The Ontario Building Code | Classification of Buildings
3.1.2.1. Classification of buildings
(1) Except as provided by Articles 3.1.2.3. to 3.1.2.7., every building or part of it shall be classified according to its major occupancy as belonging to one of the Groups or Divisions described in Table 3.1.2.1.
(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.
Table 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)
| Item | Column 1 Group | Column 2 Division | Column 3 Description of Major Occupancies |
| 1. | A | 1 | Assembly occupancies intended for the production and viewing of the performing arts |
| 2. | A | 2 | Assembly occupancies not elsewhere classified in Group A |
| 3. | A | 3 | Assembly occupancies of the arena type |
| 4. | A | 4 | Assembly occupancies in which occupants are gathered in the open air |
| 5. | B | 1 | Detention occupancies |
| 6. | B | 2 | Care and treatment occupancies |
| 7. | B | 3 | Care occupancies |
| 8. | C | --- | Residential occupancies |
| 9. | D | --- | Business and personal services occupancies |
| 10. | E | --- | Mercantile occupancies |
| 11. | F | 1 | High hazard industrial occupancies |
| 12. | F | 2 | Medium hazard industrial occupancies |
| 13. | F | 3 | Low hazard industrial occupancies |
In Plain Language
This clause requires every building (or part of one) to be classified by its major occupancy type according to Table 3.1.2.1's Group/Division system (such as Group A for assembly, Group B for care/detention, and so on), and buildings with more than one major occupancy type must be classified under all the relevant categories that apply.
This is a plain-language summary of the 2012/2017 Ontario Building Code text above, for general understanding only and not a substitute for the Code. Always confirm current requirements against the 2024 edition (O.Reg. 163/24) or a qualified professional before construction.