RESEARCH OF THE INFLUENCE OF EXTERNAL VERTICAL ENVIRONMENTAL STRUCTURES ON THE SPREAD OF FIRE ON THE SURFACE OF WALLS

Abstract

Purpose. Using FDS modelling to investigate the influence of external vertical enclosing structures on the spread of fire on the surface of external wall structures with facade insulation with combustible insulation.Methods. Using the software package Pyrosim performed тumerical modelling of the dynamics of development and spread of fire on the surface of the thermal insulation and finishing system, which serves as a user shell for the program Fire Dynamics Simulator (FDS). To visualize the results of calculations, the software module of the PyroSim Smoke view system was used, which allows building appropriate graphical representations of temperature distributions. This system also allows you to monitor the dynamics of temperature fields and reproduce the heating process with animation.Results. With the help of computer modelling of fire test parameters of facade insulation system for fire propagation in FDS environment, numerical and graphical indicators were obtained by computer simulation of the fire test parameters of the facade insulation system for fire propagation in the FDS environment. They characterize the process of occurrence, spread and development of fire by the surface of the facade insulation system. Also, we established the influence of external vertical enclosing designs on a fire surface of outside walls with a warming of a facade by a combustible heater. The obtained results of numerical modelling of the parameters of the fire test of the facade insulation system for the propagation of fire in the FDS environment indicate that the overall standard deviation in the theoretical data was higher than the results of experimental stud-ies. Thus, the presence in the structure of a fragment of the building vertical wall (inner corners of the building) creates a “shielding effect”, i.e. the flame emanating from the window is reflected and the temperature on the surface of external walls with facade insulation rises significantly. Thus, for thermocouples T15-T17 the temperature rises by 140-220 °C; for thermo-couples T19-T21 – by 180-350 °C; for thermocouples T27-T29 – by 110-190 °C, respectively.In addition, the presence of external vertical enclosing structures on the facade of the building contributes to the increase in temperature and inside the structures of external walls with facade insulation, as evidenced by the readings of thermocouples T33 and T35 – an increase of 50-100 °C; thermocouples T36 and T38 – increase by 50-180 °C.Practical value. The results of numerical simulations obtained by the author are aimed at the use of design organizations in the installation of fire belts using noncombustible mineral wool boards in the inner corners of the building as insulation in the presence of window and balcony openings to prevent fire from spreading on facade systems in residential buildings.