Method for Calculating the Number of Transitions Through Zero Degrees in the Outer Layers of Enclosing Structures

The article presents a new method for determining the required frost resistance of finishing and front facing materials of external walls. In the extension of a theory of thermal stability O. E. Vlasova, M. A. Shklover, B. F. Vasiliev a new method for calculating the temperature on the surface of external wall structures and in their thickness is developed. It considers hourly fluctuations in the temperature of the outside air, hourly changes in the incident direct and scattered solar incident on vertical surfaces of various orientations, as well as the thermal insulation of wall and the heat capacity of the materials of the separate layers. The developed technique made it possible to calculate the temperature on the outer surface of external wall and at the boundary of layers in multilayer walls of various design solutions. The performed calculations made it possible to determine the number of cycles of transitions through the temperature of zero degrees both on the surface and in the thickness of the structure. This method makes it is possible to develop requirements for frost resistance of external finishing and front layers of wall of various designs, oriented to the south, southeast, east, northeast, north, northwest, west and southwest under the influence of hourly changes temperature and hourly changes in diffuse and direct solar radiation incident on vertical surfaces, heat protection qualities of wall materials, their thermal inertia, attenuation of temperature fluctuations of outdoor temperature fluctuations in the thickness of the walls.