To limit the probability that the performance of polyethylene sheets will fall significantly below expectations, which could lead to an inability to resist loads induced by air pressure differences, which could lead to the sheets rupturing or tearing at fasteners, or becoming prematurely brittle, which could lead to the failure of the membrane.

This is to limit the probability of a loss of airtightness, which could lead to:

• excessive heat loss or gain due to air mass transfer,
• excessive air infiltration and exfiltration,
• excessive airborne vapour transfer from interior above ground and exterior below ground, or
• precipitation ingress due to air pressure differences.

This is to limit the probability of:

• an inadequate control of the temperature of interior spaces, drafts, indoor relative humidity, or water accumulation,
• pollutant ingress from the exterior, including combustion products from parking garages, or particulates,
• the generation of pollutants from biological growth or from materials that become unstable on wetting, or
• deterioration, which could lead to compromised integrity of assemblies acting as or protected by environmental separators.

This is to limit the probability of:

• negative effects on the air quality of indoor spaces,
• the inadequate thermal comfort of persons, and
• contact with moisture.

This is to limit the probability of harm to persons.

To limit the probability that the performance of polyethylene sheets will fall significantly below expectations, which could lead to an inability to resist loads induced by air pressure differences, which could lead to the sheets rupturing or tearing at fasteners, or becoming prematurely brittle, which could lead to the failure of the membrane.

This is to limit the probability of a loss of airtightness, which could lead to:

• excessive heat loss or gain due to air mass transfer,
• excessive air infiltration and exfiltration,
• excessive airborne vapour transfer from interior above ground and exterior below ground, or
• precipitation ingress due to air pressure differences.

This is to limit the probability of condensation or the accumulation of water, which could lead to deterioration, which could lead to compromised structural integrity of assemblies acting as or protected by environmental separators, which could lead to harm to persons.

To limit the probability that the performance of polyethylene sheets will fall significantly below expectations, which could lead to an inability to resist loads induced by air pressure differences, which could lead to the sheets rupturing or tearing at fasteners, or becoming prematurely brittle, which could lead to the failure of the membrane.

Where the air barrier system separates a garage, or suite containing a garage, from residential space, this is to limit the probability of a loss of airtightness, which could lead to gas and fumes migrating from the garage into the remainder of the building, which could lead to the accumulation of gas and fumes and their subsequent ignition by a nearby ignition source, which could lead to a fire or explosion, which could lead to harm to persons.

To limit the probability that the performance of polyethylene sheets will fall significantly below expectations, which could lead to an inability to resist loads induced by air pressure differences, which could lead to the sheets rupturing or tearing at fasteners, or becoming prematurely brittle, which could lead to the failure of the membrane.

Where the air barrier system separates a garage, or suite containing a garage, from residential space, this is to limit the probability of a loss of airtightness, which could lead to the leakage of carbon monoxide gas into living space, which could lead to the asphyxiation or acute poisoning of persons.