Intent 1:
To limit the probability of openings in the joints
of flexible sheet material (such as polyethylene) under in-service
tensile stresses, which could lead to a loss of airtightness.
This is to limit the probability of:
- 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.