The Ontario Building Code | Coverings, Linings and Insulation
6.2.4.8. Coverings, Linings and insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation
(1) Foamed plastic insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation may be used in a ceiling space that acts as a return air plenum, provided the foamed plastic insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation is protected from exposure to the plenum in accordance with Article 3.1.5.12.
(2) Linings of ducts shall be installed so that they will not interfere with the operation of volume or balancing dampers.
In Plain Language
Foamed plastic insulation and other coverings, linings, and insulation used in residential duct systems must meet specific material requirements addressing both thermal performance and fire safety.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.