского здания в условиях различного температурного воздействия

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.

Исследование влияния температурного режима пожара на эффективность вспучивающегося огнезащитного покрытия, предназначенного для огнезащиты стальных конструкций

The results are given of numerical experiments on heating of steel structures of buildings roofing by solving a heat engineering problem in conditions of non-stationary heat influence at standard temperature mode according to GOST 30247.0 and at fire temperature mode. The estimation of equivalent duration of fire for steel roofing structures is made. For modeling of heating of steel structures the computational system allowing to carry out thermal engineering calculation of a structure on the basis of its program model was used. For estimation of fire temperature modes the software package “Fire Dynamics Simulator” (FDS) was used, which implements the field mathematical model.