| 3.2.8. |
Mezzanines and Openings through Floor Assemblies |
| 3.2.8.1. |
Application
- Except as permitted by Article 3.2.8.2. and Sentence 3.3.4.2.(3), the portions of a floor area or a mezzanine that do not terminate at an exterior wall, a firewall or a vertical shaft shall
- terminate at a vertical fire separation having a fire-resistance rating not less than that required for the floor assembly and extending from the floor assembly to the underside of the floor or roof assembly above, or
- be protected in conformance with the requirements of Articles 3.2.8.3. to 3.2.8.8.
- The penetration of a floor assembly by an exit or a vertical service space shall conform to the requirements of Sections 3.4., 3.5. and 3.6.
- A floor area containing sleeping rooms in a building of Group B, Division 2 major occupancy shall not be constructed as part of an interconnected floor space.
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| 3.2.8.2. |
Exceptions to Special Protection
- A mezzanine need not terminate at a vertical fire separation nor be protected in conformance with the requirements of Articles 3.2.8.3. to 3.2.8.8. provided the mezzanine
- serves a Group A, Division 1 major occupancy,
- serves a Group A, Division 3 major occupancy in a building not more than 2 storeys in building height, or
- serves a Group A, C, D, E or F major occupancy and
- is 500 m2 or less in area, and
- conforms to Sentence 3.2.1.1.(3) or (4).
- Except for floors referred to in Sentence 3.1.10.3.(1) and Article 3.2.1.2., openings through a horizontal fire separation for vehicular ramps in a storage garage are not required to be protected with closures and need not conform to this Subsection.
- If a closure in an opening in a fire separation would disrupt the nature of a manufacturing process, such as a continuous flow of material from storey to storey, the closure for the opening is permitted to be omitted provided precautions are taken to offset the resulting hazard. (See Note A-3.2.8.2.(3).)
- An interconnected floor space in a Group B, Division 1 occupancy need not conform to the requirements of Articles 3.2.8.3. to 3.2.8.8. provided the interconnected floor space does not interconnect more than 2 adjacent storeys.
- Except as permitted by Sentence (6), openings for escalators and inclined moving walks need not conform to the requirements in Articles 3.2.8.3. to 3.2.8.8. provided
- the opening for each escalator or walk does not exceed 10 m2,
- the building is sprinklered throughout, and
- the interconnected floor space contains only Group A, Division 1, 2 or 3, Group D or Group E major occupancies (see Note A-3.2.8.2.(6)(c)).
- An interconnected floor space need not conform to the requirements of Articles 3.2.8.3. to 3.2.8.8., provided
- it consists of the first storey and the storey next above or below it, but not both,
- it is sprinklered throughout or, where the building area is not more than one half of the area permitted by Subsection 3.2.2., the openings through the floor are used only for stairways, escalators or moving walks (see Note A-3.2.8.2.(6)(b)), and
- it contains only Group A, Division 1, 2 or 3, Group D, Group E, or Group F, Division 2 or 3 major occupancies (see Note A-3.2.8.2.(6)(c)).
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| 3.2.8.3. |
Sprinklers
- A building containing an interconnected floor space shall be sprinklered throughout.
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| 3.2.8.4. |
Vestibules
- An exit opening into an interconnected floor space shall be protected at each opening into the interconnected floor space by a vestibule
- with doorways that are not less than 1.8 m apart,
- that is separated from the remainder of the floor area by a fire separation that is not required to have a fire-resistance rating (see Note A-3.1.8.1.(1)(b)), and
- that is designed to limit the passage of smoke so that the exit stair shaft does not contain more than 1% by volume of contaminated air from the fire floor, assuming an outdoor temperature equal to the January design temperature on a 2.5% basis determined in accordance with Subsection 1.1.3. (see Note A-3.2.8.4.(1)(c)).
- An exit opening into an interconnected floor space shall conform to Sentence 3.4.3.2.(6).
- If an elevator hoistway opens into an interconnected floor space and into storeys above the interconnected floor space, either the elevator doors opening into the interconnected floor space or the elevator doors opening into the storeys above the interconnected floor space shall be protected by vestibules conforming to Sentence (1).
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| 3.2.8.5. |
Protected Floor Space
- A protected floor space used to satisfy the requirements of Clause 3.4.3.2.(6)(b) shall
- be separated from the interconnected floor space by a fire separation having a fire-resistance rating not less than that required for the floor assembly of the storey in which it is located,
- have all openings in the vertical fire separation between a protected floor space and the adjacent interconnected floor space protected by vestibules conforming to Sentence 3.2.8.4.(1), and
- be designed so that it is not necessary to enter the interconnected floor space to reach an exit.
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| 3.2.8.6. |
Draft Stops
- A draft stop shall be provided at each floor level within an interconnected floor space, immediately adjacent to and surrounding the opening, and shall be not less than 500 mm deep measured from ceiling level down to the underside of the draft stop.
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| 3.2.8.7. |
Mechanical Exhaust System
- A mechanical exhaust system shall be provided to remove air from an interconnected floor space at a rate of 4 air changes per hour. (See Note A-3.2.8.7.(1).)
- The mechanical exhaust system required by Sentence (1) shall be actuated by a switch located on the storey containing the entrance for firefighter access referred to in Articles 3.2.5.4. and 3.2.5.5. near the annunciator for the fire alarm system.
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| 3.2.8.8. |
Combustible Content Limits
- An interconnected floor space shall be designed so that the combustible contents, excluding interior finishes, in those parts of a floor area in which the ceiling is more than 8 m above the floor, are limited to not more than 16 g of combustible material for each cubic metre of volume of the interconnected floor space.
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