Talking in Code: Exit access corridor
Want to know more about roof truss failures? Have a question about fire-rated assemblies? Confused about safety glazing on windows and door? In our monthly column — Talking in Code — International Code Council code experts will address some of the typical questions asked of our technical services team regarding current code issues. This feature is not an ICC code opinion, nor is it a committee interpretation, but it is intended to provide clarification of code text for adopting jurisdictions, design professionals and members of the construction industry.
International Code: 2015 International Mechanical Code
Question: Can a corridor in a Group R-2 apartment building supply makeup air to a dwelling unit to serve as the makeup air for the bathroom exhaust for a bathroom located in the dwelling unit?
Answer: The corridor in question is considered an exit access corridor. Section 601.2 does not permit an exit access corridor to serve as a supply, return, exhaust, relief or ventilation air duct. Exception #1 of Section 601.2, however, allows the corridor to supply air to be used for makeup air in rooms that open directly onto the corridor such as toilet rooms, bathrooms and janitor closets. These rooms would have an exhaust fan and the corridor would supply the makeup air for the exhaust fan. There would have to be an equal amount of outdoor air supplied directly to the corridor that would equal the amount of makeup air supplied by the corridor to the adjacent toilet room or similar space.
In your situation, the room that opens directly into the corridor is the dwelling unit. The room that requires the exhaust is the toilet room in the dwelling unit. Since the makeup air would have to go through the dwelling unit to get to the toilet room, the toilet room is not considered to be opening directly onto the corridor and, therefore, this Exception #1 of Section 601.2 would not apply.
As always, code opinions issued by International Code Council staff are based on published Code Council codes and do not include local, state or federal codes; policies; or amendments. This opinion does not imply approval of an equivalency, specific product, specific design or specific installation and cannot be published in any form implying such approval by the International Code Council. As this opinion is only advisory, the final decision is the responsibility of the designated authority charged with the administration and enforcement of this code. All code citations reference the 2015 and 2018 International Codes unless otherwise specified.