Intent 1:
To limit the probability that the performance of
membrane-type vapour barriers, other than polyethylene, will fall
significantly below expectations with respect to:
- pliability,
- tensile strength,
- elongation under load, and
- water vapour permeance.
This is to limit the probability of
uncontrolled water vapour diffusion into insulated assemblies, which
could lead to:
- condensation, or
- compromised thermal performance of components intended
to provide resistance to heat transfer.
This is to limit the probability of:
- an inadequate control of the temperature of interior
spaces or relative humidity,
- 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 environmental separators.
This is to limit the probability of:
- negative effects on the air quality of indoor spaces,
and
- the inadequate thermal comfort of persons.
This is to limit the probability of harm to persons.