The Ontario Building Code | Protection of Foamed Plastics
184.108.40.206. Protection of Foamed Plastics
(1) Except as provided in Sentence (2), foamed plastics that form part of a wall or ceiling assembly in combustible construction shall be protected from adjacent space in the building, other than adjacent concealed spaces within attic or roof spaces, crawl spaces and wall assemblies, by,
(a) one of the finishes described in Subsections 9.29.4. to 9.29.9.,
(b) sheet metal mechanically fastened to the supporting assembly independent of the insulationhttp://thehandyforce.com/insulation/" title ="Toronto home insulation">insulation and having a thickness of not less than 0.38 mm and a melting point not below 650°C provided the building does not contain a Group C major occupancy, or
(c) any thermal barrier that meets the requirements of Clause 220.127.116.11.(2)(e).
(2) Foamed plastic insulation having a flame-spread rating of not more than 500 is permitted to be used in factory-assembled doors in storage garages serving buildingsof residential occupancy provided that,
(a) the insulation is covered on the interior with a metallic foil,
(b) the assembly has a surface flame-spread rating of not more than 200, and
(c) the assembly incorporates no air spaces.