11.4.3.4 — Change in Major Occupancy

(1) Except as provided in Sentence 11.4.2.5. (4), the performance level of an existing building is reduced where proposed construction will result in, (a) the change of the major occupancy of all or part of an existing building to another major occupancy of a greater hazard index, (b) the conversion of a suite of a Group C major occupancy into more than one suite of Group C major occupancy, (c) the conversion of a suite or part of a suite of a Group A, Division 2 or a Group A, Division 4 major occupancy into a gaming premises, (d) the change of a farm building or part of a farm building to a major occupancy, (e) the change of a building or part of a building to a post-disaster building, (f) the change of a building or part of a building to a retirement home, or (g) the change in use of a building or part of a building where the previous major occupancy of the building or part of the building cannot be determined. (2) For the purpose of this Article and Sentences 11.4.2.1. (1) and 11.4.2.5. (4), the change of use set out in Clauses (1)(b) to (g) is also deemed to constitute a change in major occupancy. (3) The performance level of an existing building is reduced where the early warning and evacuation systems requirements of other Parts for the proposed major occupancy exceed those of the existing building. (4) The performance level of an existing building is reduced where the proposed major occupancy in the building is not separated from the adjoining major occupancies by fire separations having fire-resistance ratings conforming to Tables 3.1.3.1. and 11.4.3.4.B. (5) The performance level of an existing building is reduced where the occupancy of all or part of an existing building of combustible construction is changed to a new major occupancy that would require the building, if it were a new building, to be of noncombustible construction or to be constructed in accordance with Article 3.2.2.43A. or 3.2.2.50A. (6) Despite Clause (1)(a), the performance level of an existing building is reduced where proposed construction will result in the change of the major occupancy of all or part of an existing building to a Group C major occupancy in a building over 3 storeys in building height, except in a building conforming to Subclause 3.2.2.44. (1)(a)(ii) and having an egress facility conforming to Sentence 3.3.4.4. (8).

(1) Except as provided by Sentences (2) to (5), major occupancies shall be separated from adjoining major occupancies by fire separations having fire-resistance ratings conforming to Table 3.1.3.1. (2) In a building not more than 3 storeys in building height, if not more than two dwelling units are contained together with a Group E major occupancy, the fire-resistance rating of the fire separation between the two major occupancies need not be more than 1 h. (3) In a building within the scope of Article 3.2.2.42A. or Article 3.2.2.43A., a fire separation with a 2 h fire-resistance rating is required between the Group C and Group A, Division 2 major occupancies. (4) In a building within the scope of Article 3.2.2.49A. or Article 3.2.2.50A., a fire separation with a 2 h fire-resistance rating is required between the Group D and Group A, Division 2 major occupancies. (4.1) In a building within the scope of Article 3.2.2.42A., a fire separation with a 2 h fire-resistance rating is required between the Group C major occupancy and storage garage. (4.2) In a building within the scope of Article 3.2.2.49A., a fire separation with a 1 h fire-resistance rating is required between the Group D and Group E or Group F, Division 2 or 3 major occupancies. (5) The fire separations required between major occupancies in Sentence (1) are permitted to be penetrated by floor openings protected in conformance with Subsection 3.2.8., except for fire separations for Group F, Division 1 major occupancies and for mezzanines described in Sentence 3.2.8.2. (1).

(1) A building classified as Group C, other than a retirement home, is permitted to conform to Sentence (2) provided, (a) it is sprinklered, (b) it is not more than 6 storeys in building height, (c) it has a height of not more than 18 m, measured between the floor level of the first storey and the floor level of the uppermost storey or mezzanine that is not a rooftop enclosure provided for elevator machinery, a stairway or a service room used for no purpose other than for service to the building, and (d) it has a building area of not more than, (i) 9 000 m2 if 1 storey in building height, (ii) 4 500 m2 if 2 storeys in building height, (iii) 3 000 m2 if 3 storeys in building height, (iv) 2 250 m2 if 4 storeys in building height, (v) 1 800 m2 if 5 storeys in building height, or (vi) 1 500 m2 if 6 storeys in building height. (2) The building referred to in Sentence (1) is permitted to be of combustible construction or noncombustible construction, used singly or in combination, and, (a) except as permitted by Sentence (3), floor assemblies shall be fire separations with a fire-resistance rating not less than 1 h, (b) roof assemblies shall have a fire-resistance rating not less than 1 h, (c) except as provided by Sentence (4), where the roof assembly has a height greater than 25 m measured from the floor level of the first storey to the highest point of the roof assembly, the roof assembly shall, (i) be of noncombustible construction, or (ii) be constructed of fire-retardant treated wood conforming to Article 3.1.4.5., (d) mezzanines shall have a fire-resistance rating not less than 1 h, (e) [[NO_FORMULA]] Revoked: O. Reg. 89/23, s. 7 (1). (f) loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly. (3) In a building that contains dwelling units that have more than 1 storey, subject to the requirements of Sentence 3.3.4.2. (3), the floor assemblies, including floors over basements, which are entirely contained within these dwelling units, shall have a fire-resistance rating not less than 1 h but need not be constructed as fire separations. (4) The construction of non-contiguous roof assemblies at different elevations is permitted to be evaluated separately to determine which roof assemblies are required to be constructed in accordance with Clause (2)(c). (5) Group A, Division 2 major occupancies, Group E major occupancies and storage garages located in a building or part of a building within the scope of this Article are permitted to be constructed in accordance with this Article, provided, (a) Group A, Division 2 major occupancies and Group E major occupancies are located below the third storey, and (b) storage garages are located below the fourth storey.

(1) A building classified as Group D is permitted to conform to Sentence (2) provided, (a) it is sprinklered, (b) it is not more than 6 storeys in building height, (c) it has a height of not more than 18 m, measured between the floor level of the first storey and the floor level of the uppermost storey or mezzanine that is not a rooftop enclosure provided for elevator machinery, a stairway or a service room used for no purpose other than for service to the building, and (d) it has a building area of not more than, (i) 18 000 m2 if 1 storey in building height, (ii) 9 000 m2 if 2 storeys in building height, (iii) 6 000 m2 if 3 storeys in building height, (iv) 4 500 m2 if 4 storeys in building height, (v) 3 600 m2 if 5 storeys in building height, or (vi) 3 000 m2 if 6 storeys in building height. (2) The building referred to in Sentence (1) is permitted to be of combustible construction or noncombustible construction used singly or in combination, and, (a) floor assemblies shall be fire separations with a fire-resistance rating not less than 1 h, (b) roof assemblies shall have a fire-resistance rating not less than 1 h, (c) except as provided by Sentence (3), where the roof assembly has a height greater than 25 m measured from the floor level of the first storey to the highest point of the roof assembly, the roof assembly shall, (i) be of noncombustible construction, or (ii) be constructed of fire-retardant treated wood conforming to Article 3.1.4.5., (d) mezzanines shall have a fire-resistance rating not less than 1 h, (e) Revoked: O. Reg. 89/23, s. 8 (1). (f) loadbearing walls, columns and arches shall have a fire-resistance rating not less than that required for the supported assembly. (3) The construction of non-contiguous roof assemblies at different elevations is permitted to be evaluated separately to determine which roof assemblies are required to be constructed in accordance with Clause (2)(c). (4) Group A, Division 2 major occupancies, Group E major occupancies, Group F, Division 2 and 3 major occupancies and storage garages located in a building or part of a building within the scope of this Article are permitted to be constructed in accordance with this Article, provided, (a) Group A, Division 2 major occupancies, Group E major occupancies and Group F, Division 2 or 3 major occupancies are located below the third storey, and (b) storage garages are located below the fourth storey.

(1) A voice communication system required by Subsection 3.2.6., Clause 3.3.2.4. (14)(f) or Sentence 3.3.4.11. (12) shall, (a) consist of a two-way means of communication with the central alarm and control facility and with the mechanical control centre from each floor area, and (b) be capable of broadcasting pre-recorded, synthesized or live messages from the central alarm and control facility that are audible and intelligible in all parts of the building, except in elevator cars. (2) The voice communication system referred to in Sentence (1) shall include a means to silence the alarm signal in a single-stage fire alarm system while voice messages are being transmitted, but only after the alarm signal has initially sounded for not less than 30 s. (3) The voice communication system referred to in Sentence (1) shall include a means to silence the alert signal and the alarm signal in a two-stage fire alarm system while voice messages are being transmitted, but only after the alert signal has initially sounded for not less than, (a) 10 s in hospitals that have supervisory personnel on duty for twenty-four hours each day, or (b) 30 s for all other occupancies. (4) The voice communication system referred to in Sentence (1) shall be designed so that the alarm signal in a two-stage fire alarm system can be selectively transmitted to any zone or zones while maintaining an alert signal or selectively transmitting voice instructions to any other zone or zones in the building. (5) The voice communication system referred to in Sentence (1) shall be designed so that visual signal devices are not interrupted while voice instructions are being transmitted. (6) The voice communication system referred to in Sentence (1) shall be installed so that emergency communication devices are located in each floor area near exit stair shafts. (7) A voice communication system referred to in Sentence (1) that is installed in a building that is not intended to be staffed, at times when the building will be occupied, with persons trained to provide instructions over the system shall include a pre-recorded message.

(1) Except as provided in Sentence (3), all buildings shall be ventilated in accordance with this Part. (2) Except in storage garages and repair garages covered by Article 6.2.2.3., the rates at which outdoor air is supplied in buildings by ventilation systems shall be not less than the rates required by ANSI/ASHRAE 62.1, “Ventilation for Acceptable Indoor Air Quality”. (3) Self-contained mechanical ventilation systems serving a house or an individual dwelling unit shall conform to, (a) this Part, or (b) Subsection 9.32.3. (4) Live/work units shall be mechanically ventilated in accordance with the requirements of Sentence (1).

(1) In a residential occupancy, air from one suite shall not be circulated to any other suite or to a public corridor or public stairway. (2) Except as permitted by Sentence (3) and Sentence 6.2.3.8. (6), air duct systems serving storage garages shall not be directly interconnected with ductwork serving other areas of the building. (3) Where exhaust ducts are provided in conformance with Sentence 6.2.3.8. (6), they may exhaust through an enclosed storage garage prior to exhausting to the outdoors provided, (a) the storage garage exhaust system runs continuously, (b) the capacity of the storage garage exhaust system is equal to or exceeds the volume of the exhaust entering the garage, and (c) a leakage rate 1 smoke/fire damper rated in accordance with CAN/ULC-S112.1, “Leakage Rated Dampers for Use in Smoke Control Systems”, is provided near the duct outlet location in the storage garage to prevent air from the storage garage from entering the exhaust ductwork system in the event the building’s exhaust fan is shut down. (4) Except for corridors conforming to Sentence 3.3.1.4. (4) or as permitted in Sentences (5) and (6), a public corridor or corridor serving the public shall not be used as a portion of a supply, return or exhaust air system serving adjoining areas, other than as part of a supply air system serving toilet rooms, bathrooms, shower rooms and similar auxiliary spaces opening directly to the public corridor or corridor used by the public. (5) A public corridor may be used as part of an engineered smoke control system. (6) Infiltration due to corridor pressurization is permitted into a residential occupancy from a public corridor.

(1) The return-air system shall be designed to handle the entire air supply. (2) Except as provided in Sentences (3) and (4), return ducts shall be constructed of material having a surface flame-spread rating of not more than 150. (3) Where any part of a return duct will be exposed to radiation from the heat exchanger or other radiating part within the furnace, such part of a return duct directly above or within 600 mm of the outside furnace casing shall be noncombustible. (4) Return ducts serving solid fuel-fired furnaces shall be constructed of noncombustible material. (5) Combustible return ducts shall be lined with noncombustible material below floor registers, at the bottom of vertical ducts and under furnaces having a bottom return. (6) Spaces between studs and joists used as return ducts shall be separated from the unused portions of such spaces by tight-fitting metal stops or wood blocking. (7) A vertical return duct shall have openings to return air on not more than 1 floor. (8) A public corridor shall comply with Sentences 6.2.3.9. (4) and (5). (9) The return-air system shall be designed so that the negative pressure from the circulating fan cannot affect the furnace combustion air supply nor draw combustion products from joints or openings in the furnace or flue pipe. (10) Except as provided in Sentence (14), return-air from a dwelling unit shall not be recirculated to any other dwelling unit. (11) Except for floor levels that are less than 900 mm above or below an adjacent floor level that is provided with a return-air inlet, at least one return-air inlet shall be provided in each floor level in a dwelling unit. (12) Provision shall be made for the return of air from all rooms by leaving gaps beneath doors, using louvred doors or installing return duct inlets. (13) Return-air inlets shall not be installed in an enclosed room or crawl space that provides combustion air to a furnace. (14) In a house containing two dwelling units, return-air from one dwelling unit may be recirculated to the other dwelling unit, provided a duct-type smoke detector is installed in the supply or return air duct system serving the entire house which would turn off the fuel supply and electrical power to the heating system upon activation of such detector.