To limit moisture condensation.

To limit the probability of an uncontrolled diffusion of
water vapour from air in heated space into insulated wall, ceiling and floor
assemblies.

This is to limit the probability of:

- 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, or
- the inadequate thermal comfort of persons.

This is to limit the probability of harm to persons.

To limit moisture condensation.

To limit the probability of an uncontrolled diffusion of
water vapour from air in heated space into insulated wall, ceiling and floor
assemblies.

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