The Ontario Building Code | Construction and Installation of Ducts and Plenums
18.104.22.168. Construction and installation of Ducts and Plenums
(1) Rectangular panels in plenums and ducts more than 300 mm wide shall be shaped to provide sufficient stiffness.
(2) Where the installation of heating supply ducts in walls and floors creates a space between the duct and construction material, the space shall be fire stopped with noncombustible material at each end.
(4) All round duct joints shall be tight-fitting and lapped not less than 25 mm.
(5) Rectangular duct connections shall be made with S and drive cleats.
(6) Trunk supply ducts shall not be nailed directly to wood members.
(8) Ducts in or beneath concrete slabs-on-ground shall be watertight, corrosion-, decay- and mildew-resistant.