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Values this chapter turns on
- retaining wall height that makes it a structure
- 1,000 mm
- retaining wall height that makes it a structure
- roof height that triggers window cleaning anchors
- 8 m
- roof height that triggers window cleaning anchors
- inset from floor edge that allows tempered glass
- 150 mm
- inset from floor edge that allows tempered glass
- max thickness of tempered glass in a guard
- 6 mm
- max thickness of tempered glass in a guard
Sections 4.3 and 4.4 are short. They send member design out to CSA and other standards, and they add a few special structures. The exam cannot ask what those standards say, because they are not in the Compendium. It can, and does, ask which standard the Code names for a material, plus the few conditions written into the OBC text itself.
Design standards by material (4.3)
Each structural material has one governing standard:
| Material | Standard the Code names | Article |
|---|---|---|
| Wood | CSA O86, "Engineering design in wood" | 4.3.1.1.OBC Div. B 4.3.1.1. Design Basis for Wood(1) Buildings and their structural members made of wood shall conform to CSA O86, "Engineering design in wood." |
| Glued-laminated members (fabrication plants) | CSA O177 | 4.3.1.2.OBC Div. B 4.3.1.2. Glue-Laminated Members(1) Glued-laminated members shall be fabricated in plants conforming to CSA O177, "Qualification Code for Manufacturers of Structural Glued-Laminated Timber." |
| Plain and reinforced masonry | CSA S304, "Design of masonry structures" | 4.3.2.1.OBC Div. B 4.3.2.1. Design Basis for Plain and Reinforced Masonry(1) Buildings and their structural members made of plain and reinforced masonry shall conform to CSA S304, "Design of masonry structures." |
| Plain, reinforced and pre-stressed concrete | CSA A23.3, "Design of concrete structures" | 4.3.3.1.OBC Div. B 4.3.3.1. Design Basis for Plain, Reinforced and Pre-stressed Concrete(1) Buildings and their structural members made of plain, reinforced and pre-stressed concrete shall conform to CSA A23.3, "Design of concrete structures." (See Note A-4.3.3.1.(1)) |
| Structural steel | CSA S16, "Design of steel structures" | 4.3.4.1.OBC Div. B 4.3.4.1. Design Basis for Structural Steel(1) Buildings and their structural members made of structural steel shall conform to CSA S16, "Design of steel structures." (See Note A-4.3.4.1.(1)) |
| Cold-formed steel | CSA S136 (North American Specification) | 4.3.4.2.OBC Div. B 4.3.4.2. Design Basis for Cold-Formed Steel(1) Buildings and their structural members made of cold-formed steel shall conform to CSA S136, "North American Specification for the Design of Cold-Formed Steel Structural Members (using the Appendix B provisions applicable to Canada)." (See Note A-4.3.4.2.(1)) |
| Steel building systems (manufacturer certification) | CSA A660 | 4.3.4.3.OBC Div. B 4.3.4.3. Steel Building Systems(1) Steel building systems shall be manufactured by companies certified in accordance with the requirements of CSA A660, "Certification of manufacturers of steel building systems." |
| Aluminum | CSA S157/S157.1, with Section 4.1 loads | 4.3.5.1.OBC Div. B 4.3.5.1. Design Basis for Aluminum(1) Buildings and their structural members made of aluminum shall conform to CSA S157/S157.1, "Strength design in aluminum/Commentary on CSA S157-17, Strength design in aluminum," using the loads stipulated in Section 4.1., in accordance with limit states design in Subsection 4.1.3. |
Common traps:
- CSA A23.1 against A23.3. A23.1 covers concrete materials and construction methods, and is cited for chemical attack in 4.2.3.6. A23.3 is the concrete design standard.
- CSA O80 against O86. O80 is wood preservation (4.2.3.2). O86 is wood design.
- Termites. Where an area is known to be infested by termites, 4.3.1.3 sends a Part 4 wood building to three Part 9 articles: 9.3.2.9, 9.12.1.1 and 9.15.5.1 OBC Div. B 4.3.1.3.OBC Div. B 4.3.1.3. Termites(1) In areas known to be infested by termites, the requirements in Articles 9.3.2.9., 9.12.1.1. and 9.15.5.1. shall apply..
Glass may be designed in one of two ways OBC Div. B 4.3.6.1.OBC Div. B 4.3.6.1. Design Basis for Glass(1) Glass used in buildings shall be designed in conformance with (a) CAN/CGSB-12.20-M, "Structural Design of Glass for Buildings," using an adjustment factor on the wind load, W, of not less than 0.75, or (b) ASTM E1300, "Standard Practice for Determining Load Resistance of Glass in Buildings," using an adjustment…:
- To CAN/CGSB-12.20-M, using an adjustment factor on the wind load W of not less than 0.75.
- To ASTM E1300, using an adjustment factor of not less than 1.0.
Exam writers like to swap these two numbers.
Special structures (4.4)
Each special structure type has its own rule:
| Structure | Requirement | Article |
|---|---|---|
| Air-supported, cable-supported and frame-supported membrane structures | CSA S367, with Section 4.1 loads and limit states design | 4.4.1.1.OBC Div. B 4.4.1.1. Design Basis for Air-, Cable- and Frame-Supported Membrane Structures(1) The structural design of air-supported structures or cable- and frame-supported membrane structures shall conform to CSA S367, "Air-, cable-, and frame-supported membrane structures" using the loads stipulated in Section 4.1., in accordance with limit states design in Subsection 4.1.3. |
| Storage garages and repair garages, including ramps and pedestrian areas | the performance requirements of CSA S413, "Parking structures" | 4.4.2.1.OBC Div. B 4.4.2.1. Design Basis for Storage Garages and Repair Garages(1) Storage garages and repair garages, including associated ramps and pedestrian areas, shall be designed in conformance with the performance requirements of CSA S413, "Parking structures." (See Note A-4.4.2.1.(1)) |
| Storage racks, including their anchorage | designed for the loads in Part 4 | 4.4.3.1.OBC Div. B 4.4.3.1. Design Basis for Storage Racks(1) Storage racks, including anchorage of racks, shall be designed for loads in accordance with this Part. (See Note A-4.1.8.18.(13) and 4.4.3.1.(1).) |
Two of these are often missed on the exam. Storage racks are not treated as furniture, so their anchorage is part of the design. Parking structures follow S413 "performance requirements", not just a load table.
Guards over retaining walls
Some retaining walls count as buildings. Division A designates a retaining wall more than 1,000 mm in exposed height as a structure under the Act when it is next to any of these OBC Div. A 1.3.3.5.OBC Div. A 1.3.3.5. Designated Structures(1) The following structures are designated for the purposes of clause (d) of the definition of building in subsection 1 (1) of the Act: (a) a retaining wall exceeding 1,000 mm in exposed height adjacent to (i) public property, (ii) access to a building, or (iii) private property to which the public is admitted, (b) a…:
- public property;
- access to a building;
- private property to which the public is admitted.
Part 4 applies to such walls OBC Div. A 1.3.3.2.OBC Div. A 1.3.3.2. Application of Parts 3, 4, 5 and 6(1) Subject to Articles 1.3.3.1A., 1.3.3.3B., Parts 3, 4, 5, and 6 of Division B apply to all buildings described in Article 1.1.1.1. and (a) classified as post-disaster buildings, (b) used for major occupancies classified as (i) Group A, assembly occupancies, (ii) Group B, care, care and treatment or detention….
Where the public has access to the open space at the top of such a wall, guards are required on all open sides OBC Div. B 4.4.4.1.OBC Div. B 4.4.4.1. Guards Over Retaining Walls(1) Every retaining wall that is designated in Sentence 1.3.1.1.(1) of Division A shall be protected by guards on all open sides where the public has access to open space at the top of the retaining wall.. The guard itself is designed for the loads in 4.1.5.14.
Anchor systems for window cleaning
Some buildings will have suspended maintenance or window cleaning on the exterior. These need anchor systems wherever any part of the roof is more than 8 m above the adjacent ground OBC Div. B 4.4.5.1.OBC Div. B 4.4.5.1. Anchor Systems on Building Exterior(1) Where suspended maintenance and window cleaning operations are intended to be carried out on the exterior of a building described in Article 1.1.2.2. of Division A, anchor systems shall be provided where any portion of the roof is more than 8 m above adjacent ground level. (2) Except as provided in Sentence (3)…. The rules for the anchors:
- They are designed, installed and tested to CSA Z271.
- Other systems are allowed if they give an equal level of safety.
- The material must be one of three: stainless steel, another corrosion-resistant base material, or steel hot-dip galvanized to CSA G164.
Glass in guards (SB-13)
Some guards in Part 3 buildings use glass. Supplementary Standard SB-13 covers the glass in those guards. It does not cover walls that act as guards SB-13 1.1.1.1.OBC SB-13 1.1.1.1. Application(1) Except as provided in Sentence (2), this Supplementary Standard applies to glass used in interior and exterior guards in buildings described in Sentence 1.3.3.2.(1) of Division A of the Building Code. (2) This Supplementary Standard does not apply to glass used in (a) guards at locations referred to in Sentence….
Only safety glass may be used SB-13 2.1.1.1.OBC SB-13 2.1.1.1. Safety Glass(1) Glass other than safety glass shall not be used in a guard. (2) Glass in a guard shall conform to Table 2.1.1.1.. The permitted glass type depends on how far the glass sits from the floor edge SB-13 Table 2.1.1.1.OBC SB-13 Table 2.1.1.1. Selection of Glass in a Guard — Forming Part of Sentence 2.1.1.1.(2)Table 2.1.1.1. — Selection of Glass in a Guard — Forming Part of Sentence 2.1.1.1.(2) Location of Glass in a Guard | Type of Glass Required Glass located beyond the edge of a floor or within 50 mm of the edge of a floor | Heat strengthened laminated glass Glass located more than 50 mm inward from the edge of a floor |…:
| Glass location | Glass permitted |
|---|---|
| Beyond the floor edge or within 50 mm of it | heat-strengthened laminated glass |
| More than 50 mm in | also heat-soaked tempered glass |
| More than 150 mm in | also tempered glass not more than 6 mm thick |
The glass is designed to Part 4. It must not touch metal or other hard elements of the guard, and it needs room for deflection and for thermal movement SB-13 3.1.1.1.OBC SB-13 3.1.1.1. Structural Design(1) Glass in a guard shall conform to the requirements of Part 4 of Division B of the Building Code. (See Appendix A.) (2) Glass in a guard shall not be in direct contact with any metal or similar hard elements forming part of the guard or supporting structure. (3) Sufficient allowances shall be incorporated for glass….
What you cannot be tested on
You will not be asked to size a member, check a connection or find a resistance factor. Those come from O86, S304, A23.3 and S16, which are outside the Compendium. If a question seems to need one of those standards, look again: it is probably asking which standard applies.
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.
- Design standards by material (4.3)
Exam writers like to swap these two numbers.
- Special structures (4.4)
Two of these are often missed on the exam.
- Glass in guards (SB-13)
Some guards in Part 3 buildings use glass.
- What you cannot be tested on
You will not be asked to size a member, check a connection or find a resistance factor.
Practice this chapter
Questions on Structural materials and special structures (4.3, 4.4), 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 4.3.1.1. Design Basis for Wood
Open OBC Div. B 4.3.1.1. in the code viewer(1)Buildings and their structural members made of wood shall conform to CSA O86, "Engineering design in wood."
OBC Div. B 4.3.1.2. Glue-Laminated Members
Open OBC Div. B 4.3.1.2. in the code viewer(1)Glued-laminated members shall be fabricated in plants conforming to CSA O177, "Qualification Code for Manufacturers of Structural Glued-Laminated Timber."
OBC Div. B 4.3.2.1. Design Basis for Plain and Reinforced Masonry
Open OBC Div. B 4.3.2.1. in the code viewer(1)Buildings and their structural members made of plain and reinforced masonry shall conform to CSA S304, "Design of masonry structures."
OBC Div. B 4.3.3.1. Design Basis for Plain, Reinforced and Pre-stressed Concrete
Open OBC Div. B 4.3.3.1. in the code viewer(1)Buildings and their structural members made of plain, reinforced and pre-stressed concrete shall conform to CSA A23.3, "Design of concrete structures." (See Note A-4.3.3.1.(1))
OBC Div. B 4.3.4.1. Design Basis for Structural Steel
Open OBC Div. B 4.3.4.1. in the code viewer(1)Buildings and their structural members made of structural steel shall conform to CSA S16, "Design of steel structures." (See Note A-4.3.4.1.(1))
OBC Div. B 4.3.4.2. Design Basis for Cold-Formed Steel
Open OBC Div. B 4.3.4.2. in the code viewer(1)Buildings and their structural members made of cold-formed steel shall conform to CSA S136, "North American Specification for the Design of Cold-Formed Steel Structural Members (using the Appendix B provisions applicable to Canada)." (See Note A-4.3.4.2.(1))
OBC Div. B 4.3.4.3. Steel Building Systems
Open OBC Div. B 4.3.4.3. in the code viewer(1)Steel building systems shall be manufactured by companies certified in accordance with the requirements of CSA A660, "Certification of manufacturers of steel building systems."
OBC Div. B 4.3.5.1. Design Basis for Aluminum
Open OBC Div. B 4.3.5.1. in the code viewer(1)Buildings and their structural members made of aluminum shall conform to CSA S157/S157.1, "Strength design in aluminum/Commentary on CSA S157-17, Strength design in aluminum," using the loads stipulated in Section 4.1., in accordance with limit states design in Subsection 4.1.3.
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OBC Div. B 4.3.1.3. Termites
Open OBC Div. B 4.3.1.3. in the code viewer(1)In areas known to be infested by termites, the requirements in Articles 9.3.2.9., 9.12.1.1. and 9.15.5.1. shall apply.
OBC Div. B 4.3.6.1. Design Basis for Glass
Open OBC Div. B 4.3.6.1. in the code viewer(1)Glass used in buildings shall be designed in conformance with
(a)CAN/CGSB-12.20-M, "Structural Design of Glass for Buildings," using an adjustment factor on the wind load, W, of not less than 0.75, or
(b)ASTM E1300, "Standard Practice for Determining Load Resistance of Glass in Buildings," using an adjustment factor on the wind load, W, of not less than 1.0.
(See Note A-4.3.6.1.(1))
OBC Div. B 4.4.1.1. Design Basis for Air-, Cable- and Frame-Supported Membrane Structures
Open OBC Div. B 4.4.1.1. in the code viewer(1)The structural design of air-supported structures or cable- and frame-supported membrane structures shall conform to CSA S367, "Air-, cable-, and frame-supported membrane structures" using the loads stipulated in Section 4.1., in accordance with limit states design in Subsection 4.1.3.
OBC Div. B 4.4.2.1. Design Basis for Storage Garages and Repair Garages
Open OBC Div. B 4.4.2.1. in the code viewer(1)Storage garages and repair garages, including associated ramps and pedestrian areas, shall be designed in conformance with the performance requirements of CSA S413, "Parking structures." (See Note A-4.4.2.1.(1))
OBC Div. B 4.4.3.1. Design Basis for Storage Racks
Open OBC Div. B 4.4.3.1. in the code viewer(1)Storage racks, including anchorage of racks, shall be designed for loads in accordance with this Part. (See Note A-4.1.8.18.(13) and 4.4.3.1.(1).)
OBC Div. A 1.3.3.5. Designated Structures
Open OBC Div. A 1.3.3.5. in the code viewer(1)The following structures are designated for the purposes of clause (d) of the definition of building in subsection 1 (1) of the Act:
(a)a retaining wall exceeding 1,000 mm in exposed height adjacent to
(i)public property,
(ii)access to a building, or
(iii)private property to which the public is admitted,
(b)a pedestrian bridge appurtenant to a building,
(c)a crane runway,
(d)an exterior storage tank and its supporting structure that is not regulated by the Technical Standards and Safety Act, 2000,
(e)signs regulated by Section 3.15. of Division B that are not structurally supported by a building,
(f)a solar collector that is mounted on a building and has a face area equal to or greater than 5 m²,
(g)a structure that supports a wind turbine generator having a rated output of more than 3 kW,
(h)a dish antenna that is mounted on a building and has a face area equal to or greater than 5 m²,
(i)an outdoor pool,
(j)an outdoor public spa,
(k)a permanent solid nutrient storage facility with supporting walls exceeding 1,000 mm in exposed height,
(l)a demountable stage, and
(m)a demountable support structure.
OBC Div. A 1.3.3.2. Application of Parts 3, 4, 5 and 6
Open OBC Div. A 1.3.3.2. in the code viewer(1)Subject to Articles 1.3.3.1A., 1.3.3.3B., Parts 3, 4, 5, and 6 of Division B apply to all buildings described in Article 1.1.1.1. and
(a)classified as post-disaster buildings,
(b)used for major occupancies classified as
(i)Group A, assembly occupancies,
(ii)Group B, care, care and treatment or detention occupancies, or
(iii)Group F, Division 1, high-hazard industrial occupancies, or
(c)exceeding 600 m² in building area or exceeding 3 storeys in building height used for major occupancies classified as
(i)Group C, residential occupancies,
(ii)Group D, business and personal services occupancies,
(iii)Group E, mercantile occupancies, or
(iv)Group F, Divisions 2 and 3, medium- and low-hazard industrial occupancies.
(2)Subject to Articles 1.3.3.1A. and 1.3.3.3B., Part 4 of Division B applies to
(a)a retaining wall exceeding 1,000 mm in exposed height adjacent to
(i)public property,
(ii)access to a building, or
(iii)private property to which the public is admitted,
(b)a pedestrian bridge appurtenant to a building,
(c)a crane runway,
(d)an exterior storage tank and its supporting structure that is not regulated by the Technical Standards and Safety Act, 2000,
(e)signs regulated by Section 3.15. of Division B that are not structurally supported by a building,
(f)a structure that supports a wind turbine generator having a rated output of more than 3 kW,
(g)an outdoor pool that has a water depth greater than 3.5 m at any point, and
(h)a permanent solid nutrient storage facility with supporting walls exceeding 1,000 mm in exposed height.
(3)Section 3.11. of Division B applies to public pools.
(4)Section 3.12. of Division B applies to public spas.
(5)Section 3.15. of Division B applies to signs.
(6)Section 3.17. of Division B applies to demountable stages and demountable support structures.
OBC Div. B 4.4.4.1. Guards Over Retaining Walls
Open OBC Div. B 4.4.4.1. in the code viewer(1)Every retaining wall that is designated in Sentence 1.3.1.1.(1) of Division A shall be protected by guards on all open sides where the public has access to open space at the top of the retaining wall.
OBC Div. B 4.4.5.1. Anchor Systems on Building Exterior
Open OBC Div. B 4.4.5.1. in the code viewer(1)Where suspended maintenance and window cleaning operations are intended to be carried out on the exterior of a building described in Article 1.1.2.2. of Division A, anchor systems shall be provided where any portion of the roof is more than 8 m above adjacent ground level.
(2)Except as provided in Sentence (3), the anchor systems in Sentence (1) shall be designed, installed and tested in conformance with CSA Z271, "Design of suspended access equipment."
(3)Other anchor systems may be used where such systems provide an equal level of safety.
(4)The anchor system material shall be made of stainless steel, or other corrosion resistant base material, or from steel that is hot dipped galvanized, in accordance with CSA G164, "Hot dip galvanizing of irregularly shaped articles."
OBC SB-13 1.1.1.1. Application
Open OBC SB-13 1.1.1.1. in the code viewer(1)Except as provided in Sentence (2), this Supplementary Standard applies to glass used in interior and exterior guards in buildings described in Sentence 1.3.3.2.(1) of Division A of the Building Code.
(2)This Supplementary Standard does not apply to glass used in
(a)guards at locations referred to in Sentence 3.3.4.7.(1) of Division B of the Building Code, or
(b)walls that act as guards.
OBC SB-13 2.1.1.1. Safety Glass
Open OBC SB-13 2.1.1.1. in the code viewer(1)Glass other than safety glass shall not be used in a guard.
(2)Glass in a guard shall conform to Table 2.1.1.1.
OBC SB-13 Table 2.1.1.1. Selection of Glass in a Guard — Forming Part of Sentence 2.1.1.1.(2)
Open OBC SB-13 Table 2.1.1.1. in the code viewerTable 2.1.1.1. — Selection of Glass in a Guard — Forming Part of Sentence 2.1.1.1.(2) Location of Glass in a Guard | Type of Glass Required Glass located beyond the edge of a floor or within 50 mm of the edge of a floor | Heat strengthened laminated glass Glass located more than 50 mm inward from the edge of a floor | Heat strengthened laminated glass Glass located more than 50 mm inward from the edge of a floor | Heat soaked tempered glass Glass located more than 150 mm inward from the edge of a floor | Heat strengthened laminated glass Glass located more than 150 mm inward from the edge of a floor | Heat soaked tempered glass Glass located more than 150 mm inward from the edge of a floor | Tempered glass not more than 6 mm thick Column 1 | 2
OBC SB-13 3.1.1.1. Structural Design
Open OBC SB-13 3.1.1.1. in the code viewer(1)Glass in a guard shall conform to the requirements of Part 4 of Division B of the Building Code. (See Appendix A.)
(2)Glass in a guard shall not be in direct contact with any metal or similar hard elements forming part of the guard or supporting structure.
(3)Sufficient allowances shall be incorporated for glass in a guard to permit,
(a)deflection and movement under loads, and
(b)expansion and contraction due to temperature changes.