Thermal engineering tests of external enclosing structures of residential buildings of mass construction in conditions of major repairs
Currently, the issue of modernizing the housing stock of mass construction, formed in the fifties of the twentieth century, is becoming more and more relevant. The main part of such houses are five-story panel buildings with cold attics, flat or gable roofs, worn-out engineering systems, and poor-quality thermal protection of enclosing structures. Often such houses were built in a record 12 working days, rapidly solving the problem of unsettled post-war life of millions of families. At the same time, the quality of enclosing structures and buildings in General was at a low level. Currently, the annual cost of heating, ventilation and hot water supply for panel houses requiring major repairs or demolition is 150-250 kWh/m<sup>2</sup>. Taking into account losses in external heat supply systems, this indicator increases to 1200-1500 kWh/m<sup>2</sup>. In this paper, the authors consider the study of heat engineering parameters of mass-built panel houses, concerning the achievement of the required parameters of thermal protection, thermal conductivity, humidity and temperature of certain nodes. Thus, the authors found that the enclosing structures reach the required level of thermal protection only in the second year of operation, and also identified some thermal defects of panel houses. The article analyzes a method for determining the durability of finishing layers, based on the variable effect of positive and negative temperatures on the sample of the enclosing structure. The researchers determined the maximum levels of durability for samples of foam silicate with different types of plaster (foam silicate with dense and porous plaster - 80 and 90 cycles, respectively, foam silicate with a lining of dense and porous ceramics - 150 cycles). The authors present a method of non-destructive testing for determining the thermophysical parameters of the fence, based on measuring the difference in temperature values, heat flow and their subsequent processing. In General, the method allowed to automate the thermophysical experiment, the discrepancy between the calculated and reference values exceeds 10 %, while the method is characterized by speed and energy efficiency.