| 3.1.10. |
Firewalls |
| 3.1.10.1. |
Prevention of Firewall Collapse
- Except as permitted by Sentence (2), the connections and supports for structural framing members that are connected to or supported on a firewall and have a fire-resistance rating less than that required for the firewall, shall be designed so that the failure of the framing systems during a fire will not affect the integrity of the firewall during the fire.
- Sentence (1) does not apply to a firewall consisting of two separate wall assemblies each tied to its respective building frame but not to each other, provided each wall assembly is
- a fire separation having one half of the fire-resistance rating required for the firewall by Sentences 3.1.10.2.(1) and (2), and
- designed so that the collapse of one wall assembly will not cause collapse of the other.
- A firewall is permitted to be supported on the structural frame of a building of noncombustible construction provided the supporting frame has a fire-resistance rating not less than that required for the firewall.
- Piping, ducts and totally enclosed noncombustible raceways shall be installed so that their collapse will not cause collapse of the firewall.
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| 3.1.10.2. |
Rating of Firewalls
- A firewall that separates a building or buildings with floor areas containing a Group E or a Group F, Division 1 or 2 major occupancy shall be constructed as a fire separation of noncombustible construction having a fire-resistance rating not less than 4 h, except that where the upper portion of a firewall separates floor areas containing other than Group E or Group F, Division 1 or 2 major occupancies, the fire-resistance rating of the upper portion of the firewall is permitted to be not less than 2 h.
- A firewall that separates a building or buildings with floor areas containing major occupancies other than Group E or Group F, Division 1 or 2 shall be constructed as a fire separation of noncombustible construction having a fire-resistance rating not less than 2 h.
- Except as permitted by Sentence (4), the required fire-resistance rating of a firewall, except for closures, shall be provided by masonry or concrete.
- A firewall permitted to have a fire-resistance rating not more than 2 h need not be constructed of masonry or concrete, provided
- the assembly providing the fire-resistance rating is protected against damage that would compromise the integrity of the assembly, and
- the design conforms to Article 4.1.5.17. (See Note A-3.1.10.2.(4).)
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| 3.1.10.3. |
Continuity of Firewalls
- A firewall shall extend from the ground continuously through, or adjacent to, all storeys of a building or buildings so separated, except that a firewall located above a basement storage garage conforming to Article 3.2.1.2. is permitted to commence at the floor assembly immediately above the storage garage. (See also Sentence 3.1.10.1.(3).)
- A firewall is permitted to terminate on the underside of a reinforced concrete roof slab, provided
- the roof slab on both sides of the firewall has a fire-resistance rating not less than
- 1 h if the firewall is required to have a fire-resistance rating not less than 2 h, or
- 2 h if the firewall is required to have a fire-resistance rating not less than 4 h, and
- there are no concealed spaces within the roof slab in that portion immediately above the firewall.
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| 3.1.10.4. |
Parapets
- Except as permitted by Sentences (2) and 3.1.10.3.(2), a firewall shall extend above the roof surface to form a parapet not less than
- 150 mm high for a firewall required to have a fire-resistance rating not less than 2 h, and
- 900 mm high for a firewall required to have a fire-resistance rating not less than 4 h.
- A firewall that separates 2 buildings with roofs at different elevations need not extend above the upper roof surface to form a parapet, provided the difference in elevation between the roofs is more than 3 m.
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| 3.1.10.5. |
Maximum Openings
- Openings in a firewall shall conform to the size limits described in Article 3.1.8.6. and the aggregate width of openings shall be not more than 25% of the entire length of the firewall.
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| 3.1.10.6. |
Exposure Protection for Adjacent Walls
- The requirements of Article 3.2.3.14. shall apply to the external walls of 2 buildings that meet at a firewall at an angle less than 135°.
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| 3.1.10.7. |
Combustible Projections
- Combustible material shall not extend across the end of a firewall but is permitted to extend across a roof above a firewall that is terminated in conformance with Sentence 3.1.10.3.(2).
- If buildings are separated by a firewall, combustible projections on the exterior of one building, including balconies, platforms, canopies, eave projections and stairs, that extend outward beyond the end of the firewall, shall not be permitted within 2.4 m of combustible projections and window or door openings of the adjacent building. (See also Article 3.2.3.6.)
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