The Ontario Building Code | Fire Block Materials
3.1.11.7. Fire Block Materials
(1) Except as permitted by Sentences (2) to (4) and (7) materials used to separate concealed spaces into compartments shall remain in place and prevent the passage of flames for not less than 15 min when subjected to the standard fire exposure in CAN/ulc-S101, "Fire Endurance Tests of building Construction and Materials".
(2) gypsum board not less than 12.7 mm thick and sheet steel not less than 0.38 mm thick need not be tested in conformance with Sentence (1) provided all joints have continuous support.
(3) In a building required to be of noncombustible construction, wood nailing elements described in Article 3.1.5.6. need not be tested in conformance with Sentence (1).
(4) In a building permitted to be of combustible construction, in a combustibleroof system permitted by Sentence 3.1.5.3.(2), and in a raised platform permitted by Sentence 3.1.5.8.(2), materials used to separate concealed spaces into compartments are permitted to be,
(a) solid lumber not less than 38 mm thick,
(b) phenolic bonded plywood, waferboard, or strandboard not less than 12.5 mm thick with joints supported, or
(c) two thicknesses of lumber, each not less than 19 mm thick with joints staggered, where the width or height of the concealed space requires more than one piece of lumber not less than 38 mm thick to block off the space.
(5) Openings through materials referred to in Sentences (1) to (4) shall be protected to maintain the integrity of the construction.
(6) Where materials referred to in Sentences (1) to (4) are penetrated by construction elements or by service equipment, a fire stop shall be used to seal the penetration.
(7) In a building permitted to be of combustible construction, semi-rigid fibre insulation board, produced from glass, rock or slag, is permitted to be used to block the vertical space in a double wythe wall assembly formed at the intersection of the floor assembly and the walls, provided the insulation board,
(a) has a density not less than 45 kg/m3,
(b) is securely fastened to one set of studs,
(c) extends from below the bottom of the top plates in the lower storey to above the top of the bottom plate in the upper storey, and
(d) completely fills the portion of the vertical space between the headers and between the wall plates.
3.1.12. Flame-Spread Rating and Smoke Developed Classification