National Building Code of Canada - Section 255

3.2.8.1. Division B the hose stream application, to provide a circuit integrity rating of not less than 2 h (see Note A-3.2.7.10.(2)(a) and (3)(a)), or b) be located in a service space that is separated from the remainder of the building by a fire separation that has a fire-resistance rating not less than 2 h. 4) The service spaces referred to in Clauses (2)(b) and (3)(b) shall not contain any combustible materials other than the conductors being protected. 5) Except as stated in Sentences (7) and (9), th e electrical conductors referred to in Sentence (1) are those that extend from the source of emergency power to a) the equipment served, or b) the distribution equipment supplying power to the equipment served, if both are in the same room (see Note A-3.2.7.10.(5)(b)). 6) If a fire alarm transponder or annunciator in one fire compartment is connected to a central processing unit or another transponder or annunciator located in a different fire compartment , the electrical conductors connecting them shall be protected in accordance with Sentence (2). 7) Fire alarm system branch circuits within a storey that connect transponders to individual devices need not conform to S entence (2). (See Note A-3.2.7.10.(7).) 8) Except as permitted in Sentence (9), if a distribution panel supplies power to emergency lighting, the power supply conductors leading up to the distribution panel shall be protected in accordance with Sentence (2). 9) Conductors leading from a distribution panel referred to in Sentence (8) to emergency lighting units in the same storey need not conform to Sentence (2). 10) Distribution panels serving emergency lighting units located on other storeys shall be installed in a service room separated from the floor area by a fire separation having a fire-resistance rating of at least 1 h. 11) Conduc tors leading from a distribution panel to emergency lighting units located on other storeys shall be protected in accordance with Sentence (2) between the distribution panel and the floor area where the emergency lighting units are located. 3.2.8. Mezzanines and Openings through Floor Assemblies 3.2.8.1. Application 1) 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 a) 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 b) be protected in conformance with the requirements of Articles 3.2.8.3. to 3.2.8.8. 2) 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. 3) 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 . 3.2.8.2. Exceptions to Special Protection 1) 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 a) serves a Group A, Division 1 major occupancy , b) serves a Group A, Division 3 major occupancy in a building not more than 2 storeys in building height, or c) serves a Group A, C, D, E or F major occupancy and i) is 500 m 2 or less in area, and ii) conforms to Sentence 3.2.1.1.(3) or (4). 3-116 Division B National Building Code of Canada 2025 Volume 1