Commercial stair code is more demanding than residential stair code, and the differences matter at the fabrication stage. Stair width, riser geometry, guard sphere-passage, handrail continuity, and the rules around required exits are all set by the BC Building Code Part 3 or the Vancouver Building By-law for projects inside the City of Vancouver. This article is not a substitute for code review by the authority having jurisdiction (AHJ), an architect, or an engineer.
Two code packages, one stair
Commercial buildings in Metro Vancouver are usually governed by either the BC Building Code Part 3 (Provincial) or the Vancouver Building By-law (City of Vancouver). The two are aligned at a high level, but the editions and amendments are not identical. The first code question on every commercial stair project is which package applies and which edition the AHJ is enforcing.
- BCBC Part 3: most commercial, assembly, institutional, and larger residential buildings outside Vancouver.
- VBBL: equivalent provisions inside the City of Vancouver, with city-specific enforcement.
- Edition matters — code changes are issued periodically by the Province of BC and the City.
- Always confirm the active edition with the AHJ at permit application.
Where to read the code yourself
The BC Building Code is administered by the Province of British Columbia through the Building and Safety Standards Branch. Project teams can review the official BC Codes information at the Province of BC building codes page. Vancouver-specific projects can review the Vancouver Building By-law. For specific provisions, refer to the current edition under the project's permit submission date and confirm interpretation with the AHJ.
Width, riser, and run rules are stricter than residential
Required exit stairs in commercial occupancies follow tighter rules than residential stairs on minimum width, riser height, tread depth, and the relationship between riser height and tread depth. The exact dimensions depend on the occupancy, the occupant load, and the code edition. Designers should pull the current provisions from the relevant code section rather than relying on remembered numbers.
Guards and handrails are non-negotiable
Commercial stairs almost always need a continuous, graspable handrail on both sides, with code-defined profile and projection. Guards must satisfy a minimum height and a sphere-passage rule that limits openings within the guard. Glass, cable, perforated steel, and picket guards can each meet the rule, but the connection detail and the post spacing change with the system. Settle the handrail and guard strategy at shop-drawing review.
Open risers and assembly use are restricted
Open-riser stairs are usually restricted on required exit stairs in assembly and many commercial occupancies. Lobby feature stairs and non-required stairs sometimes allow open risers, subject to the AHJ. Treat open risers as a feature decision, not a default — confirm with the architect of record before fabrication is set.
January 2026: BC now allows single-exit staircases in six-storey residential buildings
The BC Building Code was amended in 2024 to permit single-exit stair (SES) designs for residential buildings up to six storeys. The City of Vancouver adopted the amendment effective January 20, 2026. Previously, buildings three storeys and higher required two egress stairwells. SES buildings require full sprinklers, mechanical smoke management, and a wider stairwell clear width than the standard residential minimum. For fabricators, wider stair sections, heavier structural members, and smoke-management coordination are common scope additions. See our detailed breakdown at BC single-exit staircase 2026 — what it means for builders.
- Applies to residential buildings up to 6 storeys — not commercial or mixed-use without AHJ review.
- Wider stairwell required — confirm clear width with structural engineer and AHJ for SES design.
- Sprinkler system + smoke management are mandatory co-requirements.
- City of Vancouver: adopted Jan 20, 2026. Other Metro Vancouver municipalities adopting separately.
- Fabrication scope for SES stairs is larger — engage the fabricator early in schematic design.
Inspections and documentation are part of the scope
Most commercial stair projects need shop drawings, sealed structural review of the stringers and connections, and on-site inspections during fabrication and install. The fabricator's documentation package — drawings, mill certs for structural steel, weld procedure specifications where applicable, and installation reports — is part of the building's record. Plan the documentation as part of the schedule, not as an afterthought.
Related questions
Does every commercial stair need sealed engineering?
Most commercial stairs require sealed structural review of the stringers, the connections, and the anchor points. Some smaller, light-duty service stairs in certain occupancies are exempt; required exit stairs and any feature stair carrying significant load almost always need a sealed review by the structural engineer of record or a stair-specific engineer.
What are the BCBC width and riser dimensions for an exit stair?
The exact width and riser dimensions depend on the occupancy, the occupant load, and the code edition that applies to the project. Refer to the current BCBC Part 3 or VBBL provisions for the project's permit submission date, and confirm interpretation with the AHJ. Do not rely on a remembered number — the code is updated periodically.
Are open-riser stairs allowed in commercial buildings?
Open-riser stairs are usually restricted on required exit stairs in assembly, institutional, and many commercial occupancies. Non-required and feature stairs sometimes allow open risers, subject to AHJ approval. The architect of record assigns each stair to its category based on the project's occupancy and exit requirements.
Who confirms code compliance on a commercial stair?
Code compliance is the responsibility of the architect of record and the structural engineer of record on most commercial projects. The AHJ reviews the permit submission and inspects the work. The fabricator's role is to deliver steel that matches the approved drawings and the engineer's specifications, with documentation that supports the building's permit record.
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