New Results on Research on Changes in Thermal Conductivity Over Time of Boards Made of Polyisocyanurate Foam (PIR) of Modern Production

The article is devoted to the description of complex studies of changes in the thermal conductivity of boards made of polyisocyanurate foam (PIR) of modern production, lined on both sides with foil. A comparison of two methods for determining the steady–state thermal conductivity is carried out – it is shown that the NIISF method is preferable to the method set out in GOST R 56590–2016. According to the results of a series of experiments on the most modern test equipment in the Russian Federation, the law of the change in thermal conductivity over time of the tested PIR brand and the values of the steady-state thermal conductivity at an average temperature in the sample of 10оC and 25оC was found. When using the most accurate device for determining thermal conductivity, almost absolute convergence of the experimental results with the results of mathematical modeling using the NIISF method was obtained. The differences in the values of the steady-state thermal conductivity, which are obtained during tests on different devices, are explained. The conversion coefficient between the values of thermal conductivity PIR at an average temperature of 25оC and 10оC is found. The obtained new results and methodological developments are of great practical importance in connection with the widespread use of PIR boards in modern construction.

P.P. PASTUSHKOV^1,2, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
V.G. GAGARIN^1,2,3, Doctor of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
D.A. IL’IN^3,4, Candidate of Sciences (Engineering) (This email address is being protected from spambots. You need JavaScript enabled to view it.);
I.F. NAGAEV⁴, Head of Technical Support Division SM and PIR (CTO) (This email address is being protected from spambots. You need JavaScript enabled to view it.)

¹ Research Institute of Building Physics Russian Academy Architecture and Construction sciences (21, Lokomotivniy Driveway, Moscow, 127238, Russian Federation)
² Institute of Mechanics Lomonosov Moscow State University (1, Michurinsky Avenue, Moscow, 119192, Russian Federation)
³ Moscow State University of Civil Engineering (National Research University (26, Yaroslavskoye Highway, Moscow, 129337, Russian Federation)
⁴ LLC “TechnoNICOL-Construction Systems” (room 13/ I, floor 5, 47/5 Gilyarovskogo Street, Moscow, 129110, Russian Federation)

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