DIRECTIONAL VAPOR BARRIER DEPENDENT TO OPERATE UNDER CONDITIONS OF VARIABLE MOISTURE Russian patent published in 2018 - IPC B32B27/08 E04B1/66 

FIELD: construction; manufacturing technology.

SUBSTANCE: invention relates to the field of buildings insulation and concerns a directional vapor barrier to operate under conditions of variable humidity. Invention also relates to the use of a vapor barrier for the buildings insulation, to a system comprising such a vapor barrier, and to the use of a certain film for insulation a closed by an outer skin space in buildings. Vapor barrier comprises at least two layers, wherein one layer depends on moisture, and the other layer does not depend on moisture. For the first layer, the ratio for the resistance S_d at an average relative humidity of 25 % to S_d at an average relative humidity of 71.5 % is more than 3. For the second layer, the ratio for the resistance S_d at an average relative humidity of 25 % to S_d at an average relative humidity of 71.5 % is less than 1.5.

EFFECT: due to a certain layers combination, the vapor barrier is sensitive to the direction permeability for water vapor, so it can be used for purposeful drying of roof structures in house building, as well as, the moisture dependence of the vapor barrier provides faster drying of the roof structure and / or the insulating surface at a high moisture content in the insulation.

33 cl, 27 dwg, 4 tbl, 2 ex