Notes to Table 3.1.3.1.:
3.1.5.26. Combustible Solar Collector Systems (1) A combustible solar collector system is permitted to be installed above the roof of a building required to be of noncombustible construction. 3.1.6. Encapsulated Mass Timber Construction 3.1.6.1. Application (1) Encapsulated mass timber construction permitted in this Part shall conform to this Subsection. 3.1.6.2. Noncombustible Construction (1) Except as otherwise provided in this Part and Sentence 6.2.8.1.(1), materials used in a building
or part of a building
permitted to be of encapsulated mass timber construction shall conform to Subsection 3.1.5. 3.1.6.3. Structural Mass Timber Elements (1) Except as otherwise provided in this Subsection and Articles 3.2.2.16. and 3.2.3.19., a building or part of a building
permitted to be of encapsulated mass timber construction is permitted to include structural mass timber elements, including beams, columns, arches and wall, floor and roof assemblies, provided they comply with Sentences (2) and (3). (2) Structural mass timber elements referred to in Sentence (1) shall, (a) except as provided in Sentence (4), be arranged in heavy solid masses containing no concealed spaces, (b) have essentially smooth flat surfaces with no thin sections or sharp projections, and (c) except as provided in Sentence 3.1.6.17.(1), conform to the minimum dimensions stated in Table 3.1.6.3. Table 3.1.6.3.   Minimum Dimensions of Structural Mass Timber Elements in Encapsulated Mass Timber Construction Forming Part of Sentences 3.1.6.3.(2), 3.1.6.8.(1) and 3.1.6.17.(1)  Item   Column 1   Structural Wood Elements   Column 2   Minimum Thickness, mm   Column 3   Minimum Width x Depth, mm x mm 

  1.   Walls that are not fire separations or exterior walls (1-sided fire exposure)   96   N/A 

  2.   Walls that require a fire-resistance rating, but are not fire separations (2-sided fire exposure)   192   N/A 

  3.   Floors and roofs (1-sided fire exposure)   96   N/A 

  4.   Beams, columns and arches (2- or 3-sided fire exposure)   N/A   192 x 192 

  5.   Beams, columns and arches (4-sided fire exposure)   N/A   224 x 224  (3) Adhesives used in structural mass timber elements referred to in Sentence (1) that are constructed of cross-laminated timber shall conform to the elevated temperature performance requirements in ANSI/APA PRG 320, “Standard for Performance-Rated Cross-Laminated Timber”. (4) Concealed spaces are permitted within structural mass timber elements referred to in Sentence (2) and need not conform to Sentence 3.1.6.4.(1) provided the concealed spaces are, (a)  sprinklered and divided into compartments by fire blocks in conformance with Subsection 3.1.11., (b) completely filled with rocks or slag fibre insulation conforming to CAN/ULC-S702.1 “Standard for Mineral Fibre Thermal Insulation for Buildings, Part 1: Material Specification” and having a density not less than 32 kg/m3, (c) if horizontal, lined with not less than a single layer of 12.7 mm thick Type X gypsum board or noncombustible material providing an encapsulation rating of not less than 25 min, or (d) if vertical, lined with not less than a single layer of 12.7 mm thick Type X gypsum board or noncombustible material providing an encapsulation rating of not less than 25 min and vertically divided into compartments by fire blocks
in conformance with Subsection 3.1.11. 3.1.6.4. Encapsulation of Mass Timber Elements (1) Except as provided in Sentences (3) to (6), Sentence 3.1.6.3.(4), Articles 3.1.6.7. and 3.1.6.12. and Sentences 3.1.6.16.(2) and 3.1.6.17.(2), the exposed surfaces of structural mass timber elements conforming to Article 3.1.6.3. shall be protected from adjacent spaces in the building, including adjacent concealed spaces within wall, floor and roof assemblies, by a material or assembly of materials conforming to Sentence (2) that provides an
encapsulation rating of not less than 50 min. (2) Except as provided in Sentence 3.1.6.11.(1), the material or assembly of materials referred to Sentence (1) shall consist of, (a) gypsum board, (b) gypsum concrete, (c)  noncombustible
materials, (d) materials that conform to Sentences 3.1.5.1.(2) to (4), or (e) any combination of materials listed in Clauses (a) to (d). (3) Except as provided in Sentence (5), the exposed surfaces of mass timber beams, columns and arches within a suite or fire compartment need not be protected in accordance with Sentence (1), provided, (a) the aggregate surface area does not exceed 10% of the total wall area of the perimeter of the suite or fire compartment in which they are located, and (b) the flame-spread rating on any exposed surface is not more than 150. (4) Except as provided in Sentences (5) and (6), the exposed surfaces of mass timber walls within a suite need not be protected in accordance with Sentence (1), provided, (a) each exposed surface faces the same direction, and (b) the flame-spread rating on any exposed surface is not more than 150. (5) The aggregate exposed surface area of mass timber elements within a suite permitted in Sentences (3) and (4) shall not exceed 35% of the total wall area of the perimeter of the suite. (6) The exposed surfaces of mass timber ceilings within a suite
need not be protected in accordance with Sentence (1), provided the aggregate area of the exposed surfaces does not exceed, (a) 10% of the total ceiling area of the suite, where the exposed surfaces have a flame-spread rating not more than 150, or (b) 25% of the total ceiling area of the suite, where, (i) the suite contains no mass timber walls with exposed surfaces, and (ii) the exposed surfaces of the mass timber ceiling have a flame-spread rating
not more than 75. 3.1.6.5. Determination of Encapsulation Ratings (1) Except as provided in Article 3.1.6.6., the rating of a material or assembly of materials that is required to have an encapsulation rating shall be determined on the basis of the results of the tests conducted in conformance with CAN/ULC-S146, “Test for the Evaluation of Encapsulation Materials and Assemblies of Materials for the Protection of Structural Timber Elements”. 3.1.6.6. Encapsulation Materials (1) Gypsum-concrete topping and concrete not less than 38 mm thick are deemed to have an encapsulation rating of 50 min when installed on the upper side of a mass timber floor or roof assembly. (2) Two layers of Type X gypsum board each not less than 12.7 mm thick are deemed to have an encapsulation rating of 50 min when installed on a mass timber element, provided they, (a) are fastened with a minimum of two rows of screws in each layer, (i) directly to the mass timber element with screws of sufficient length to penetrate not less than 20 mm into the mass timber element that are spaced not more than 400 mm o.c. and 20 mm to 38 mm from the boards’ edges, or (ii) to wood furring or resilient metal or steel furring channels not more than 25 mm thick spaced not more than 400 mm o.c. on the mass timber element, (b) are installed with the joints in each layer staggered from those in the adjacent layer, (c) are installed in conformance with ASTM C840, “Standard Specification for Application and Finishing of Gypsum Board”, except that their joints need not be taped and finished, and (d) conform to, (i) ASTM C1396/C1396M, “Gypsum Board”, or (ii) CAN/CSA A82.27-M, “Gypsum Board”. 3.1.6.7. Combustible Roofing Materials (1) Wood roof sheathing and roof sheathing supports that do not conform to Articles 3.1.6.3. and 3.1.6.4. are permitted in a building
or part of a building permitted to be of encapsulated mass timber construction, provided they are installed, (a) above a concrete deck in accordance with Clauses 3.1.5.3.(2)(a) to (f), or (b) above a deck of encapsulated mass timber construction, where, (i) the deck is permitted to be encapsulated between the roof sheathing supports by a material or assembly of materials conforming to Sentence 3.1.6.4.(2) that provides an encapsulation rating of not less than 50 min, (ii) the height of the roof space is not more than 1 m, (iii) the roof space is divided into compartments by fire blocks in conformance with Article 3.1.11.5., (iv) openings through the deck other than for noncombustible roof drains and plumbing piping are protected by shafts constructed as fire separations having a fire-resistance rating not less than 1 h that extend from the deck to not less than 150 mm above the adjacent sheathing, and (v) except as permitted by Subclause (iv), the roof space does not contain any building
services. (2) Combustible cant strips, roof curbs, nailing strips and similar components used in the installation of roofing are permitted on a building
or part of a building permitted to be of encapsulated mass timber construction. (3) Wood nailer facings to parapets that are not more than 610 mm high are permitted on a building or part of a building
permitted to be of encapsulated mass timber construction, provided the facings and any roof membranes covering the facings are protected by sheet metal. 3.1.6.8. Combustible Window Sashes and Frames (1) Combustible window sashes and frames are permitted in a building or part of a building permitted to be of encapsulated mass timber construction, provided, (a) each window in an exterior wall face is an individual unit separated from every other opening in the wall by noncombustible wall construction or mass timber wall construction conforming to the dimensions stated in Table 3.1.6.3., (b) windows in exterior walls in contiguous storeys are separated by not less than 1 m of noncombustible wall construction or mass timber wall construction conforming to the dimensions stated in Table 3.1.6.3., and (c) the aggregate area of openings in an exterior wall face of a fire compartment is not more than 40% of the area of the wall face. 3.1.6.9. Exterior Cladding (1) Except as provided in Sentences (2), (3) and (6), cladding on an exterior wall assembly of a building or part of a building permitted to be of encapsulated mass timber construction shall be noncombustible. (2) Except as provided in Sentences (3) to (5), cladding on an exterior wall assembly of a building or part of a building
permitted to be of encapsulated mass timber construction
is permitted to consist of, (a)  combustible cladding that, (i) is not contiguous over more than 4 storeys, (ii) represents not more than 10% of the cladding on each exterior wall of each storey, (iii) is not more than 1.2 m in width, (iv) has a flame-spread rating not more than 75 on any exposed surface, or any surface that would by exposed by cutting through the material in any direction, (v) is separated from other portions of combustible cladding on adjacent storeys by a horizontal distance of not less than 2.4 m, and (vi) is separated from other portions of combustible cladding by a horizontal distance of not less than 1.2 m, (b)  combustible cladding that, (i) is not contiguous across adjacent storeys, (ii) represents not more than 10% of the cladding on each exterior wall of each storey, (iii) has a flame-spread rating not more than 75 on any exposed surface, or any surface that would be exposed by cutting through the material in any direction, and (iv) is separated from other portions of combustible cladding on adjacent storeys by a horizontal distance of not less than 2.4 m, (c)  combustible cladding representing up to 100% of the cladding on exterior walls of the first
storey, provided all portions of the cladding can be directly accessed and are located not more than 15 m from a street or access route conforming to Article 3.2.5.6., measured horizontally from the face of the building, (d) except as provided in Sentence (4), a wall assembly that satisfies the criteria described in Clause 3.1.5.5.(1)(b), or (e) a combination of noncombustible cladding and the cladding described in Clauses (a) to (d). (3) The permitted area of combustible cladding referred to in Clause (2)(a) or (b) shall not exceed 5% of the cladding on each exterior wall of each
storey where firefighting facilities cannot reach the building within 10 min of the alarm being received. (4) An exterior wall assembly constructed in conformance with Section 6 of MMAH Supplementary Standard SB-2, “Fire Performance Ratings” is deemed to satisfy the criteria of Clause (2)(d). (5) Except as provided in Article 3.2.3.10., where the limiting distance
in Table 3.2.3.1.D. or Table 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. (6) A wall assembly conforming to Clause (2)(d) that includes combustible
cladding made of fire-retardant-treated wood shall be tested for fire exposure after the cladding has been subjected to the accelerated weathering test specified in ASTM D2898, “Accelerated Weathering of Fire-Retardant-Treated Wood for Fire Testing”. (7) Where combustible cladding conforming to Clause (2)(a) or (b) on an exterior wall of a fire compartment is exposed to combustible cladding conforming to Clause (2)(a) or (b) on an exterior wall of the same fire compartment
or of another fire compartment, and the planes of the two walls are parallel or at an angle less than 135° measured from the exterior of the building, the different portions of
combustible cladding shall, (a) be separated by a horizontal distance of not less than 3 m, and (b) not be contiguous over more than 2
storeys. 3.1.6.10. Combustible Components in Exterior Walls (1) Except as provided in Sentence (2), combustible
components, other than those permitted by Article 3.1.6.9., are permitted to be used in an exterior wall assembly of a building
or part of a building permitted to be of encapsulated mass timber construction provided the wall assembly meets the requirements of Clause 3.1.6.9.(2)(d). (2) An exterior wall assembly constructed in conformance with Section 6 in MMAH Supplementary Standard SB-2, “Fire Performance Ratings” is deemed to satisfy the criteria of Sentence (1). (3) Non-loadbearing wood elements permitted in Article 3.1.5.5. need not conform to Article 3.1.6.3. in a building or part of a building permitted to be of encapsulated mass timber construction. 3.1.6.11. Nailing Elements (1) Wood nailing elements are permitted to be used for the attachment of a material or assembly of materials to provide an encapsulation rating in a building or part of a building
permitted to be of encapsulated mass timber construction, provided the concealed space created by the wood nailing elements is not more than 25 mm deep. (2) Except as permitted by Sentence 3.1.6.16.(2) and Article 3.1.6.6., wood nailing elements are permitted to be used for the attachment of interior finishes in a building or part of a building
permitted to be of encapsulated mass timber construction, provided the concealed space created by the wood nailing elements is not more than 50 mm deep and, (a) exposed surfaces in the concealed space have a flame-spread rating not more than 25, or (b) the concealed space is filled with
noncombustible insulation. 3.1.6.12. Combustible Flooring Elements (1) Wood members that are more than 50 mm but not more than 300 mm high are permitted to be used for the construction of a raised platform in a building or part of a building
permitted to be of encapsulated mass timber construction, and they need not conform to Articles 3.1.6.3. and 3.1.6.4., provided, (a) the concealed spaces created by the wood members are divided into compartments by fire blocks in conformance with Sentence 3.1.11.3.(4), and (b) the wood members are, (i) applied directly to or set into a noncombustible floor slab, or (ii) applied directly to a mass timber floor assembly that conforms to the requirements of Article 3.1.6.3. (2) The upper surface of the mass timber floor assembly referred to in Subclause (1)(b)(ii) is permitted to be encapsulated only between the wood members by a material or assembly of materials conforming to Sentences 3.1.6.4.(1) and (2). (3) The floor system for the raised platform referred to in Sentence (1) is permitted to include a combustible subfloor and combustible
finished flooring. 3.1.6.13. Combustible Stairs (1) Wood stairs and landings conforming to the requirements for floor assemblies in Article 3.1.6.3. and Sentences 3.1.6.4.(1) and (2) are permitted in an exit stairwell in a building
or part of a building permitted to be of encapsulated mass timber construction. (2) Wood stairs in a suite in a building or part of a building permitted to be of encapsulated mass timber construction need not conform to Articles 3.1.6.3. and 3.1.6.4. 3.1.6.14. Combustible Interior Finishes (1) Except as provided in Sentences (2) and (3), combustible
interior wall and ceiling finishes referred to in Clause 3.1.13.1.(1)(b) that are not more than 1 mm thick are permitted in a building
or part of a building permitted to be of encapsulated mass timber construction. (2) Except as provided in Sentences 3.1.6.4.(3) and (4), combustible interior wall finishes, other than foamed plastics, that are not more than 25 mm thick are permitted in a building or part of a building permitted to be of encapsulated mass timber construction, provided they have a flame-spread rating not more than 150 on any exposed surface or any surface that would be exposed by cutting through the material in any direction. (3) Except as provided in Sentences (4) and 3.1.6.4.(3) and (6), combustible
interior ceiling finishes, other than foamed plastics, are permitted in a building or part of a building
permitted to be of encapsulated mass timber construction, provided that, (a) they have a flame-spread rating not more than 25 on any exposed surface or any surface that would be exposed by cutting through the material in any direction, and (b) not more than 10% of the ceiling area within each fire compartment is permitted to have a flame-spread rating not more than 150. (4) Combustible interior ceiling finishes made of fire-retardant-treated wood are permitted in a building or part of a building
permitted to be of encapsulated mass timber construction, provided they are not more than 25 mm thick or are exposed fire-retardant-treated wood battens. 3.1.6.15. Combustible Elements in Partitions (1) Solid lumber partitions not less than 38 mm thick and partitions containing wood framing that do not conform to Article 3.1.6.3. are permitted in a building or part of a building
permitted to be of encapsulated mass timber construction, provided the partitions are, (a) protected on each face with not less than, (i) a single layer of 12.7 mm thick Type X gypsum board, with all joints either backed or taped and filled, conforming to ASTM C1396/C1396M, “Standard Specification for Gypsum Board”, or CAN/CSA A82.27-M, “Gypsum Board”, (ii) a single layer of 19 mm thick fire-retardant-treated wood, on solid lumber partitions, or (iii) a single layer of 19mm thick fire-retardant-treated wood, on partitions containing wood framing, with wood stud cavities filled with noncombustible insulation, and (b) not installed as enclosures for exits or vertical service spaces. 3.1.6.16. Exposed Construction Materials and Components in Concealed Spaces (1) Except as provided in Sentence (2) and Article 3.1.11.7., and except as otherwise provided in this Subsection, only construction materials and components permitted in noncombustible construction
shall be permitted to have exposed surfaces in concealed spaces within floor, roof and wall assemblies permitted in a building or part of a building permitted to be of encapsulated mass timber construction. (2) Exposed surfaces are permitted in a concealed space created by the attachment of a material or assembly of materials conforming to Sentence 3.1.6.4.(1), provided the concealed space is not more than 25 mm deep. 3.1.6.17. Penetration by Outlet Boxes (1) The minimum dimensions stated in Table 3.1.6.3. need not apply at cutouts in vertical or horizontal structural mass timber elements where outlet boxes are installed in accordance with Article 3.1.9.3A. (2) The exposed surfaces of the cutouts described in Sentence (1) need not be protected in accordance with Sentence 3.1.6.4.(1). (3) Outlet boxes on opposite sides of a structural mass timber element having a fire-resistances rating shall be separated by a distance of not less than 600 mm. 3.1.7. Fire-Resistance Ratings