Combustible Components for Exterior Walls

    (1)  Except as provided in Sentences (2) and (4), combustible components are permitted to be used for an exterior non-loadbearing wall assembly in a building required to be of  noncombustible construction, provided that,

    (a)   the building is,

             (i)   not more than 3 storeys in building height, or

            (ii)   not more than 6 storeys in building height if sprinklered,

    (b)   when tested in accordance with CAN/ULC-S134, “Fire Test of Exterior Wall Assemblies”, the wall assembly satisfies the following criteria for testing and conditions of acceptance:

             (i)   flaming on or in the wall assembly does not spread more than 5 m above the opening, and

            (ii)   the heat flux during the flame exposure on the wall assembly is not more than 35 kW/m2 measured at 3.5 m above the opening, and

    (c)   the interior surfaces of the wall assembly are protected by a thermal barrier conforming to Sentence

    (2)  Except as permitted by Articles and, where the limiting distance in Tables to permits an area of unprotected openings of not more than 10% of the exposing building face, the construction requirements of Table shall be met.

    (3)  A wall assembly permitted by Sentence (1) that includes combustible cladding of fire-retardant treated wood shall be tested for fire exposure after the cladding has been subjected to an accelerated weathering test as specified in ASTM D2898, “Accelerated Weathering of Fire-Retardant-Treated Wood for Fire Testing”.

    (4)  The requirements of this Article do not apply where foamed plastic insulation is used in an exterior wall assembly of a building and the insulation is protected in conformance with Sentences and (2).

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