9.25.5.1

1) Sheet and panel-type materials incorporated into assemblies described in article 9.25.1.1 shall conform to article 9.25.5.2., where

a) The material has

i) an air leakage characteristic less than 0.1 L/(s · m2) at 75 Pa, and

ii) a water vapour permeance less than 60 ng/ (Pa · s · m2) when measured in accordance with ASTM E 96/E 96M, "Water Vapour Transmission of Materials", using the desiccant method (dry cup), and

b) the intended use of the interior space where the materials are installed will not result in high moisture generation.

2) Where the intended use of the interior space will result in high moisture generation, the assembly shall be designed according to Part 5.