Intent 1:
To limit the probability of inadequate airflow through
the vented space, which could lead to:
- condensation in the space, or
- the formation of ice dams, which could lead to the ingress
of water.
This is to limit the probability of:
- compromised thermal performance of components intended
to provide resistance to heat transfer, which could lead to an inadequate
control of the temperature of interior spaces,
- water accumulation in interior spaces or an inadequate
control of 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 ceilings acting as 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.
Intent 2:
To exempt junctions of sloped roofs and exterior
walls where preformed baffles are installed from the minimum clear
air space dimensions specified in Sentence 9.19.1.3.(1), based
on the demonstrated effectiveness of a reduced unobstructed space
provided by insulation baffles.