Intent 1:
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.