Part 9 glass, guards, handrails, stairs and fire-related structure

Glass and windows

Glass must meet one of the CGSB or ASTM standards listed in 9.6.1.2. Mirrored glass doors are allowed only at clothes closet entrances OBC Div. B 9.6.1.2.OBC Div. B 9.6.1.2. Material Standards for Glass(1) Glass shall conform to (a) CAN/CGSB-12.1, "Safety Glazing," (b) CAN/CGSB-12.2-M, "Flat, Clear Sheet Glass," (c) CAN/CGSB-12.3-M, "Flat, Clear Float Glass," (d) CAN/CGSB-12.4-M, "Heat Absorbing Glass," (e) CAN/CGSB-12.8, "Insulating glass units," (f) CAN/CGSB-12.9, "Spandrel glass," (g) CAN/CGSB-12.10-M, "Glass….

Structurally, glass is designed to 4.3.6.1 OBC Div. B 9.6.1.3.OBC Div. B 9.6.1.3. Structural Sufficiency of Glass(1) Except as provided in Sentence (2), glass shall be designed in conformance with Article 4.3.6.1. (2) Where the building has an essentially uniform distribution of paths for air leakage, including operable openings, but no large openings that would permit wind gusts to rapidly enter the building and the building is…. Window panes may use the area tables 9.6.1.3.-A to -F only if all of these hold:

• air leakage paths are spread evenly over the building;
• there are no large openings that would let wind gusts in;
• the building is not in an exceptionally exposed spot, such as a hilltop.

Door panes use Table 9.6.1.3.-G.

Article 9.7.2.2 is a signpost for windows and doors OBC Div. B 9.7.2.2.OBC Div. B 9.7.2.2. Other Requirements for Windows, Doors and Skylights(1) Minimum sizes of doorways and doors within a barrier-free path of travel shall conform to Section 9.5. (2) The protection of window and door openings to protect persons from falling through them shall conform to Article 9.8.8.1. (3) Properties of windows and doors within exits shall conform to Section 9.9. (4)…. Protection against falling through openings is in 9.8.8.1 OBC Div. B 9.8.8.1.OBC Div. B 9.8.8.1. Required Guards(1) Except as provided in Sentence (2) and except at the leading edge at the top of a flight, every surface to which access is provided, including but not limited to flights of steps and ramps, exterior landings, porches, balconies, mezzanines, galleries and raised walkways, shall be protected by a guard on each side…. In residential occupancies, an openable window needs either a guard or a tool-release limiter that keeps the opening to 100 mm or less. The exception is a window whose openable part is either:

• more than 900 mm above the floor; or
• less than 1,800 mm above the ground outside.

Glazing over stairs and landings follows the same idea. If it comes within 1,070 mm of the tread (900 mm inside a dwelling unit), it needs a guard, or it must be fixed and designed for the 4.1.5.14 guard loads.

Stud walls around the main bathroom of a dwelling unit get blocking for future grab bars at the water closet, shower and tub OBC Div. B 9.5.2.4.OBC Div. B 9.5.2.4. Stud Wall Reinforcement(1) If wood wall studs or sheet steel wall studs enclose the main bathroom in a dwelling unit, reinforcement shall be installed to permit the future installation of the following: (a) for a water closet, a grab bar described in Clauses 3.8.3.8.(3)(a) and a grab bar described in Clause 3.8.3.8.(3)(c), (b) for a shower….

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Guards and handrails

A guard is required wherever a walking surface is more than 600 mm above the adjacent surface within 1.2 m. Guard loads come from Table 9.8.8.2.OBC Div. B Table 9.8.8.2. Minimum Specified LoadsTable 9.8.8.2. — Minimum Specified Loads Forming Part of Sentence 9.8.8.2.(1) Location of Guard | Horizontal Load Applied Inward or Outward at any Point at the Minimum Required Height of the Guard | Horizontal Load Applied Outward on Elements Within the Guard, Including Solid Panels and Balusters | Evenly Distributed…:

Swipe sideways to see the whole table

The loads need not act at the same time. In dwelling units, a balustrade load is spread to engage three balusters where they fall within 300 mm OBC Div. B 9.8.8.2.OBC Div. B 9.8.8.2. Loads on Guards(1) Except as provided in Sentences (2), (3), (5) and (6), guards shall be designed to resist the specified loads prescribed in Table 9.8.8.2. (2) The size of the opening between any two adjacent vertical elements within a guard shall not exceed the limits required by Sentence 9.8.8.5.(1) when each of these elements…. Guards built to SB-7, "Guards for Housing and Small Buildings", are deemed to comply.

Glass in guards is safety glass of the laminated or tempered type to CAN/CGSB-12.1, or wired glass to CAN/CGSB-12.11-M OBC Div. B 9.8.8.7.OBC Div. B 9.8.8.7. Glass in Guards(1) Glass in guards shall be (a) safety glass of the laminated or tempered type conforming to CAN/CGSB-12.1, "Safety Glazing," or (b) wired glass conforming to CAN/CGSB-12.11-M, "Wired Safety Glass.". Garage floors and ramps 600 mm or more above the adjacent level need a curb of at least 140 mm and a guard of at least 1,070 mm. Vehicle guardrails take the 22 kN load of 4.1.5.15 OBC Div. B 9.8.8.4.OBC Div. B 9.8.8.4. Guards for Floors and Ramps in Garages(1) Except for floors of garages referred to in Section 9.35., where garage floors or ramps are 600 mm or more above the adjacent ground or floor level, every opening through a garage floor and the perimeter of floors and ramps that have no exterior walls shall be provided with (a) a continuous curb not less than 140….

Handrails resist a 0.9 kN point load in any direction. Handrails not serving a single dwelling unit also take 0.7 kN/m OBC Div. B 9.8.7.7.OBC Div. B 9.8.7.7. Design and Attachment of Handrails(1) Handrails and their supports shall be designed and constructed to withstand the following loads, which need not be considered to act simultaneously: (a) a concentrated load of not less than 0.9 kN applied at any point and in any direction for all handrails, and (b) for handrails other than those serving a single…. In a single dwelling unit, a handrail fixed to wood studs or blocking is deemed to comply if all three of these are met:

• attachment points at no more than 1.2 m;
• the end attachments within 300 mm of the ends;
• two No. 8 wood screws at each point, penetrating at least 32 mm into solid wood.

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Stairs

Stairs and ramps take a uniform load of 1.9 kPa if they serve only one dwelling unit (or a house with a secondary suite), and 4.8 kPa otherwise OBC Div. B 9.8.9.1.OBC Div. B 9.8.9.1. Loads on Stairs and Ramps(1) Except as specified in Articles 9.8.9.4. and 9.8.9.5., stairs and ramps shall be designed for strength and rigidity under uniform loading criteria to support specified loads of (a) 1.9 kPa for stairs and ramps serving not more than one dwelling unit or a house with a secondary suite including their common spaces….

Wood stringers OBC Div. B 9.8.9.4.OBC Div. B 9.8.9.4. Wooden Stair Stringers(1) Wooden stair stringers shall (a) have a minimum effective depth of 90 mm, measured perpendicularly to the bottom of the stringer at the point of minimum cross-section, and an overall depth of not less than 235 mm, (b) be supported and secured top and bottom, (c) be not less than 25 mm actual thickness if supported…:

• effective depth of at least 90 mm, measured square to the bottom edge at the narrowest point after cutting;
• overall depth of at least 235 mm;
• 25 mm thick if supported along their length, 38 mm if not;
• spacing up to 900 mm in single-dwelling stairs (1,200 mm where risers support the tread fronts), and 600 mm in other stairs.

Treads in dwelling units are at least 25 mm thick, or 38 mm with open risers and stringers more than 750 mm apart OBC Div. B 9.8.9.5.OBC Div. B 9.8.9.5. Treads(1) Stair treads of lumber, plywood or O-2 grade OSB within dwelling units shall be not less than 25 mm actual thickness, except that, if open risers are used and the distance between stringers exceeds 750 mm, the treads shall be not less than 38 mm actual thickness. (2) Stair treads of plywood or OSB, that are not….

Exterior concrete stairs with more than 2 risers sit on walls or piers at least 150 mm across, or are cantilevered from the foundation OBC Div. B 9.8.9.2.OBC Div. B 9.8.9.2. Exterior Concrete Stairs(1) Exterior concrete stairs with more than 2 risers and 2 treads shall be (a) supported on unit masonry or concrete walls or piers not less than 150 mm in cross-section, or (b) cantilevered from the main foundation wall. (2) Stairs described in Sentence (1), when cantilevered from the foundation wall, shall be…. Cantilevered steps are designed for their loads. They are anchored to concrete foundation walls at least 200 mm thick and protected against frost uplift OBC Div. B 9.8.10.2.OBC Div. B 9.8.10.2. Anchorage(1) Cantilevered concrete steps referred to in Article 9.8.10.1. shall be anchored to concrete foundation walls not less than 200 mm thick..

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Fire-related structure

Several fire rules in 9.10 are really about structure:

• Tents, air-supported structures, transformer vaults, assembly spaces and large basements are sent to Part 3 OBC Div. B 9.10.1.3.OBC Div. B 9.10.1.3. Items Under Part 3 Jurisdiction(1) Tents, air-supported structures, transformer vaults, walkways, elevators and escalators shall conform to Part 3. (2) Where rooms or spaces are intended for an assembly occupancy, such rooms or spaces shall conform to Part 3. (3) Basements containing more than 1 storey or exceeding 600 m² in area shall conform to….
• Structural steel in construction that needs a fire-resistance rating must be protected to give that rating, except as 3.2.2.3 allows OBC Div. B 9.10.7.1.OBC Div. B 9.10.7.1. Protection of Steel Members(1) Except as permitted in Article 3.2.2.3., structural steel members used in construction required to have a fire-resistance rating shall be protected to provide the required fire-resistance rating..
• Combustible framing that bears on or abuts a noncombustible fire separation must be built so that its collapse in a fire does not bring the separation down OBC Div. B 9.10.9.10.OBC Div. B 9.10.9.10. Collapse of Combustible Construction(1) Combustible construction that abuts on or is supported by a noncombustible fire separation shall be constructed so that its collapse under fire conditions will not cause collapse of the fire separation..
• Beam pockets in a masonry or concrete fire separation must leave the equivalent thickness required in SB-2 OBC Div. B 9.10.9.11.OBC Div. B 9.10.9.11. Reduction in Thickness of Fire Separation by Beams and Joists(1) Where pockets for the support of beams or joists are formed in a masonry or concrete fire separation, the remaining total thickness of solid masonry and/or grout and/or concrete shall be not less than the required equivalent thickness shown for Type S monolithic concrete in Table 2.1.1. of MMAH Supplementary….
• A storage garage is separated from other occupancies by 1.5 h, or 1 h if it holds 5 vehicles or fewer. No separation is needed if it serves only the dwelling unit it belongs to OBC Div. B 9.10.9.18.OBC Div. B 9.10.9.18. Separation of Storage Garages(1) Except as provided in Sentences (2) and (3), a storage garage shall be separated from other occupancies by a fire separation having not less than a 1.5 h fire-resistance rating. (2) Except as permitted in Sentence (3), storage garages containing 5 motor vehicles or fewer shall be separated from other occupancies….
• Firewalls in Part 9 buildings follow Part 3 OBC Div. B 9.10.11.3.OBC Div. B 9.10.11.3. Construction of Firewalls(1) Where firewalls are used, the requirements in Part 3 shall apply.. Their structural design load comes from 4.1.5.17.

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