(1)  Ventilation ducts shall conform to the requirements of Part 6 for supply ducts, except that exhaust ducts that serve only a bathroom or water closet room may be of combustible material provided the duct is reasonably airtight and constructed of a material impervious to water.

    (2)  Exhaust ducts shall not discharge into heated or unheated enclosed spaces.

    (3)  Where an exhaust duct passes through or is adjacent to unheated space, the duct shall be insulated to not less than RSI 0.5.

    (4)  Where a duct carrying outdoor air that is not tempered or not mixed with indoor air passes through heated space, it shall be insulated to not less than RSI 0.5 except that, where such a duct is exposed in the heated space for more than 3 m of length in the heated space, it shall be,

    (a)   insulated to not less than the values listed in Table, and

    (b)   provided with a vapour barrier.

(5)  A kitchen exhaust duct not equipped with a filter at the inlet end shall be designed and installed so that the entire duct can be cleaned.

    (6)  Ductwork for cooking appliance exhaust fans shall,

    (a)   be of noncombustible, corrosion-resistant material, and

    (b)   lead directly to the outdoors without connection to other exhaust fans or ducts.

    (7)  Ductwork for cooking appliance exhaust fans shall be equipped with a grease filter at the intake.

    (8)  All ductwork shall be permanently supported or clipped to prevent sagging, excessive movement and vibration.

    (9)  All ducting connected to supply and exhaust fans shall be constructed so as to inhibit air leakage at joints.

    (10)  Where rectangular duct is used in place of round duct, it shall be selected according to Table

Article Ontario Regulation 332/12 Building Code,   Information published by oncodes.ca for educational purposes only.