Exit Passageway Width

Exit Passageway Width

The required width of an exit passageway is governed by BC Section 1005 and BC Section 1020.2. The latter tends to be the more strict and therefore governing requirement. However, you still need to demonstrate that your stair complies with both Building Code Sections.

Building Code Section 1005 requirements

You must first calculate the occupant load of the space being served by the exit passageway.
Then the minimum width of the exit passageway is calculated by using the appropriate factor from Table 1005.1. (Hint: exit passageway falls under “other components”.)


Example:  For a space that has an occupancy load of 150 people, 150x 0.2 = 30. Therefore, a minimum passageway width of 30 inches is required.

egress width table

TABLE 1005.1 Egress Width

Building Code Section 1020.2 requirements

Generally, this section requires a minimum exit passageway width of 44 inches. So if you have an occupant load of less than 220 (44/0.2=220), BC Section 1020.2 will govern over BC Section 1005.1 when it comes to the width of the exit passageway. The required width of the exit passageway must not be obstructed.

Exit Passageway Width Exceptions

A minimum exit passageway of 36 inches is also permitted according to BC Section 1020.2 if it serves an occupant load of 50 or less

Exceptions to no obstructions rule

  • handrails may not reduce required width by more than 7 inches
  • doors when fully open may not reduce required width by more than 7 inches
  • doors in any position may not reduce required width by more than 50%
  • nonstructural projections such as trim and other decorative features are allowed to project into the required width by no more than 1.5 inches on each side.

Avoid this Exit Passageway Design Mistake

“Once a given level of exit protection is achieved, such level of protection shall not be reduced until arrival at the exit discharge.”
- BC Section 1017.1

In other words, never reduce the width of an exit passageway in the direction of travel to the exit, larger to smaller. You can’t reduce the width even if the smaller width complies with the above sections.
You can imagine why going from a larger width passageway to a smaller one towards the exit door would be a dangerous scenario, creating a bottle neck effect if an evacuation was required. Yikes!

Exit Passageway Bottleneck

Exit Passageway Bottleneck

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