3.2.3.8 — Protection of Exterior Building Face

(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 3.1.5.12. (5). (2) Except as permitted by Articles 3.2.3.10. and 3.2.3.11., where the limiting distance in Tables 3.2.3.1.B. to 3.2.3.1.E. permits an area of unprotected openings of not more than 10% of the exposing building face, the construction requirements of Table 3.2.3.7. 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 3.2.3.8. (1) and (2).

(1) Except as provided by Sentences (3) to (5) and Articles 3.2.3.10. and 3.2.3.11, the fire-resistance rating, construction and cladding for exposing building faces of buildings or fire compartments shall comply with Table 3.2.3.7. (2) Reserved (3) Except as provided by Sentences (4) and (5) and Articles 3.1.4.8. and 3.1.6.9., cladding for buildings or fire compartments where the maximum permitted area of unprotected openings is more than 10% of the exposing building face need not be noncombustible where the wall assembly complies with the requirements of Sentence 3.1.5.5. (1) when tested in conformance with CAN/ULC-S134, “Fire Test of Exterior Wall Assemblies”. (4) Except as provided by Articles 3.1.4.8. and 3.1.6.9., cladding for buildings or fire compartments where the maximum permitted area of unprotected openings is more than 10% but not more than 25% of the exposing building face need not be noncombustible where the wall assembly complies with Article 3.1.5.5. (5) Except as provided by Articles 3.1.4.8. and 3.1.6.9., cladding for buildings or fire compartments where the maximum permitted area of unprotected openings is more than 25% but not more than 50% of the exposing building face need not be noncombustible where, (a) the limiting distance is greater than 5 m, (b) the building or fire compartment and all combustible attic or roof spaces are sprinklered, (c) the cladding, (i) conforms to Subsection 9.27.6., 9.27.7., 9.27.8., 9.27.9. or 9.27.10., (ii) is installed without furring members, or on furring not more than 25 mm thick, over gypsum sheathing at least 12.7 mm thick or over masonry, and (iii) after conditioning in conformance with ASTM D2898, “Accelerated Weathering of Fire-Retardant-Treated Wood for Fire Testing”, has a flame-spread rating not greater than 25 on the exterior face when tested in accordance with Sentence 3.1.12.1. (1), (d) the cladding, (i) conforms to Subsection 9.27.12., (ii) is installed with or without furring members over gypsum sheathing at least 12.7 mm thick or over masonry, (iii) has a flame-spread rating not greater than 25 when tested in accordance with Sentence 3.1.12.1. (2), and (iv) does not exceed 2 mm in thickness exclusive of fasteners, joints and local reinforcements, or (e) the wall assembly complies with Article 3.1.5.5. (6)[[NO_FORMULA]] Revoked: O. Reg. 89/23, s. 9 (5). (7)[[NO_FORMULA]] Revoked: O. Reg. 89/23, s. 9 (5). (8) The construction requirements for the exposing building face that are listed in Table 3.2.3.7. shall be satisfied before the area of unprotected openings may be increased as permitted by Sentence 3.2.3.12. (1).