• Air barrier systems must be able to provide an effective barrier to air infiltration and exfiltration under pressure differences caused by:
  • Stack Effect
  • Mechanical System Effects
  • Wind Effects

• If polyethylene sheeting is used as the air barrier system it must meet the minimum standards for that material as listed in the ABC

9.25.3.2. (1) Air barrier systems shall possess the characteristics necessary to provide an effective barrier to air infiltration and exfiltration under differential air pressure due to stack effect, mechanical systems or wind.

(2) Where polyethylene sheet is used to provide airtightness in the air barrier system, it shall conform to CAN/CGSB-51.34-M, "Vapour Barrier, Polyethylene Sheet for Use in Building Construction."