Air leakage tests were conducted in accordance with ASTM E283 "Standard Test Methods for Rate of Air Leakage Through Exterior Windows, Curtain Walls, and Doors." The 2000 mm x 2000 mm (6.6' x 6.6') test specimen assembly was identical to the wall configuration presented in Figures 2 and 3.

Twenty five 65 mm (2.56") BVTS (spaced at 600 mm (24") o.c. vertically and 400 mm (16") o.c. horizontally) were inserted through the 52 mm (2") rigid insulation, vapour barrier and 12 mm (0.5") gypsum sheathing onto the metal studs and fastened to the metal studs with 4.8 mm (0.19") diameter self-tapping screws. The vapour barrier consisted of Perm-A-Barrier (W.R. Grace) and was applied on the exterior face of the gypsum sheathing.

Positive and negative test pressures were placed on the wall specimen. At pressures up to 500 Pa (0.0725 psi) , the air leakage was less than the least detectable value (as dictated by the monitoring system equipment) of 0.02 I/s/m2 (0.025 gal/min/ft2). At pressures up to 1250 Pa (0.18 psi) the air leakage was less than the detectable value of 0.1 I/s/m2 (0.123 gal/min/ft2). The equivalent wind velocity comparable to a 1250 Pa (0.18 psi) pressure is 158 km/h (98 mph). It should be noted that ASTM E283 provides a default test pressure of only 75 Pa (0.01 psi).