Last updated
Values this chapter turns on
- floor area per person in offices
- 9.30 m²
- floor area per person in offices
- floor area per person in standing space
- 0.40 m²
- floor area per person in standing space
- max restaurant size that may be Group E
- 30 persons
- max restaurant size that may be Group E
- separation between Group D or E and F1
- 3 h
- separation between Group D or E and F1
Every Part 3 fire protection question starts with classification. The major occupancy decides the construction article, the fire alarm trigger, the sprinkler rules and the separations between uses. This chapter covers how to classify, how to separate different major occupancies, which combinations are banned, which combustible items are tolerated in noncombustible buildings, and how to compute occupant load.
Classification of buildings by major occupancy
Each building or part is classified by major occupancy into the Groups and Divisions of Table 3.1.2.1.OBC Div. B Table 3.1.2.1. Major Occupancy ClassificationTable 3.1.2.1. Major Occupancy Classification Forming Part of Sentences 3.1.2.1.(1), 3.1.2.2.(1) and 3.11.2.1.(3) Group | Division | Description of Major Occupancy A | 1 | Assembly occupancies intended for the production and viewing of the performing arts A | 2 | Assembly occupancies not elsewhere classified in Group…, and a building with several major occupancies is classified by all of them (OBC Div. B 3.1.2.1.OBC Div. B 3.1.2.1. Classification of Buildings(1) Except as permitted by Articles 3.1.2.3. to 3.1.2.7., every building or part thereof shall be classified according to its major occupancy as belonging to one of the Groups or Divisions described in Table 3.1.2.1. (See Note A-3.1.2.1.(1)) (2) A building intended for use by more than one major occupancy shall be…). If every occupancy falls in the same Group (or same Division where the Group is divided), the building is treated as one major occupancy (3.1.2.2.OBC Div. B 3.1.2.2. Occupancies of the Same Classification(1) Any building is deemed to be occupied by a single major occupancy, notwithstanding its use for more than one major occupancy, provided that all occupancies are classified as belonging to the same Group classification or, where the Group is divided into Divisions, as belonging to the same Division classification…).
Several special classification rules appear in exam questions:
| Situation | Classification permitted | Article |
|---|---|---|
| Arena used occasionally for trade shows | A3 (required) | 3.1.2.3.OBC Div. B 3.1.2.3. Arena-Type Buildings(1) An arena-type building intended for occasional use for trade shows and similar exhibition purposes shall be classified as Group A, Division 3 occupancy. |
| Police station with detention, 1 storey, max 600 m² | B2 | 3.1.2.4.OBC Div. B 3.1.2.4. Police Stations(1) A police station with detention quarters is permitted to be classified as a Group B, Division 2 major occupancy provided the station is not more than 1 storey in building height and 600 m² in building area. |
| Care suite, max 10 persons, max 2 needing evacuation help | Group C | 3.1.2.5.OBC Div. B 3.1.2.5. Group B, Division 3 Occupancies(1) Group B, Division 3 occupancies are permitted to be classified as Group C major occupancies within the application of Part 3 provided (a) the occupants live as a single housekeeping unit in a suite with sleeping accommodation for not more than 10 persons, and (b) not more than two occupants require assistance in… |
| Baled combustible fibre storage | F2 (required) | 3.1.2.6.OBC Div. B 3.1.2.6. Storage of Combustible Fibres(1) Buildings or parts of thereof used for the storage of baled combustible fibres shall be classified as medium-hazard industrial occupancies. |
| Restaurant for max 30 persons eating or drinking | Group E | 3.1.2.7.OBC Div. B 3.1.2.7. Restaurants(1) A restaurant is permitted to be classified as a Group E major occupancy within the application of Part 3 provided the restaurant is designed to accommodate not more than 30 persons consuming food or drink. |
Note the wording: most of these are "permitted", so the designer may still use the stricter class. The arena and fibre storage rules are mandatory.
Separation of major occupancies and prohibited combinations
Adjoining major occupancies are separated by fire separations rated per Table 3.1.3.1.OBC Div. B Table 3.1.3.1. Major Occupancy Fire Separations—Minimum Fire-Resistance Rating of Fire Separation, h[1]Table 3.1.3.1. Major Occupancy Fire Separations—Minimum Fire-Resistance Rating of Fire Separation, h[1] Forming Part of Sentence 3.1.3.1.(1) Major Occupancy | Adjoining Major Occupancy A-1 | Adjoining Major Occupancy A-2 | Adjoining Major Occupancy A-3 | Adjoining Major Occupancy A-4 | Adjoining Major Occupancy B-1 |… (OBC Div. B 3.1.3.1.OBC Div. B 3.1.3.1. Separation of Major Occupancies(1) Except as permitted by Sentences (2) and (3), 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…). Read the table by finding the row for one occupancy and the column for the other; the result is in hours. Some entries are N/A (no separation needed between them, for example Group D and Group E), some point to notes. A few values to practise:
| Pair | Minimum rating |
|---|---|
| A2 and C | 1 h (2 h under the 3.2.2.51. note) |
| B1 and almost anything | 2 h |
| C and E | 2 h, or 1 h under 3.1.3.1.(2) |
| D or E and F1 | 3 h |
| D and E | none (N/A) |
Sentence (2) lowers the C to E separation to 1 h in a building not more than 3 storeys with not more than two dwelling units. Sentence (3) drops the major occupancy separation at the vertical plane around an interconnected floor space opening that meets 3.2.8.
Prohibited combinations (OBC Div. B 3.1.3.2.OBC Div. B 3.1.3.2. Prohibition of Occupancy Combinations(1) No major occupancy of Group F, Division 1 shall be contained within a building with any occupancy classified as Group A, B or C. (2) Except as provided in Sentence (4) and Sentence 3.10.2.4.(9), not more than one suite of residential occupancy shall be contained within a building classified as a Group F, Division…):
- F1 cannot share a building with Group A, B or C.
- An F2 building may contain not more than one residential suite (live/work buildings are an exception).
- A building under 3.2.2.51. or 3.2.2.60. (the 6-storey sprinklered combustible construction articles for Groups C and D) may not contain a retirement home.
Combustible and noncombustible materials
A building permitted to be of combustible construction may use combustible materials, with or without noncombustible components (OBC Div. B 3.1.4.1.OBC Div. B 3.1.4.1. Combustible Materials Permitted(1) A building permitted to be of combustible construction is permitted to be constructed of combustible materials, with or without noncombustible components. (See Note A-3.1.4.1.(1))). In those buildings, wires and cables with combustible jackets must pass the FT1 vertical flame test or be enclosed in raceways, masonry or concrete; in plenums, voice and data cables need the FT6 rating, with fire alarm signal cables exempt (3.1.4.3.OBC Div. B 3.1.4.3. Wires and Cables(1) Except as required by Sentence (2), optical fibre cables and electrical wires and cables with combustible insulation, jackets or sheathes installed in a building permitted to be of combustible construction shall (a) not convey flame or continue to burn for more than 1 min when tested in conformance with the…, 3.1.4.4.OBC Div. B 3.1.4.4. Non-metallic Raceways(1) Totally enclosed non-metallic raceways used in a plenum in a building permitted to be of combustible construction shall meet the requirements of Clause 3.1.5.23.(1)(a).).
A building required to be noncombustible must use noncombustible materials, except where 3.1.5.2. to 3.1.5.29. permit otherwise (OBC Div. B 3.1.5.1.OBC Div. B 3.1.5.1. Noncombustible Materials)(1) Except as permitted by Sentences (2) to (4) and Articles 3.1.5.2. to 3.1.5.29., 3.1.13.4. and 3.2.2.16., a building or part of a building required to be of noncombustible construction, shall be constructed with noncombustible materials. (See also Subsection 3.1.13. for the requirements regarding the flame-spread…). Sentence (2) also allows a material that passes the cone calorimeter test (ULC S135 at 50 kW/m²) with low heat release and smoke.
| Combustible item in noncombustible building | Condition |
|---|---|
| Pneumatic control tubing | max 10 mm outside diameter (3.1.5.2.OBC Div. B 3.1.5.2. Minor Combustible Components(1) The following minor combustible components are permitted in a building required to be of noncombustible construction: (a) paint, (See also Clause 3.1.13.1.(2)(b)) (b) self-adhesive tapes, mastics and caulking materials including foamed plastic air sealants, applied to provide a seal between the major components of…) |
| Exposed combustible piping | flame-spread max 25; in a 3.2.6. building, smoke developed max 50 (3.1.5.19.OBC Div. B 3.1.5.19. Combustible Piping Materials(1) Except as permitted by Clause 3.1.5.2.(1)(d) and Article 3.1.5.25. and Sentences (2) and (3), combustible piping and tubing and associated adhesives are permitted to be used in a building required to be of noncombustible construction provided that, except when concealed in a wall or concrete floor slab, they (a)…) |
| Combustible sprinkler piping | within a sprinklered floor area |
| Wires and cables | FT4, or in raceways, masonry, concrete, 1 h service room (3.1.5.21.OBC Div. B 3.1.5.21. Wires and Cables(1) Except as permitted by Sentence (2) and Articles 3.1.5.22. and 3.1.5.25., optical fibre cables and electrical wires and cables with combustible insulation, jackets or sheathes are permitted in a building required to be of noncombustible construction, provided (a) the wires and cables exhibit a vertical char of not…) |
| Non-metallic raceways | max 175 mm outside diameter (3.1.5.23.OBC Div. B 3.1.5.23. Non-metallic Raceways(1) Except as required in Sentence (2), subject to the limits on the size of elements that penetrate fire separations when complying with Article 3.1.9.2., within a fire compartment of a building required to be of noncombustible construction, totally enclosed non-metallic raceways not more than 175 mm in outside…) |
| Elevator travelling cables | permitted (3.1.5.22.OBC Div. B 3.1.5.22. Combustible Travelling Cables for Elevators(1) Combustible travelling cables are permitted on elevating devices in a building required to be of noncombustible construction.) |
| Cables under a computer room raised floor | FT1, or FT4/FT6 (3.1.5.25.OBC Div. B 3.1.5.25. Wires in Computer Room Floors(1) Optical fibre cables and electrical wires and cables with combustible insulation, jackets or sheathes, located in the space below a raised floor in a computer room, are permitted in a building required to be of noncombustible construction provided they do not convey flame or continue to burn for more than 1 min…) |
| Solar collector system above the roof | permitted (3.1.5.28.OBC Div. B 3.1.5.28. Combustible Solar Collector Systems(1) A combustible solar collector system is permitted to be installed above the roof of a building required to be of noncombustible construction.) |
Other minor combustible components in 3.1.5.2. include paint, sealants between exterior wall components, firestops and fire blocks, adhesives and vapour barriers, outlet boxes, and wood blocking for windows and for wall-mounted items.
Common traps: thinking combustible sprinkler pipe is allowed anywhere (only in sprinklered floor areas); forgetting the extra smoke limit for high buildings; confusing the FT1, FT4 and FT6 ratings (FT6 is the plenum rating).
Occupant load
Occupant load is based on fixed seats in assembly spaces, 2 persons per sleeping room in a dwelling unit, or otherwise the design number but not less than the Table 3.1.17.1.OBC Div. B Table 3.1.17.1. Occupant LoadTable 3.1.17.1. Occupant Load Forming Part of Article 3.1.17.1. Type of Use of Floor Area or Part Thereof | Area per Person, m[2] Assembly uses | N/A space with fixed seats | [1] space with non-fixed seats | 0.75 stages for theatrical performances | 0.75 space with non-fixed seats and tables | 0.95 standing space |… value unless fewer can be shown (OBC Div. B 3.1.17.1.OBC Div. B 3.1.17.1. Occupant Load Determination(1) The occupant load of a floor area or part of a floor area, shall be based on (a) the number of seats in an assembly occupancy having fixed seats, (b) 2 persons per sleeping room in a dwelling unit, or (c) the number of persons for which the area is designed, but not less than that determined from Table 3.1.17.1…). A design load different from the table must be posted on a permanent sign. Mezzanines, tiers and balconies count as part of the floor area. A room used for different occupancies at different times uses the factor giving the most people.
A selection of factors (m² per person):
| Use | m²/person |
|---|---|
| Standing space | 0.40 |
| Non-fixed seats | 0.75 |
| Dining, beverage, cafeteria | 1.20 |
| Classrooms | 1.85 |
| Mercantile first storey | 3.70 |
| Mercantile other storeys | 5.60 |
| Offices | 9.30 |
| Warehouse storage | 28.00 |
Chapter review
Chapter at a glance
One line per section: the idea to carry into the exam. Then the answers that most often catch candidates out.
- Classification of buildings by major occupancy
Each building or part is classified by major occupancy into the Groups and Divisions of, and a building with several major occupancies is classified by all of them.
- Separation of major occupancies and prohibited combinations
Sentence (2) lowers the C to E separation to 1 h in a building not more than 3 storeys with not more than two dwelling units.
- Combustible and noncombustible materials
A building permitted to be of combustible construction may use combustible materials, with or without noncombustible components.
- Occupant load
Occupant load is based on fixed seats in assembly spaces, 2 persons per sleeping room in a dwelling unit, or otherwise the design number but not less than the value unless fewer…
Practice this chapter
Questions on Classification, occupancy separations, materials and occupant load, in the exam format, every answer explained and cited to its article. Sign in to start; a free account gets the free questions.
Code cited in this chapter
Based on the official 2024 Building Code Compendium on ontario.ca.
© King's Printer for Ontario, 2024. Reproduced with permission.
OBC Div. B Table 3.1.2.1. Major Occupancy Classification
Open OBC Div. B Table 3.1.2.1. in the code viewerTable 3.1.2.1. Major Occupancy Classification Forming Part of Sentences 3.1.2.1.(1), 3.1.2.2.(1) and 3.11.2.1.(3) Group | Division | Description of Major Occupancy A | 1 | Assembly occupancies intended for the production and viewing of the performing arts A | 2 | Assembly occupancies not elsewhere classified in Group A A | 3 | Assembly occupancies of the arena type A | 4 | Assembly occupancies in which occupants are gathered in the open air B | 1 | Detention occupancies B | 2 | Care and treatment occupancies B | 3 | Care occupancies C | N/A | Residential occupancies D | N/A | Business and personal services occupancies E | N/A | Mercantile occupancies F | 1 | High-hazard industrial occupancies F | 2 | Medium-hazard industrial occupancies F | 3 | Low-hazard industrial occupancies
OBC Div. B 3.1.2.1. Classification of Buildings
Open OBC Div. B 3.1.2.1. in the code viewer(1)Except as permitted by Articles 3.1.2.3. to 3.1.2.7., every building or part thereof shall be classified according to its major occupancy as belonging to one of the Groups or Divisions described in Table 3.1.2.1. (See Note A-3.1.2.1.(1))
(2)A building intended for use by more than one major occupancy shall be classified according to all major occupancies for which it is used or intended to be used.
OBC Div. B 3.1.2.2. Occupancies of the Same Classification
Open OBC Div. B 3.1.2.2. in the code viewer(1)Any building is deemed to be occupied by a single major occupancy, notwithstanding its use for more than one major occupancy, provided that all occupancies are classified as belonging to the same Group classification or, where the Group is divided into Divisions, as belonging to the same Division classification described in Table 3.1.2.1.
OBC Div. B 3.1.2.3. Arena-Type Buildings
Open OBC Div. B 3.1.2.3. in the code viewer(1)An arena-type building intended for occasional use for trade shows and similar exhibition purposes shall be classified as Group A, Division 3 occupancy.
OBC Div. B 3.1.2.4. Police Stations
Open OBC Div. B 3.1.2.4. in the code viewer(1)A police station with detention quarters is permitted to be classified as a Group B, Division 2 major occupancy provided the station is not more than 1 storey in building height and 600 m² in building area.
OBC Div. B 3.1.2.5. Group B, Division 3 Occupancies
Open OBC Div. B 3.1.2.5. in the code viewer(1)Group B, Division 3 occupancies are permitted to be classified as Group C major occupancies within the application of Part 3 provided
(a)the occupants live as a single housekeeping unit in a suite with sleeping accommodation for not more than 10 persons, and
(b)not more than two occupants require assistance in evacuation in case of an emergency.
OBC Div. B 3.1.2.6. Storage of Combustible Fibres
Open OBC Div. B 3.1.2.6. in the code viewer(1)Buildings or parts of thereof used for the storage of baled combustible fibres shall be classified as medium-hazard industrial occupancies.
OBC Div. B 3.1.2.7. Restaurants
Open OBC Div. B 3.1.2.7. in the code viewer(1)A restaurant is permitted to be classified as a Group E major occupancy within the application of Part 3 provided the restaurant is designed to accommodate not more than 30 persons consuming food or drink.
Show all 24 articles
OBC Div. B Table 3.1.3.1. Major Occupancy Fire Separations—Minimum Fire-Resistance Rating of Fire Separation, h[1]
Open OBC Div. B Table 3.1.3.1. in the code viewerTable 3.1.3.1. Major Occupancy Fire Separations—Minimum Fire-Resistance Rating of Fire Separation, h[1] Forming Part of Sentence 3.1.3.1.(1) Major Occupancy | Adjoining Major Occupancy A-1 | Adjoining Major Occupancy A-2 | Adjoining Major Occupancy A-3 | Adjoining Major Occupancy A-4 | Adjoining Major Occupancy B-1 | Adjoining Major Occupancy B-2 | Adjoining Major Occupancy B-3 | Adjoining Major Occupancy C | Adjoining Major Occupancy D | Adjoining Major Occupancy E | Adjoining Major Occupancy F-1 | Adjoining Major Occupancy F-2 | Adjoining Major Occupancy F-3 A-1 | N/A | 1 | 1 | 1 | 2 | 2 | 2 | 1 | 1 | 2 | [2] | 2 | 1 A-2 | 1 | N/A | 1 | 1 | 2 | 2 | 2 | 1[3] | 1[4] | 2 | [2] | 2 | 1 A-3 | 1 | 1 | N/A | 1 | 2 | 2 | 2 | 1 | 1 | 2 | [2] | 2 | 1 A-4 | 1 | 1 | 1 | N/A | 2 | 2 | 2 | 1 | 1 | 2 | [2] | 2 | 1 B-1 | 2 | 2 | 2 | 2 | N/A | 2 | 2 | 2 | 2 | 2 | [2] | 2 | 2 B-2 | 2 | 2 | 2 | 2 | 2 | N/A | 1 | 2 | 2 | 2 | [2] | 2 | 2 B-3 | 2 | 2 | 2 | 2 | 2 | 1 | N/A | 2 | 2 | 2 | [2] | 2 | 2 C | 1 | 1[3] | 1 | 1 | 2 | 2 | 2 | N/A | 1 | 2[5] | [2] | 2[6] | 1 D | 1 | 1[4] | 1 | 1 | 2 | 2 | 2 | 1 | N/A | N/A | 3 | N/A | N/A E | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2[5] | N/A | N/A | 3 | N/A | N/A F-1 | [2] | [2] | [2] | [2] | [2] | [2] | [2] | [2] | 3 | 3 | N/A | 2 | 2 F-2 | 2 | 2 | 2 | 2 | 2 | 2 | 2 | 2[6] | N/A | N/A | 2 | N/A | N/A F-3 | 1 | 1 | 1 | 1 | 2 | 2 | 2 | 1 | N/A | N/A | 2 | N/A | N/A Notes to Table 3.1.3.1.: (1) Section 3.3. contains requirements for the separation of occupancies and tenancies that are in addition to the requirements for the separation of major occupancies. (2) See Sentence 3.1.3.2.(1). (3) Where the building or part thereof is constructed in accordance with Article 3.2.2.51., a fire separation with a 2 h fire-resistance rating is required between the Group C and Group A, Division 2 major occupancies. (4) Where the building or part thereof is constructed in accordance with Article 3.2.2.60., a fire separation with a 2 h fire-resistance rating is required between the Group D and Group A, Division 2 major occupancies. (5) See Sentence 3.1.3.1.(2). (6) See Sentence 3.1.3.2.(2).
OBC Div. B 3.1.3.1. Separation of Major Occupancies
Open OBC Div. B 3.1.3.1. in the code viewer(1)Except as permitted by Sentences (2) and (3), 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 conforming to the requirements of Articles 3.2.8.2. to 3.2.8.8., the requirements of Sentence (1) for fire separations between major occupancies do not apply at the vertical plane around the perimeter of an opening through the horizontal fire separation.
OBC Div. B 3.1.3.2. Prohibition of Occupancy Combinations
Open OBC Div. B 3.1.3.2. in the code viewer(1)No major occupancy of Group F, Division 1 shall be contained within a building with any occupancy classified as Group A, B or C.
(2)Except as provided in Sentence (4) and Sentence 3.10.2.4.(9), not more than one suite of residential occupancy shall be contained within a building classified as a Group F, Division 2 major occupancy.
(3)A sleeping room or sleeping area shall not open directly into a room or area where food is intended to be stored, prepared, processed, distributed, served, sold or offered for sale. (See Note A-3.1.3.2.(3))
(4)A Group F, Division 2 major occupancy is permitted in a building containing only live/work units if the occupancy is for the exclusive use of the occupants of the live/work units.
(5)A building within the scope of Article 3.2.2.51. or 3.2.2.60. shall not contain a retirement home.
OBC Div. B 3.1.4.1. Combustible Materials Permitted
Open OBC Div. B 3.1.4.1. in the code viewer(1)A building permitted to be of combustible construction is permitted to be constructed of combustible materials, with or without noncombustible components. (See Note A-3.1.4.1.(1))
OBC Div. B 3.1.4.3. Wires and Cables
Open OBC Div. B 3.1.4.3. in the code viewer(1)Except as required by Sentence (2), optical fibre cables and electrical wires and cables with combustible insulation, jackets or sheathes installed in a building permitted to be of combustible construction shall
(a)not convey flame or continue to burn for more than 1 min when tested in conformance with the Vertical Flame Test (FT1 rating) in CSA C22.2 No. 0.3, "Test Methods for Electrical Wires and Cables," or
(b)be located in
(i)totally enclosed noncombustible raceways, (See Note A-3.1.4.3.(1)(b)(i))
(ii)masonry walls,
(iii)concrete slabs, or
(iv)totally enclosed non-metallic raceways conforming to Clause 3.1.5.23.(1)(b). (See Note A-3.1.4.3.(1)) (See also Sentence 3.6.4.3.(1))
(2)Except as permitted in Sentences (3) and (4), optical fibre cables and electrical wires and cables with combustible insulation, jackets or sheathes that are used for the transmission of voice, sound or data and are installed in a plenum in a building permitted to be of combustible construction shall exhibit the following characteristics when tested in conformance with CAN/ULC-S102.4, "Standard Method of Test for Fire and Smoke Characteristics of Electrical Wiring, Cables and Non-Metallic Raceways," (FT6 rating):
(a)a horizontal flame distance of not more than 1.5 m,
(b)an average optical smoke density of not more than 0.15, and
(c)a peak optical smoke density of not more than 0.5.
(3)Except as permitted in Sentence (4), where totally enclosed noncombustible raceways are used in a plenum, exposed components of wiring systems with combustible insulation, jackets or sheathes, including optical fibre cables and electrical wires and cables that are used for the transmission of voice, sound or data, that are installed in the plenum or that extend not more than 9 m from the plenum, including drop down to the floor level, are permitted, provided they exhibit a vertical char of not more than 1.5 m when tested in conformance with the Vertical Flame Test-Cables in Cable Trays (FT4 rating) in CSA C22.2 No. 0.3, "Test Methods for Electrical Wires and Cables."
(4)Cables or wires within plenums that are used for the transmission of signals in fire alarm systems need not comply with the requirements of Sentence (2).
OBC Div. B 3.1.4.4. Non-metallic Raceways
Open OBC Div. B 3.1.4.4. in the code viewer(1)Totally enclosed non-metallic raceways used in a plenum in a building permitted to be of combustible construction shall meet the requirements of Clause 3.1.5.23.(1)(a).
OBC Div. B 3.1.5.1. Noncombustible Materials)
Open OBC Div. B 3.1.5.1. in the code viewer(1)Except as permitted by Sentences (2) to (4) and Articles 3.1.5.2. to 3.1.5.29., 3.1.13.4. and 3.2.2.16., a building or part of a building required to be of noncombustible construction, shall be constructed with noncombustible materials. (See also Subsection 3.1.13. for the requirements regarding the flame-spread rating of interior finishes.)
(2)Notwithstanding the definition of noncombustible materials stated in Article 1.4.1.2. of Division A, a material is permitted to be used in noncombustible construction provided that, when tested in accordance with ULC S135, "Standard Test Method for the Determination of Combustibility Parameters of Building Materials Using an Oxygen Consumption Calorimeter (Cone Calorimeter)", at a heat flux of 50 kW/m²,
(a)its average total heat release is not more than 3 MJ/m²,
(b)its average total smoke extinction area is not more than 1.0 m², and
(c)the test duration is extended beyond the time stipulated in the referenced standard until it is clear that there is no further release of heat or smoke.
(3)If a material referred to in Sentence (2) consists of a number of discrete layers and testing reveals that the surface layer or layers protect the underlying layers such that complete combustion of the underlying layers does not occur, the test shall be repeated by removing the outer layers sequentially until all layers have been exposed during testing, or until complete combustion has occurred.
(4)The acceptance criteria for a material tested in accordance with Sentence (3) shall be based on the cumulative emissions from all layers, which must not exceed the criteria stated in Clauses (2)(a) and (b).
OBC Div. B 3.1.5.2. Minor Combustible Components
Open OBC Div. B 3.1.5.2. in the code viewer(1)The following minor combustible components are permitted in a building required to be of noncombustible construction:
(a)paint, (See also Clause 3.1.13.1.(2)(b))
(b)self-adhesive tapes, mastics and caulking materials including foamed plastic air sealants, applied to provide a seal between the major components of exterior wall construction, (See also Article 3.6.4.3. for limits on the use of combustible materials in plenum spaces),
(c)firestops and fire blocks conforming to Sentence 3.1.9.1.(1) Article 3.1.11.7.,
(d)tubing for pneumatic controls provided it has an outside diameter not more than 10 mm,
(e)adhesives, vapour barriers and sheathing papers,
(f)electrical outlet and junction boxes,
(g)wood blocking intended for the attachment of window elements within exterior wall assemblies,
(h)wood blocking within wall assemblies intended for the attachment of handrails, fixtures, and similar items mounted on the surface of the wall, and
(i)similar minor components.
OBC Div. B 3.1.5.19. Combustible Piping Materials
Open OBC Div. B 3.1.5.19. in the code viewer(1)Except as permitted by Clause 3.1.5.2.(1)(d) and Article 3.1.5.25. and Sentences (2) and (3), combustible piping and tubing and associated adhesives are permitted to be used in a building required to be of noncombustible construction provided that, except when concealed in a wall or concrete floor slab, they
(a)have a flame-spread rating not more than 25, and
(b)if used in a building described in Subsection 3.2.6., have a smoke developed classification not more than 50.
(2)Combustible sprinkler piping is permitted to be used within a sprinklered floor area in a building required to be of noncombustible construction. (See also Article 3.2.5.13.)
(3)Polypropylene pipes and fittings are permitted to be used for drain, waste and vent piping for the conveyance of highly corrosive materials and for piping used to distribute distilled or dialyzed water in laboratory and hospital facilities in a building required to be of noncombustible construction, provided
(a)the building is sprinklered throughout,
(b)the piping is not located in a vertical shaft, and
(c)piping that penetrates a fire separation is sealed at the penetration by a firestop that has an FT rating not less than the fire-resistance rating of the fire separation when subjected to the fire test method in CAN/ULC-S115, "Standard Method of Fire Tests of Firestop Systems," with a pressure differential of 50 Pa between the exposed and unexposed sides, with the higher pressure on the exposed side.
OBC Div. B 3.1.5.21. Wires and Cables
Open OBC Div. B 3.1.5.21. in the code viewer(1)Except as permitted by Sentence (2) and Articles 3.1.5.22. and 3.1.5.25., optical fibre cables and electrical wires and cables with combustible insulation, jackets or sheathes are permitted in a building required to be of noncombustible construction, provided
(a)the wires and cables exhibit a vertical char of not more than 1.5 m when tested in conformance with the Vertical Flame Test-Cables in Cable Trays (FT4 rating) in CSA C22.2 No. 0.3, "Test methods for electrical wires and cables,"
(b)the wires and cables are located in
(i)totally enclosed noncombustible raceways, (See Note A-3.1.4.3.(1)(b)(i))
(ii)masonry walls.
(iii)concrete slabs,
(iv)a service room separated from the remainder of the building by a fire separation having a fire-resistance rating not less than 1 h, or
(v)totally enclosed non-metallic raceways conforming to Clause 3.1.5.23.(1)(b), or
(c)the wires and cables are communication cables used at the service entry to a building and are not more than 3 m long. (See Note A-3.1.5.21.(1))
(2)Except as permitted in Sentences (3) and (4), optical fibre cables and electrical wires and cables with combustible insulation, jackets or sheathes that are used for the transmission of voice, sound or data and are not located in totally enclosed noncombustible raceways are permitted to be installed in a plenum in a building required to be of noncombustible construction, provided the wires and cables exhibit a horizontal flame distance of not more than 1.5 m, an average optical smoke density of not more than 0.15, and a peak optical smoke density of not more than 0.5 when tested in conformance with CAN/ULC-S102.4, "Standard Method of Test for Fire and Smoke Characteristics of Electrical Wiring, Cables and Non-Metallic Raceways," (FT6 rating).
(3)Except as permitted in Sentence (4), where totally enclosed noncombustible raceways are used in a plenum, exposed components of wiring systems with combustible insulation, jackets or sheathes, including optical fibre cables and electrical wires and cables that are used for the transmission of voice, sound or data, that are installed in the plenum or that extend not more than 9 m from the plenum including drop down to the floor level, are permitted provided they exhibit a vertical char of not more than 1.5 m when tested in conformance with the Vertical Flame Test-Cables in Cable Trays (FT4 rating) in CSA C22.2 No. 0.3, "Test methods for electrical wires and cables."
(4)Cables or wires within plenums that are used for the transmission of signals in fire alarm systems need not comply with the requirements of Sentences (2) and (3).
OBC Div. B 3.1.5.23. Non-metallic Raceways
Open OBC Div. B 3.1.5.23. in the code viewer(1)Except as required in Sentence (2), subject to the limits on the size of elements that penetrate fire separations when complying with Article 3.1.9.2., within a fire compartment of a building required to be of noncombustible construction, totally enclosed non-metallic raceways not more than 175 mm in outside diameter, or of an equivalent rectangular area, are permitted to be used to enclose optical fibre cables and electrical wires and cables, provided
(a)where the wires and cables in the raceways meet or exceed the requirements of Clause 3.1.5.21.(1)(a), the non-metallic raceways meet the requirements for at least an FT4 rating in,
(i)CAN/CSA-C22.2 No. 262, "Optical Fiber Cable and Communication Cable Raceway Systems," or
(ii)CAN/ULC-S143, "Standard Method of Fire Tests for Non-Metallic Electrical and Optical Fibre Cable Raceway Systems," and
(b)where the wires and cables in the raceways do not meet or exceed the requirements of Clause 3.1.5.21.(1)(a), the non-metallic raceways exhibit a vertical char of not more than 1.5 m when tested in conformance with the Vertical Flame Test (FT4)-conduit or Tubing on Cable Tray in Clause 6.16 of CSA C22.2 No. 211.0, "General Requirements and Methods of Testing for Nonmetallic Conduit."
(2)Totally enclosed non-metallic raceways used in a plenum in a building required to be of noncombustible construction shall exhibit a horizontal flame distance of not more than 1.5 m, an average optical smoke density of not more than 0.15, and a peak optical smoke density of not more than 0.5 when tested in conformance with CAN/ULC-S102.4, "Standard Method of Test for Fire and Smoke Characteristics of Electrical Wiring, Cables and Non-Metallic Raceways," (FT6 rating).
OBC Div. B 3.1.5.22. Combustible Travelling Cables for Elevators
Open OBC Div. B 3.1.5.22. in the code viewer(1)Combustible travelling cables are permitted on elevating devices in a building required to be of noncombustible construction.
OBC Div. B 3.1.5.25. Wires in Computer Room Floors
Open OBC Div. B 3.1.5.25. in the code viewer(1)Optical fibre cables and electrical wires and cables with combustible insulation, jackets or sheathes, located in the space below a raised floor in a computer room, are permitted in a building required to be of noncombustible construction provided they do not convey flame or continue to burn for more than 1 min when tested in conformance with the Vertical Flame Test in Clause 4.11.1. of CSA C22.2 No. 0.3, "Test methods for electrical wires and cables," (FT1 Rating).
(2)The requirement in Sentence (1) is considered to be met where the wires and cables
(a)exhibit a vertical char of not more than 1.5 m when tested in conformance with the Vertical Flame Test-Cables in Cabletrough in Clause 4.11.4. of CSA C22.2 No. 0.3, "Test methods for electrical wires and cables," (FT4 Rating), or
(b)exhibit a flame-spread of not more than 1.5 m, a smoke density of not more than 0.5 at peak optical density and a smoke density not more than 0.15 at average optical density when tested in conformance with the Flame and Smoke Test in the Appendix to CSA C22.2 No. 0.3, "Test methods for electrical wires and cables," (FT6 Rating).
OBC Div. B 3.1.5.28. Combustible Solar Collector Systems
Open OBC Div. B 3.1.5.28. in the code viewer(1)A combustible solar collector system is permitted to be installed above the roof of a building required to be of noncombustible construction.
OBC Div. B Table 3.1.17.1. Occupant Load
Open OBC Div. B Table 3.1.17.1. in the code viewerTable 3.1.17.1. Occupant Load Forming Part of Article 3.1.17.1. Type of Use of Floor Area or Part Thereof | Area per Person, m[2] Assembly uses | N/A space with fixed seats | [1] space with non-fixed seats | 0.75 stages for theatrical performances | 0.75 space with non-fixed seats and tables | 0.95 standing space | 0.40 stadia and grandstands | 0.60 bowling alleys, pool and billiard rooms | 9.30 classrooms | 1.85 school shops and vocational rooms | 9.30 reading or writing rooms or lounges | 1.85 dining, beverage and cafeteria space | 1.20 laboratories in schools | 4.60 Care, care and treatment or detention uses | N/A B-1 : detention quarters | 11.60 B-2 : treatment and sleeping areas | 10.00 B-3 : sleeping room areas | 10.00 (See also Article 3.7.1.3.) | (See also Article 3.7.1.3.) Residential uses | N/A dwelling units | [2] dormitories | 4.60 Business and personal services uses | N/A personal service shops | 4.60 offices | 9.30 Mercantile uses | N/A basements and first storeys | 3.70 second storeys having a principal entrance from a pedestrian thoroughfare or a parking area | 3.70 other storeys | 5.60 Industrial uses | N/A manufacturing or process rooms | 4.60 storage garages | 46.00 storage spaces (warehouse) | 28.00 aircraft hangars | 46.00 Other uses | N/A cleaning and repair goods | 4.60 kitchens | 9.30 storage | 46.00 public corridors intended for occupancies in addition to pedestrian travel | 3.70[3] Notes to Table 3.1.17.1.: (1) See Clause 3.1.17.1.(1)(a). (2) See Clause 3.1.17.1.(1)(b) (3) See Note A-3.3.
OBC Div. B 3.1.17.1. Occupant Load Determination
Open OBC Div. B 3.1.17.1. in the code viewer(1)The occupant load of a floor area or part of a floor area, shall be based on
(a)the number of seats in an assembly occupancy having fixed seats,
(b)2 persons per sleeping room in a dwelling unit, or
(c)the number of persons for which the area is designed, but not less than that determined from Table 3.1.17.1. for occupancies other than those described in Clauses (a) and (b), unless it can be shown that the area will be occupied by fewer persons.
(2)If a floor area or part thereof it has been designed for an occupant load other than that determined from Table 3.1.17.1., a permanent sign indicating that occupant load shall be posted in a conspicuous location.
(3)For the purposes of this Article, mezzanines, tiers and balconies shall be regarded as part of the floor area.
(4)If a room or group of rooms is intended for different occupancies at different times, the value to be used from Table 3.1.17.1. shall be the value that gives the greatest number of persons for the occupancies concerned.