6.2.3.2.(2)ATTRIBUTION:
Functional Statement:
F20
To support and withstand expected loads and forces.
F80
To resist deterioration resulting from expected service conditions.
Objective:
OH1.1, OH1.2
APPLICATION:
Moisture and corrosion resistance of air ducts installed
in locations where they may be subjected to excessive moisture, for heating,
ventilating and air-conditioning systems, in buildings to which Part 6 applies [see Sentence
1.3.3.2.(1) of Division A for application
of Part 6].
This also applies to buildings to which Part 9 applies [see Sentence
1.3.3.3.(1) of Division A for application
of Part 9], with respect to ducts for:
- mechanical ventilation systems other than self-contained systems serving single dwelling units, as stated in Sentence 9.32.1.2.(2),
- the ventilation of storage garages for more than 4 motor vehicles in residential occupancies, as stated in Sentence 9.32.1.1.(3),
- the ventilation of all occupancies other than residential occupancies, as stated in Sentence 9.32.1.1.(2),
- heating systems, including combustion air ducts and ducts for air-conditioning systems other than those serving individual dwelling units, as stated in Sentence 9.33.1.1.(2), and
- air distribution systems serving heating systems in which the rated heat input exceeds 120 kW, as stated in Sentence 9.33.6.1.(2).
INTENT:
To limit the probability that an inadequate resistance to
moisture or corrosion will lead to condensation in ducts due to contact with
wet soil or other sources of moisture, which could lead to the deterioration
and collapse of ducts, which could lead to a reduction in airflow, which could
lead to:
- the inadequate control of:
- relative humidity or indoor air temperatures,
- surface temperatures, or
- air velocity, or
- an inability to maintain adequate indoor air temperatures, which could lead to the condensation of moisture from interior spaces on interior surfaces or within assemblies, which could lead to compromised integrity of environmental separators or of elements protected by such 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.