Patent ID: 8728605

Claim:
A water vapor permeable multi-layer thermal insulation including two water vapor permeable outer layers encapsulating inner air and water vapor permeable layers of insulation material and at least one inner separating layer of an air-open fibrous material interleaved with the inner insulation layers and having a mean flow pore size that allows water vapor to move from one side of the at least one inner fibrous separating layer to the other and through the inner insulation layers yet restricts mass movement of air from one side to the other of the at least one inner fibrous separating layer to form a barrier to convection, the multi-layer thermal insulation having a moisture vapor transmission rate (MTVR) of at least 1,200 g/m 2 ·day and a thermal resistance (R) of at least 1.40 m 2 ·K/W.