( See Note A-9.32.3.8.)
(1)
This Article applies to
(a)
dwelling units that contain a fuel-fired space-heating appliance or fuel-fired water-heating appliance of other than direct-vented or mechanically vented types, and
(b)
ancillary spaces that contain an exhaust device, where the space is not within a dwelling unit in a house with a secondary suite and where the house with a secondary suite contains a fuel-fired space-heating appliance or fuel-fired water-heating appliance of other than direct-vented or mechanically vented types.
(2)
Except as provided in Sentences (6) to (8), any mechanical air exhausting device, other than the principal ventilation fan operating at a rate not greater than the maximum permitted by Table 9.32.3.3., shall be provided with outdoor makeup air supplied by a fan rated to deliver outdoor air to the dwelling unit at a rate
(a)
not less than the exhaust capacity of the device, and
(b)
not greater than that exhaust capacity plus 10%.
(3)
An outdoor makeup air supply fan required by Sentence (2) shall be wired so that it is activated whenever the device for which it supplies outdoor makeup air is activated.
(4)
The outdoor makeup air required by Sentence (2) shall be
(a)
introduced to a normally unoccupied area in the dwelling unit, or
(b)
tempered to at least 12°C before being introduced to occupied areas or to a supply duct system.
(5)
If the outdoor makeup air required by Sentence (2) is not tempered upstream of the supply fan, the supply fan required by Sentence (2) shall be approved by the manufacturer for the handling of untempered outdoor air.
(6)
The provision of makeup air as described in Sentence (2) is not required in a dwelling unit with solid-fuel-burning appliances, where all other fuel-fired appliances are direct-vented or mechanically vented.
(7)
The provision of makeup air as described in Sentence (2) is not required if it can be shown using the test procedures in CAN/CGSB-51.71, “Depressurization Test,” that the maximum depressurization levels to which fuel-fired space- or water-heating appliances and their venting systems will be exposed will not exceed the limits set out in CAN/CGSB-51.71 for the categories of fuel-fired appliances and venting systems installed in the dwelling unit.
(8)
The provision of makeup air as described in Sentence (2) is not required for mechanical exhausting devices operating a subfloor depressurization system installed for the purpose of reducing the risk of radon ingress.