One Building Code issue that tends to present itself on many projects is the difference between an exit and a means of egress.  It’s a subtle difference but can be an important one and it is not well understood.

The following are the relevant definitions found in Article 1.4.1.2. of Division A of the National Building Code:

• Means of egress means a continuous path of travel provided for the escape of persons from any point in a building or contained open space to a separate building, an open public thoroughfare, or an exterior open space protected from fire exposure from the building and having access to an open public thoroughfare.  Means of egress includes exits and access to exits.
• Access to exit means that part of a means of egress within a floor area that provides access to an exit serving the floor area.
• Exit means that part of a means of egress, including doorways, that leads from the floor area it serves to a separate building, an open public thoroughfare, or an exterior open space protected from fire exposure from the building and having access to an open public thoroughfare.  (Exits include doors or doorways leading directly into an exit stair or directly to the outside.  In the case of an exit leading to a separate building, exits also include vestibules, walkways, bridges or balconies.)
• Floor area means the space on any storey of a building between exterior walls and required firewalls, including the space occupied by interior walls and partitions, but not including exits, vertical service spaces, and their enclosing assemblies.

From these definitions, it is apparent that an access to exit is found in the floor area of a building and can include egress stairs, doorways, public corridors and corridors serving the public, while an exit is located outside the floor area.  Means of egress are the combination of both access to exit through the floor area and the exits themselves.

Section 3.3. of the Building Code addresses Safety within Floor Areas and contains the requirements for access to exit through the floor area, whereas  Section 3.4. contains the requirements for exits. 

Although there are many similar requirements for exits and access to exits, an exit is held to a much higher standard.  An exit is expected to provide a higher level of protection from fire exposure both within the floor area and from the lower floor areas that would be passed while using the exit.  In one storey buildings, exits are typically exterior exit doors.  In multi-storey buildings, exits typically consist of fire rated exit stairs connected to exterior doors but exits may also consist of exterior unenclosed stairs protected from radiation exposure in the building. 

The exit is one of the most important passive fire protection elements in a building, and is fundamental in the event of an emergency. It is building occupants’ life-line out of a building, as well as safe access into the building for emergency responders.

– KILO LIMA CODE INC.

Exit integrity [3.4.4.4.] is protected by limiting the openings in the exit fire separations.  Exits are not permitted to contain occupancies and flame-spread ratings are limited to 25.  Wired glazing is limited in fire separations, temperature rise limits may be required for doors and hold-open devices may not be permitted in some scenarios.  In contrast, a public corridor which is an access to exit may contain an occupancy, is permitted a higher flame-spread rating and may not be required to be fire separated from a floor area.

When applying the Building Code, it is important to understand the difference between an exit and an access to exit in order to determine whether the requirements of Section 3.3. or Section 3.4. are applicable to a specific door, corridor, stair or enclosure.

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Want to go deeper?

If you want more information on exits, you can check out our previous blog post Guide to Exits – Part 1 which has a free downloadable Guide to Exit Design.

Exits and egress are also covered in depth in the Kilo Lima Code School Building Codes: Part 3 Fundamentals course.