9.10.16. Fire Blocks

9.10.16. Fire Blocks
9.10.16.1. Required Fire Blocks in Concealed Spaces
  1. Vertical concealed spaces in interior walls and exterior walls shall be separated by fire blocks
    1. one from the other, and
    2. from horizontal concealed spaces.
  2. Horizontal concealed spaces in attics, roof spaces, ceilings, floors, and crawl spaces shall be separated by fire blocks
    1. one from the other, and
    2. from vertical concealed spaces.
  3. Fire blocks shall be provided at all interconnections between concealed vertical and horizontal spaces in interior coved ceilings, drop ceilings and soffits where the exposed construction materials within the concealed spaces have a surface flame-spread rating greater than 25.
  4. Fire blocks shall be provided at the top and bottom of each run of stairs where they pass through a floor containing concealed space in which the exposed construction materials within the space have a surface flame-spread rating greater than 25.
  5. Unsprinklered concealed spaces of combustible construction created by a ceiling, roof space or unoccupied attic space shall be separated by fire blocks into compartments
    1. not more than 60 m in greatest dimension, and
    2. where such space contains exposed construction materials having a surface flame-spread rating greater than 25, not more than 300 m2 in area.
  6. No dimension of the concealed space described in Clause (5)(b) shall exceed 20 m.
  7. Concealed spaces in mansard or gambrel style roofs, exterior cornices, balconies and canopies of combustible construction in which the exposed construction materials within the space have a surface flame-spread rating exceeding 25 shall have vertical fire blocks at intervals of not more than 20 m and at points where such concealed spaces extend across the ends of required vertical fire separations.
9.10.16.2. Required Fire Blocks in Wall Assemblies
  1. Except as permitted in Sentence (2), fire blocks shall be provided to block off concealed spaces within wall assemblies, including spaces created by furring,
    1. at each floor level,
    2. at each ceiling level where the ceiling contributes to part of the required fire-resistance rating, and
    3. at other locations within the wall, so that the distance between fire blocks does not exceed 20 m horizontally and 3 m vertically.
  2. Fire blocks described in Sentence (1) are not required, provided
    1. the insulated wall assembly contains not more than one concealed air space whose horizontal thickness is not more than 25 mm,
    2. the exposed construction materials within the space are noncombustible,
    3. the exposed construction materials within the space, including insulation, but not including wiring, piping or similar services, have a flame-spread rating of not more than 25, or
    4. the concealed wall space is filled with insulation.
9.10.16.3. Fire Block Materials
  1. Except as permitted by Sentences (2) and (3), fire blocks shall be constructed of materials that will 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. Fire blocks are deemed to comply with Sentence (1) if they are constructed of not less than
    1. 0.38 mm sheet steel,
    2. 12.7 mm gypsum board,
    3. 12.5 mm plywood, OSB or waferboard, with joints having continuous supports,
    4. 2 layers of 19 mm lumber with joints staggered, or
    5. 38 mm lumber.
  3. 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 floor assembly and the walls, provided the width of the vertical space does not exceed 25 mm and the insulation board
    1. has a density not less than 45 kg/m3,
    2. is securely fastened to one set of studs,
    3. 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
    4. completely fills the portion of the vertical space between the headers and between the wall plates. (See Note A-3.1.11.7.(7).)
9.10.16.4. Penetration of Fire Blocks
  1. Where fire blocks are pierced by pipes, ducts or other elements, the effectiveness of the fire blocks shall be maintained around such elements.

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