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.
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:
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 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.
The code indicates: Minimum exit corridor width 44″ with some exceptions. See occupancy calculations below.
Height of ceilings within corridor must maintain 7′-6″ minimum.
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.
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
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.