Exit Corridor Width – How to determine – Building Codes


Exit Corridor Width – Building Codes

Exit Corridor Width  is determined by the code.  As an Architect, I interact with clients, engineers and contractors who have acquired bits of information about Building Codes.  Sometimes, those bits are misconceptions and regurgitated information heard along their travels.

When I first began my architectural career over 25 years ago, I found the code book very intimidating.   There are classes and seminars to get a better understanding of the Building Codes, but just like many things, jumping in feet first is how you learn.  The code has no beginning or end, so the question is where to start.

Upcoming Blog Posts

In the next series of blog posts, I will explore common simple and more complex Building Codes.    Each City has adopted a code but most in Arizona use the IBC (International Building Code).

The issues to be addressed in the following Blog Posts are:

  1. Door swing direction.  Which way should the door swing, out of a room or in?
  2. Number of exits within a room?
  3. Door Size.  Who said “size doesn’t matter.”
  4. Exit corridor width.  How narrow can a hallway be?
  5. Clearances around a door?  Door arrangement between two doors.  Helpful if your using a wheelchair or trying to bring supplies to your space.
  6. Door fire ratings.  Is your door fire rated
  7. Exit Travel Distance.  There is a maximum number of feet one can travel before exiting a space.
  8. When is an elevator required?
  9. Number of plumbing fixtures required? 

The item in bold to be addressed in this post.  As an Arizona Architect, most City’s jurisdictions work with the IBC (International Building Code).   The code analysis is based upon the IBC.

Exit Corridor Width

Exit corridors are the enclosed exit access component that provides a path of egress outside of the building.  The size of the corridor is to allow for safe passage of occupants within the building.  Exit corridor is determined by minimum size requirements and occupancy loads.  As you explore the code, you see a trend that occupancy load effects many elements of the building.

Exit corridor width - Serbin Studio Inc.

The code indicates: Minimum exit corridor width  44″ with some exceptions.  See occupancy calculations below.

  • 24″ for access to electrical, mechanical  or plumbing systems
  • 36″ for occupant loads less than 50
  • 36″ in residential
  • 72″ in Educational occupancy with greater than 100 occupants
  • 72″ in medical facilities with gurney’s
  • 96″ in  in Group I-2 for bed movement which essentially is hospital, nursing homes etc.

Height of ceilings within corridor must maintain 7′-6″ minimum.

Occupancy calculations

Besides the minimum requirements, the # of occupants also determine size of exit corridors.  In building over 1 story, stairwell may determine corridor width as well.

Total width of corridor = # of occupants (times) 0.2″/ per occupant

Total width of stairwell = # of occupants (times) 0.3″ / per occupant

Which ever number is greater takes precedent.   See example below.

Exit corridor width - Serbin Studio Inc.

In addition to minimum corridor width, additional code requirements may take precedence.  For example, ADA door clearances.   Also door swings can effect corridor widths as they can only minimally impede the corridor if swinging into it.  Those issues will be explained in a later blog post

Summary

The width of a corridor is dependent upon minimum requirements, calculations based upon the number of occupants within a building and door clearances.  As the buildings become larger and have larger # of occupants, such as building with assemblies, the corridor width can grow significantly.

So when desiging a new building, size the corridor accordingly.  When retrofitting an existing facility and have a change of occupancy type, verify if the existing corridors can handle the change in the # of occupants.   However when in doubt, rely on an Architect to explore the code and assist you.

Jeff Serbin

Jeff Serbin

Jeff Serbin is Vice President of Serbin Studio. His responsibilities include architectural design and project management. He coordinates the work of consultants and design team members, and is involved in design from concept through construction.

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