Canada · Building code

What are the building code requirements for atriums and vertical openings in Canada?

Atriums and vertical openings must meet specific fire separation, smoke control, sprinklering, and construction requirements that vary with building height, occupancy, and the number of interconnected storeys.

Atriums create design challenges because they connect multiple storeys through a single open volume. The building code addresses this with layered requirements covering fire separations around the atrium, smoke management systems, sprinkler protection, and limits on the number of interconnected floors. The answer depends on the building's height, occupancy classification, and whether the atrium qualifies as an interconnected floor space or a full vertical service space.

What to check first

  • Determine whether the opening qualifies as an atrium, interconnected floor space, or vertical service space — each triggers different code paths.
  • Smoke control or smoke management is typically required for atriums connecting more than a limited number of storeys.
  • Sprinklering and fire separation requirements around the atrium perimeter depend on occupancy and building height.

Jurisdiction notes

National baseline

The NBC addresses atriums primarily through interconnected floor space and vertical service space provisions, with specific smoke control and fire separation requirements.

Provincial adoption

Check whether your province amends the NBC atrium provisions — some jurisdictions add stricter smoke management or sprinkler requirements.

Project variables

Building height, number of connected storeys, occupancy mix, and sprinkler status all influence which requirements apply to the atrium design.

Not professional advice

CodeCan reports what the published building code says. It is not legal, engineering, or architectural advice, and it does not certify compliance. Building codes are adopted and amended provincially and enforced locally — always verify with your authority having jurisdiction (AHJ) before you build.

Work through it in this order

  1. Classify the vertical opening as an atrium, interconnected floor space, or vertical service space.
  2. Check the NBC provisions for the applicable opening type, including fire separation and smoke control requirements.
  3. Verify sprinklering requirements and any limits on the number of interconnected storeys.
  4. Confirm provincial adoption and any local amendments that affect the design.

Common questions

Is an atrium the same as an interconnected floor space under the NBC?

Not always. The code distinguishes between different types of vertical openings, and the specific classification affects which requirements apply.

When is smoke control required for an atrium?

Smoke control requirements typically apply when the atrium connects more than a specified number of storeys, but the exact threshold depends on occupancy and sprinkler status.

Can an atrium be open without fire separations?

In some conditions with sprinklering and limited storey connections, reduced fire separation may be permitted, but this depends on the specific code provisions and provincial adoption.