9.32.3.1.(1)

Intent 1:

To limit the probability that the performance of heating-season mechanical ventilation systems will fall significantly below expectations.

This is to limit the probability of:

• inadequate ventilation, or
• the inadequate control of relative humidity.

This is to limit the probability of the inadequate control of:

• indoor air temperatures,
• airborne pollutants,
• oxygen and other components necessary for breathable air, or
• condensation, which could lead to the generation of pollutants from biological growth or from materials that become unstable on wetting.

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.

Intent 2:

[Clause (a)] To direct Code users to good practice options, such as those contained in CAN/CSA-F326-M, for the design of heating-season mechanical ventilation systems.

Intent 3:

[Clause (b)] To state the application of Subsection 9.32.3., which contains requirements for heating-season mechanical ventilation systems in dwelling units with 5 or fewer bedrooms.