Combustion Air Masonry Fireplaces
(1) Every solid fuel-fired fireplace, including a factory-built fireplace, shall have a supply of combustion air from outdoors in accordance with Sentences (2) to (7).
(2) The combustion air shall be supplied by a noncombustible and corrosion-resistant supply duct.
(3) The supply duct shall have,
(a) a diameter of not less than 100 mm or equivalent area, and
(b) an exterior intake for entry of air from the outdoors.
(4) The supply duct shall contain a tight-fitting damper that shall be located close to the interior outlet and be operable from the room containing the fireplace.
(5) The operating mechanism shall clearly indicate the actual position of the damper.
(6) The interior outlet shall,
(a) be located as close as possible to the opening in the face of the fireplace, and
(b) be designed to prevent embers from entering the supply duct.
(7) Where a supply of combustion air is provided directly to the fire chamber of a fireplace, including a factory-built fireplace or a steel fireplace liner, the installation shall comply with the “Outdoor Air Supply” requirements provided in CAN/CSA-A405-M, “Design and Construction of Masonry Chimneys and Fireplaces”.
Article 9.22.1.4 Ontario Regulation 332/12 Building Code, Information published by oncodes.ca for educational purposes only.