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Values this chapter turns on
- maximum building area for Part 9 to apply
- 600 m²
- maximum building area for Part 9 to apply
- maximum annual average radon in designated areas
- 200 Bq/m³
- maximum annual average radon in designated areas
- roof slope at which Section 9.10 treats it as a wall
- 60°
- roof slope at which Section 9.10 treats it as a wall
- minimum thickness of soil as defined for Part 8
- 100 mm
- minimum thickness of soil as defined for Part 8
The Designer Legal/Process exam is mostly about the Act and Division C, but the syllabus also picks out a handful of Division A and B provisions that every designer should know: how referenced standards work, how farm buildings are classified, radon and flood plains, the window standard, two Part-specific definitions, the scope of Part 9, sloped roofs and residential suites in industrial buildings.
Each item is small, so questions here are usually direct lookups. Learn where each one lives.
Referenced documents (Division A 1.5.)
The Code adopts many standards by reference (CSA, ULC, ASTM and others). Division A 1.5. sets the ground rules:
| Rule | Plain meaning | Source |
|---|---|---|
| Scope of a referenced document | It applies only as far as it relates to buildings and to the objectives and functional statements of the acceptable solution that references it | OBC Div. A 1.5.1.1.OBC Div. A 1.5.1.1. Application of Referenced Documents(1) The provisions of documents referenced in this Code, and of any documents referenced within those documents, apply only to the extent that they relate to (a) buildings, and (b) the objectives and functional statements attributed to the applicable acceptable solutions in Division B where the documents are… |
| Conflict | If the Code and a referenced document conflict, the Code governs | OBC Div. A 1.5.1.2.OBC Div. A 1.5.1.2. Conflicting Requirements(1) In case of conflict between the provisions of this Code and those of a referenced document, the provisions of this Code shall govern. |
| Edition | Use the edition listed in Subsection 1.3.1. of Division B, not simply the newest | OBC Div. A 1.5.1.3.OBC Div. A 1.5.1.3. Applicable Editions(1) Where documents are referenced in this Code, they shall be the editions designated in Subsection 1.3.1. of Division B. |
| Abbreviations | Proper-name abbreviations (CSA, ULC and so on) have the meanings in Division B 1.3.2.1. | OBC Div. A 1.5.2.1.OBC Div. A 1.5.2.1. Abbreviations of Proper Names(1) The abbreviations of proper names in this Code shall have the meanings assigned to them in Article 1.3.2.1. of Division B. |
The edition rule catches people: a newer edition of a standard does not apply until the Code designates it.
Farm buildings (Division B 2.1.4.)
Every farm building, or part of one, is classified by major occupancy into one of the Group G divisions in Table 2.1.4.1. (OBC Div. B 2.1.4.1.OBC Div. B 2.1.4.1. Classification(1) Every farm building or part of a farm building shall be classified according to its major occupancy as belonging to one of the Divisions of Group G described in Table 2.1.4.1. (See Note A-2.1.4.1.(1)) (See also Note A-2.2.8.3.)):
| Division | Description |
|---|---|
| G-1 | High-hazard agricultural occupancies |
| G-2 | Agricultural occupancies not elsewhere classified |
| G-3 | Greenhouse agricultural occupancies |
| G-4 | Agricultural occupancies with no human occupants |
A "farm building" is a building or part of one that contains an agricultural occupancy (OBC Div. A 1.4.1.2.OBC Div. A 1.4.1.2.(1) Farm buildingFarm building means a building or part thereof that contains an agricultural occupancy. (See Note A-1.4.1.2.(1))). G-4 is an agricultural occupancy not intended to be occupied by people under normal use and generally used to store agricultural materials and by-products (OBC Div. A 1.4.1.2.OBC Div. A 1.4.1.2.(1) Agricultural occupancy with no human occupants (Group G, Division 4)Agricultural occupancy with no human occupants (Group G, Division 4) means an agricultural occupancy that is not intended to be occupied by persons under normal use and is generally used for the storage of agricultural materials and by-products. (See Note A-1.4.1.2.(1))).
Radon and flood plains (Division B 3.1.1.5., 3.1.1.6., 9.1.1.7., 9.1.1.8.)
Radon. In three designated areas, buildings must be designed and built so that the annual average radon 222 concentration inside does not exceed 200 Bq/m³ of air and its short lived daughters do not exceed 0.02 working levels (OBC Div. B 9.1.1.7.OBC Div. B 9.1.1.7. Radon(1) In addition to all other requirements, a building in the following designated areas shall be designed and constructed so that the annual average concentration of radon 222 does not exceed 200 Bq/m³ of air and the annual average concentration of the short lived daughters of radon 222 does not exceed 0.02 working…; the Part 3 version is 3.1.1.5.OBC Div. B 3.1.1.5. Radon(1) In addition to all other requirements, a building in the following designated areas shall be designed and constructed so that the annual average concentration of radon 222 does not exceed 200 Bq/m² of air and the annual average concentration of the short lived daughters of radon 222 does not exceed 0.02 working…). The areas are:
- the City of Elliot Lake (Territorial District of Algoma);
- the Township of Faraday (County of Hastings);
- the geographic Township of Hyman (Territorial District of Sudbury).
Flood plains. Buildings on flood plains must be designed and built using good engineering practice to withstand anticipated vertical and horizontal hydrostatic pressures, and must include floodproofing that keeps exits and means of egress intact during flooding (OBC Div. B 3.1.1.6.OBC Div. B 3.1.1.6. Building in Flood Plains(1) Buildings constructed on flood plains shall (a) be designed and constructed in accordance with good engineering practice to withstand anticipated vertical and horizontal hydrostatic pressures acting on the structure, and (b) incorporate floodproofing measures that will preserve the integrity of exits and means of… and 9.1.1.8.OBC Div. B 9.1.1.8. Building in Flood Plains(1) Buildings constructed on flood plains shall, (a) be designed and constructed in accordance with good engineering practice to withstand anticipated vertical and horizontal hydrostatic pressures acting on the structure, and (b) incorporate floodproofing measures that will preserve the integrity of exits and means of…). The Code gives no specific elevation here; that comes from other approvals.
Environmental separation standards (Division B 5.9.)
- Materials and components in environmental separators or assemblies exposed to the exterior, installed to meet Part 5, must meet the standards in Table 5.9.1.1. Flame-spread ratings in thermal insulation standards apply only as Part 3 requires (OBC Div. B 5.9.1.1.OBC Div. B 5.9.1.1. Compliance with Applicable Standards(1) Except as provided in Sentence (2) and elsewhere in this Part, materials and components, and their installation, shall conform to the requirements of the applicable standards in Table 5.9.1.1. where those materials or components are (a) incorporated into environmental separators or assemblies exposed to the…).
- Windows, doors and skylights must meet the North American Fenestration Standard (AAMA/WDMA/CSA 101/I.S.2/A440) and CSA A440S1, the Canadian Supplement. Performance grades are chosen under the Canadian Supplement for the conditions and location, and the product must meet them when tested to the Harmonized Standard (OBC Div. B 5.9.2.2.OBC Div. B 5.9.2.2. Applicable Standards(1) Windows, doors and skylights shall conform to the requirements in (a) AAMA/WDMA/CSA 101/I.S.2/A440, "North American Fenestration Standard/Specification for windows, doors, and skylights" (Harmonized Standard), and (b) CSA A440S1, "Canadian Supplement to AAMA/WDMA/CSA 101/I.S.2/A440-17, North American Fenestration…).
Plumbing and sewage system definitions
| Part | Term | Meaning | Source |
|---|---|---|---|
| 7 | Storey | The interval between two successive floor levels, including mezzanine floors that contain plumbing fixtures, or between a floor level and roof | OBC Div. B 7.1.1A.1.OBC Div. B 7.1.1A.1. Definitions(1) Except as provided in Sentence (2), words that appear in italics are defined in Article 1.4.1.2. of Division A and in the Building Code Act, 1992. (2) In this Part, Storey means the interval between two successive floor levels including mezzanine floors that contain plumbing fixtures or between a floor level and… |
| 8 | Soil | In-situ, naturally occurring, unconsolidated mineral or organic material at the surface, at least 100 mm thick and able to support plant growth; excludes displaced material like gravel dumps and mine spoils | OBC Div. B 8.1.1.2.OBC Div. B 8.1.1.2. Definitions(1) Except as provided in Sentence (2), words that appear in italics are defined in Article 1.4.1.2. of Division A and in the Building Code Act, 1992. (2) In this Part, Soil means in-situ, naturally occurring, unconsolidated mineral or organic material, at the earth's surface that is at least 100 mm thick and capable… |
All other italicized terms in Parts 7 and 8 take their meaning from Division A 1.4.1.2. and the Act.
Part 9 application, sloped roofs and residential suites
Part 9 scope. Division B 9.1.1.1. points to Division A 1.3.3. Part 9 applies to buildings of 3 storeys or less in building height, with a building area not exceeding 600 m², used for Group C (residential, other than retirement homes), Group D (business and personal services), Group E (mercantile), or Group F, Divisions 2 and 3 (medium and low hazard industrial) (OBC Div. A 1.3.3.3.OBC Div. A 1.3.3.3. Application of Part 9(1) Subject to Article 1.3.3.3B., Part 9 of Division B applies to all buildings described in Article 1.1.1.1. of 3 storeys or less in building height, having a building area not exceeding 600 m², and used for major occupancies classified as (a) reserved (b) Group C, residential occupancies other than buildings used…). Assembly, care, detention and high-hazard industrial buildings are always Part 3.
Section 9.1. also sends several building types to Part 3 rules even when small: signs (3.15.), self-service storage (3.10.), tents and air-supported structures (3.14.), food premises (3.7.6.), public pools and spas (3.11. and 3.12.), and shelf and rack storage (3.16.). Manufactured buildings are deemed to comply if built to CSA Z240.2.1 (sections not wider than 4.88 m) or CSA A277, but site work and site-built components must still meet the Code (OBC Div. B 9.1.1.9.OBC Div. B 9.1.1.9. Site Assembled and Factory-Built Buildings(1) Except as provided in Sentence (2) and in Sentence 12.2.1.2.(2), a manufactured building is deemed to comply with this Code if it is designed and constructed in compliance with, (a) CSA Z240.2.1, "Structural requirements for manufactured homes," if the building is constructed in sections not wider than 4.88 m, or…).
Sloped roofs. For Section 9.10., a roof sloped 60° or more from horizontal and next to a room or space intended for occupancy is treated as a wall (OBC Div. B 9.10.1.1.OBC Div. B 9.10.1.1. Sloped Roofs(1) For the purposes of this Section, roofs with slopes of 60° or more to the horizontal and that are adjacent to a room or space intended for occupancy shall be considered as a wall.).
Residential suites in industrial buildings. A building classified as Group F, Division 2 may contain not more than one suite of residential occupancy, with a related exception for live/work units (OBC Div. B 9.10.9.14.OBC Div. B 9.10.9.14. Residential Suites in Industrial Buildings(1) Except as provided in Sentence (2), not more than one suite of residential occupancy shall be contained within a building classified as a Group F, Division 2 major occupancy. (2) Except where a Group F Division 2 major occupancy is directly related to live/work units, not more than one suite of residential…).
Worked examples
Example 1. A 2-storey retail store of 520 m² building area: Part 9 (Group E, 3 storeys or less, not over 600 m²). The same store at 650 m²: Part 3.
Example 2. A designer specifies a window tested to an older edition of the fenestration standard than the one Division B 1.3.1. lists. Which edition governs? The edition designated in Division B 1.3.1. (Division A 1.5.1.3.).
Example 3. A site has 75 mm of natural topsoil over bedrock. Does that meet the Part 8 definition of soil? No, it must be at least 100 mm thick.
Common traps
- Assuming the newest edition of a standard applies.
- Applying Part 9 to a retirement home or a high-hazard industrial building.
- Mixing up G-3 (greenhouses) and G-4 (no human occupants).
- Treating imported gravel as "soil" for Part 8.
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.
- Referenced documents (Division A 1.5.)
The Code adopts many standards by reference (CSA, ULC, ASTM and others).
- Farm buildings (Division B 2.1.4.)
A "farm building" is a building or part of one that contains an agricultural occupancy.
- Plumbing and sewage system definitions
All other italicized terms in Parts 7 and 8 take their meaning from Division A 1.4.1.2. and the Act.
- Part 9 application, sloped roofs and residential suites
Section 9.1. also sends several building types to Part 3 rules even when small: signs (3.15.), self-service storage (3.10.), tents and air-supported structures (3.14.), food…
Usual exam traps
- Assuming the newest edition of a standard applies.
- Applying Part 9 to a retirement home or a high-hazard industrial building.
- Mixing up G-3 (greenhouses) and G-4 (no human occupants).
- Treating imported gravel as "soil" for Part 8.
Practice this chapter
Questions on Code structure and scope items from Divisions A and B, 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. A 1.5.1.1. Application of Referenced Documents
Open OBC Div. A 1.5.1.1. in the code viewer(1)The provisions of documents referenced in this Code, and of any documents referenced within those documents, apply only to the extent that they relate to
(a)buildings, and
(b)the objectives and functional statements attributed to the applicable acceptable solutions in Division B where the documents are referenced. (See Note A-1.5.1.1.(1))
OBC Div. A 1.5.1.2. Conflicting Requirements
Open OBC Div. A 1.5.1.2. in the code viewer(1)In case of conflict between the provisions of this Code and those of a referenced document, the provisions of this Code shall govern.
OBC Div. A 1.5.1.3. Applicable Editions
Open OBC Div. A 1.5.1.3. in the code viewer(1)Where documents are referenced in this Code, they shall be the editions designated in Subsection 1.3.1. of Division B.
OBC Div. A 1.5.2.1. Abbreviations of Proper Names
Open OBC Div. A 1.5.2.1. in the code viewer(1)The abbreviations of proper names in this Code shall have the meanings assigned to them in Article 1.3.2.1. of Division B.
OBC Div. B 2.1.4.1. Classification
Open OBC Div. B 2.1.4.1. in the code viewer(1)Every farm building or part of a farm building shall be classified according to its major occupancy as belonging to one of the Divisions of Group G described in Table 2.1.4.1. (See Note A-2.1.4.1.(1)) (See also Note A-2.2.8.3.)
OBC Div. A 1.4.1.2.(1) Farm building
Open OBC Div. A 1.4.1.2.(1) in the code viewerFarm building means a building or part thereof that contains an agricultural occupancy. (See Note A-1.4.1.2.(1))
OBC Div. A 1.4.1.2.(1) Agricultural occupancy with no human occupants (Group G, Division 4)
Open OBC Div. A 1.4.1.2.(1) in the code viewerAgricultural occupancy with no human occupants (Group G, Division 4) means an agricultural occupancy that is not intended to be occupied by persons under normal use and is generally used for the storage of agricultural materials and by-products. (See Note A-1.4.1.2.(1))
OBC Div. B 9.1.1.7. Radon
Open OBC Div. B 9.1.1.7. in the code viewer(1)In addition to all other requirements, a building in the following designated areas shall be designed and constructed so that the annual average concentration of radon 222 does not exceed 200 Bq/m³ of air and the annual average concentration of the short lived daughters of radon 222 does not exceed 0.02 working levels inside the building for,
(a)the City of Elliot Lake in the Territorial District of Algoma,
(b)the Township of Faraday in the County of Hastings, and
(c)the geographic Township of Hyman in the Territorial District of Sudbury.
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OBC Div. B 3.1.1.5. Radon
Open OBC Div. B 3.1.1.5. in the code viewer(1)In addition to all other requirements, a building in the following designated areas shall be designed and constructed so that the annual average concentration of radon 222 does not exceed 200 Bq/m² of air and the annual average concentration of the short lived daughters of radon 222 does not exceed 0.02 working levels inside the building:
(a)the City of Elliot Lake in the Territorial District of Algoma,
(b)the Township of Faraday in the County of Hastings, and
(c)the geographic Township of Hyman in the Territorial District of Sudbury.
OBC Div. B 3.1.1.6. Building in Flood Plains
Open OBC Div. B 3.1.1.6. in the code viewer(1)Buildings constructed on flood plains shall
(a)be designed and constructed in accordance with good engineering practice to withstand anticipated vertical and horizontal hydrostatic pressures acting on the structure, and
(b)incorporate floodproofing measures that will preserve the integrity of exits and means of egress during times of flooding.
OBC Div. B 9.1.1.8. Building in Flood Plains
Open OBC Div. B 9.1.1.8. in the code viewer(1)Buildings constructed on flood plains shall,
(a)be designed and constructed in accordance with good engineering practice to withstand anticipated vertical and horizontal hydrostatic pressures acting on the structure, and
(b)incorporate floodproofing measures that will preserve the integrity of exits and means of egress during times of flooding.
OBC Div. B 5.9.1.1. Compliance with Applicable Standards
Open OBC Div. B 5.9.1.1. in the code viewer(1)Except as provided in Sentence (2) and elsewhere in this Part, materials and components, and their installation, shall conform to the requirements of the applicable standards in Table 5.9.1.1. where those materials or components are
(a)incorporated into environmental separators or assemblies exposed to the exterior, and
(b)installed to fulfill the requirements of this Part. (See Note A-5.9.1.1.(1))
(2)The requirements for flame-spread ratings contained in thermal insulation standards shall be applied only as required in Part 3.
OBC Div. B 5.9.2.2. Applicable Standards
Open OBC Div. B 5.9.2.2. in the code viewer(1)Windows, doors and skylights shall conform to the requirements in
(a)AAMA/WDMA/CSA 101/I.S.2/A440, "North American Fenestration Standard/Specification for windows, doors, and skylights" (Harmonized Standard), and
(b)CSA A440S1, "Canadian Supplement to AAMA/WDMA/CSA 101/I.S.2/A440-17, North American Fenestration Standard/Specification for windows, doors, and skylights."
(2)Performance grades for windows, doors and skylights shall be selected according to the Canadian Supplement referenced in Clause (1)(b) so as to be appropriate for the conditions and geographic location in which the window, door or skylight will be installed.
(3)Windows, doors and skylights shall conform to the performance grades selected in Sentence (2) when tested in accordance with the Harmonized Standard referenced in Clause (1)(a).
OBC Div. B 7.1.1A.1. Definitions
Open OBC Div. B 7.1.1A.1. in the code viewer(1)Except as provided in Sentence (2), words that appear in italics are defined in Article 1.4.1.2. of Division A and in the Building Code Act, 1992.
(2)In this Part,
Storey means the interval between two successive floor levels including mezzanine floors that contain plumbing fixtures or between a floor level and roof.
OBC Div. B 8.1.1.2. Definitions
Open OBC Div. B 8.1.1.2. in the code viewer(1)Except as provided in Sentence (2), words that appear in italics are defined in Article 1.4.1.2. of Division A and in the Building Code Act, 1992.
(2)In this Part,
Soil means in-situ, naturally occurring, unconsolidated mineral or organic material, at the earth's surface that is at least 100 mm thick and capable of supporting plant growth, and includes material compacted or cemented by soil forming processes, but does not include displaced materials such as gravel dumps, mine spoils, or like deposits.
OBC Div. A 1.3.3.3. Application of Part 9
Open OBC Div. A 1.3.3.3. in the code viewer(1)Subject to Article 1.3.3.3B., Part 9 of Division B applies to all buildings described in Article 1.1.1.1. of 3 storeys or less in building height, having a building area not exceeding 600 m², and used for major occupancies classified as
(a)reserved
(b)Group C, residential occupancies other than buildings used for retirement homes, (See Note A-9.1.1.1.(1) of Division B)
(c)Group D, business and personal services occupancies,
(d)Group E, mercantile occupancies, or
(e)Group F, Divisions 2 and 3, medium- and low-hazard industrial occupancies.
OBC Div. B 9.1.1.9. Site Assembled and Factory-Built Buildings
Open OBC Div. B 9.1.1.9. in the code viewer(1)Except as provided in Sentence (2) and in Sentence 12.2.1.2.(2), a manufactured building is deemed to comply with this Code if it is designed and constructed in compliance with,
(a)CSA Z240.2.1, "Structural requirements for manufactured homes," if the building is constructed in sections not wider than 4.88 m, or
(b)CSA A277, "Procedure for certification of prefabricated buildings, modules, and panels."
(2)The requirements of this Code shall apply to,
(a)building components designed and constructed outside the place of manufacture, and
(b)site installation of such buildings.
OBC Div. B 9.10.1.1. Sloped Roofs
Open OBC Div. B 9.10.1.1. in the code viewer(1)For the purposes of this Section, roofs with slopes of 60° or more to the horizontal and that are adjacent to a room or space intended for occupancy shall be considered as a wall.
OBC Div. B 9.10.9.14. Residential Suites in Industrial Buildings
Open OBC Div. B 9.10.9.14. in the code viewer(1)Except as provided in Sentence (2), not more than one suite of residential occupancy shall be contained within a building classified as a Group F, Division 2 major occupancy.
(2)Except where a Group F Division 2 major occupancy is directly related to live/work units, not more than one suite of residential occupancy shall be contained within a building classified as Group F, Division 2 major occupancy.