| Abstract [eng] |
When the thermal properties of thermal insulation products made of rigid polyisocyanurate foam (PIR) are determined during their operation, when these products are installed in building envelopes under different ambient temperature conditions, their thermal properties may change, changing the heat consumption of the whole building. Changes in the thermal conductivity of PIR and the impact of these changes on the heat loss of buildings are studied in three groups: changes in the thermal conductivity of the material with changing mean product temperature, changes in the product after a certain period of high or low temperature, and changes related to PIR facings; changes in heat transfer through structures insulated with PIR (when installing PIR in partitions, joining and cutting of products is inevitable, therefore linear thermal bridges may form in the corner joints of buildings due to different thermal conductivity of materials and facings); possible errors in the prediction of heat loss through partitions of a building related to the determination of the declared thermal conductivity of PIR (selection of geometrical parameters of the sample to avoid lateral heat loss), assessment of the effect of facings and aging technique. The results of previous studies did not provide sufficient evidence of positive or negative changes in the determination and evaluation of thermal conductivity of PIR products and their impact on heat loss in buildings. As the use of PIR in energy-efficient buildings increases, a thorough assessment and justification of changes in the thermal properties of this material will contribute to a more accurate assessment of the energy consumption of buildings and the optimal use of building thermal insulation materials. |
