3.1.11.5 — Fire Blocks in Horizontal Concealed Spaces

(1) A crawl space that is not considered as a basement by Article 3.2.2.9. and in which sprinklers are not installed, shall be separated by construction conforming to Article 3.1.11.7. into compartments not more than 600 m2 in area with no dimension more than 30 m.

(1) Except as permitted by Sentences (2) to (4) and (7) fire blocks 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). (3.1) In a building or part of a building permitted to be of encapsulated mass timber construction, wood nailing elements referred to in Article 3.1.6.11. need not be tested in conformance with Sentence (1). (4) In a building permitted to be of combustible construction, in a combustible roof system permitted by Sentences 3.1.5.3. (2) and 3.1.6.7. (1), and in a raised platform permitted by Sentence 3.1.5.8. (2) or 3.1.6.12. (1), fire blocks are permitted to be, (a) solid lumber or a structural composite lumber product conforming to ASTM D5456, “Evaluation of Structural Composite Lumber Products”, not less than 38 mm thick, (b) phenolic bonded plywood, OSB or waferboard not less than 12.5 mm thick with joints supported, or (c) two thicknesses of lumber or a structural composite lumber product conforming to ASTM D5456, “Evaluation of Structural Composite Lumber Products”, 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 or structural composite lumber product not less than 38 mm thick to block off the space. (5) Openings through fire blocks shall be protected to maintain the integrity of the construction. (6) Where fire blocks 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.

(1) A building classified as Group C is permitted to conform to Sentence (2), provided, (a) it is sprinklered, (b) it is not more than 12 storeys in building height, (c) it has a height of not more than 42 m measured between the floor of the first storey and the uppermost floor level that does not serve as a rooftop enclosure for elevator machinery, a stairway or a service room used for no purpose other than for service to the building, and (d) it has a building area not more than 6 000 m2. (2) Except as provided in Article 3.2.2.16., the building referred to in Sentence (1) is permitted to be of encapsulated mass timber construction or noncombustible construction, used singly or in combination, and, (a) except as provided in Sentence (3), floor assemblies shall be fire separations with a fire-resistance rating not less than 2 h, (b) mezzanines shall have a fire-resistance rating not less than 1 h, and (c) loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly. (3) In a building that contains dwelling units that have more than 1 storey, subject to the requirements of Sentence 3.3.4.2. (3), the floor assemblies, including floors over basements, that are entirely contained within these dwelling units shall have a fire-resistance rating not less than 1 h but need not be constructed as fire separations. (4) Group A, Division 2 major occupancies, Group E major occupancies and storage garages located in a building or part of a building within the scope of this Article are permitted to be constructed in accordance with this Article, provided, (a) the Group A, Division 2 major occupancy is located below the fourth storey, (b) the Group E major occupancy is located below the third storey, and (c) the storage garage is located below the fifth storey.

(1) A building classified as Group C, other than a retirement home, is permitted to conform to Sentence (2) provided, (a) it is sprinklered, (b) it is not more than 6 storeys in building height, (c) it has a height of not more than 18 m, measured between the floor level of the first storey and the floor level of the uppermost storey or mezzanine that is not a rooftop enclosure provided for elevator machinery, a stairway or a service room used for no purpose other than for service to the building, and (d) it has a building area of not more than, (i) 9 000 m2 if 1 storey in building height, (ii) 4 500 m2 if 2 storeys in building height, (iii) 3 000 m2 if 3 storeys in building height, (iv) 2 250 m2 if 4 storeys in building height, (v) 1 800 m2 if 5 storeys in building height, or (vi) 1 500 m2 if 6 storeys in building height. (2) The building referred to in Sentence (1) is permitted to be of combustible construction or noncombustible construction, used singly or in combination, and, (a) except as permitted by Sentence (3), floor assemblies shall be fire separations with a fire-resistance rating not less than 1 h, (b) roof assemblies shall have a fire-resistance rating not less than 1 h, (c) except as provided by Sentence (4), where the roof assembly has a height greater than 25 m measured from the floor level of the first storey to the highest point of the roof assembly, the roof assembly shall, (i) be of noncombustible construction, or (ii) be constructed of fire-retardant treated wood conforming to Article 3.1.4.5., (d) mezzanines shall have a fire-resistance rating not less than 1 h, (e) [[NO_FORMULA]] Revoked: O. Reg. 89/23, s. 7 (1). (f) loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly. (3) In a building that contains dwelling units that have more than 1 storey, subject to the requirements of Sentence 3.3.4.2. (3), the floor assemblies, including floors over basements, which are entirely contained within these dwelling units, shall have a fire-resistance rating not less than 1 h but need not be constructed as fire separations. (4) The construction of non-contiguous roof assemblies at different elevations is permitted to be evaluated separately to determine which roof assemblies are required to be constructed in accordance with Clause (2)(c). (5) Group A, Division 2 major occupancies, Group E major occupancies and storage garages located in a building or part of a building within the scope of this Article are permitted to be constructed in accordance with this Article, provided, (a) Group A, Division 2 major occupancies and Group E major occupancies are located below the third storey, and (b) storage garages are located below the fourth storey.

(1) A building classified as Group D is permitted to conform to Sentence (2), provided, (a) it is sprinklered, (b) it is not more than 12 storeys in building height, (c) it has a height of not more than 42 m measured between the floor of the first storey and the uppermost floor level that does not serve as a rooftop enclosure for elevator machinery, a stairway or a service room used for no purpose other than for service to the building, and (d) it has a building area not more than 7 200 m2. (2) Except as provided in Article 3.2.2.16., the building referred to in Sentence (1) is permitted to be of encapsulated mass timber construction or nonconbustible construction, used singly or in combination, and, (a) floor assemblies shall be fire separations with a fire-resistance rating not less than 2 h, (b) mezzanines shall have a fire-resistance rating not less than 1 h, and (c) loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly. (3) Group A, Division 2 major occupancies, Group E major occupancies, Group F, Division 2 and 3 major occupancies and storage garages located in a building or part of a building within the scope of this Article are permitted to be constructed in accordance with this Article, provided, (a) the Group A, Division 2 major occupancy is located below the fourth storey, (b) the Group E major occupancy and Group F, Division 2 or 3 major occupancy are located below the third storey, and (c) the storage garage is located below the fifth storey.

(1) A building classified as Group D is permitted to conform to Sentence (2) provided, (a) it is sprinklered, (b) it is not more than 6 storeys in building height, (c) it has a height of not more than 18 m, measured between the floor level of the first storey and the floor level of the uppermost storey or mezzanine that is not a rooftop enclosure provided for elevator machinery, a stairway or a service room used for no purpose other than for service to the building, and (d) it has a building area of not more than, (i) 18 000 m2 if 1 storey in building height, (ii) 9 000 m2 if 2 storeys in building height, (iii) 6 000 m2 if 3 storeys in building height, (iv) 4 500 m2 if 4 storeys in building height, (v) 3 600 m2 if 5 storeys in building height, or (vi) 3 000 m2 if 6 storeys in building height. (2) The building referred to in Sentence (1) is permitted to be of combustible construction or noncombustible construction used singly or in combination, and, (a) floor assemblies shall be fire separations with a fire-resistance rating not less than 1 h, (b) roof assemblies shall have a fire-resistance rating not less than 1 h, (c) except as provided by Sentence (3), where the roof assembly has a height greater than 25 m measured from the floor level of the first storey to the highest point of the roof assembly, the roof assembly shall, (i) be of noncombustible construction, or (ii) be constructed of fire-retardant treated wood conforming to Article 3.1.4.5., (d) mezzanines shall have a fire-resistance rating not less than 1 h, (e) Revoked: O. Reg. 89/23, s. 8 (1). (f) loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly. (3) The construction of non-contiguous roof assemblies at different elevations is permitted to be evaluated separately to determine which roof assemblies are required to be constructed in accordance with Clause (2)(c). (4) Group A, Division 2 major occupancies, Group E major occupancies, Group F, Division 2 and 3 major occupancies and storage garages located in a building or part of a building within the scope of this Article are permitted to be constructed in accordance with this Article, provided, (a) Group A, Division 2 major occupancies, Group E major occupancies and Group F, Division 2 or 3 major occupancies are located below the third storey, and (b) storage garages are located below the fourth storey.