The Ontario Building Code | Air Barrier System Properties Air Barrier System Properties

(1) Except as provided in Sentence (2), materials intended to provide the principal resistance to air leakage shall,

(a) have an air leakage characteristic not greater than 0.02 L/(s·m²) measured at an air pressure difference of 75 Pa, or

(b) conform to CAN/ulc-S741, "Air Barrier Materials – Specification".

(2) The air leakage limit specified in Sentence (1) is permitted to be increased where it can be shown that the higher rate of leakage will not adversely affect any of,

(a) the health or safety of building users,

(b) the intended use of the building, or

(c) the operation of building services.

(3) The air barrier system shall be continuous,

(a) across construction, control and expansion joints,

(b) across junctions between differentbuilding assemblies, and

(c) around penetrations through the building assembly.

(4) The structural design of air barrier systems installed in assemblies subject to air pressure loads shall comply with Article and Subsection 5.2.2.

Section 5.5. Vapour Diffusion

5.5.1. Vapour Barriers