National baseline
The NBC references CSA S16 for structural steel design and CSA S136/AISI S240 for cold-formed steel. Fire-resistance requirements depend on building classification, height, and area.
Canadian building code question
What are the building code requirements for steel frame construction in Canada?
Steel-frame buildings must be designed per CSA S16 for structural steel or AISI S240 for cold-formed steel framing, meet fire-resistance rating requirements through applied fireproofing or alternative methods, and comply with connection, bracing, and seismic design provisions.
Steel construction in Canada follows referenced standards for structural design while the building code governs fire protection, building height and area limits, and seismic performance. Whether the project uses hot-rolled structural steel or cold-formed steel framing, the code path differs in design standard, fire protection approach, and height/area calculations. Understanding which standard applies is the first step.
What to check first
- Determine whether the project uses hot-rolled structural steel (CSA S16) or cold-formed steel framing (AISI S240/CSA S136) and apply the correct referenced design standard.
- Check fire-resistance rating requirements for the steel structure, including whether applied fireproofing, enclosure, or alternative methods are needed.
- Verify seismic design category and detailing requirements for steel connections and bracing systems.
Jurisdiction notes
Fire protection
Unprotected steel has limited fire resistance. The code determines whether spray-applied fireproofing, intumescent coatings, or concrete encasement is needed based on the required rating.
Seismic design
Steel buildings must meet seismic force-resisting system requirements including ductility detailing that varies by seismic hazard zone and the structural system selected.
Work through it in this order
- Classify the building and determine height, area, and construction type to establish the fire-resistance rating requirements for the steel structure.
- Select the structural system and confirm the applicable design standard (CSA S16 or AISI S240).
- Determine the seismic force-resisting system and ensure the connection and bracing details meet the required ductility category.
- Specify the fire protection method for structural steel members to achieve the required fire-resistance rating.
Common questions
Is steel frame construction considered noncombustible?
Yes, steel is classified as noncombustible construction material. However, noncombustible construction still requires fire-resistance ratings for structural members, which unprotected steel may not achieve without applied fireproofing.
When is fireproofing required on structural steel?
Whenever the building code requires a fire-resistance rating for the structural assembly. The required rating depends on building classification, height, area, and occupancy.
Can cold-formed steel be used for multi-storey buildings?
Yes, within the height and area limits for the applicable construction type. Cold-formed steel framing is commonly used in mid-rise residential and commercial buildings.