Exit Access Stairways Connecting More Than 2 Stories- Is it ever possible

[gtyler75]

I will be referencing the 2015 Michigan Building Code, and am most interested in the implications for R-2 buildings.

Here is the code conflict I'm trying to understand:
1006.3 Egress From Stories or Occupied Roofs states "The path of egress travel to an exit shall not pass through more than one adjacent story." As far as I'm aware, there are no exceptions to this statement.

Meanwhile, Section 1019 Exit Access Stairways and Ramps includes the following exception I am hoping to apply: 1019.3 Exception 4 "Exit access stairways and ramps in buildings equipped throughout with an automatic sprinkler system... this provision is limited to openings that do not connect more than four stories."

There seems to be a conflict here. Under any circumstance, it seems that 1006.3 would prevent an exit access stairway from connecting more than two stories, so how could the exception in 1019.3 ever be possible? Is traveling down an exit access stair not considered passing through adjacent stories?

Appreciate the clarification.

 

[Paul Sweet]

My guess is that the stairway could connect up to four stories, but you could only use it as an exit access from one of those stories. It could be used for circulation only between the other stories.

 

[gtyler75]

My guess is that the stairway could connect up to four stories, but you could only use it as an exit access from one of those stories. It could be used for circulation only between the other stories.

Hmm, that would seem very impractical - if the topmost story can egress safely why would the floors below have any issue?

Does anyone have a real-world example where this exception has been applied? I just don't understand where it would be useful to connect stories with a stair but not allow more than one to use it as an exit access.

 

[Blazer]

You could use exit access stair to get off of 4th story but would have to enter an interior exit stairway on the 3rd story. Travel distance includes down the stair until reaching an exit on 3rd story.

 

[ccollings]

my interpretation is that if the stairway goes goes directly to the level of egress then it is not passing through a story. an example of passing through another story is that you have a stair from third floor to second floor and then you have to go down a hallway to a stair from second to ground floor. that is "passing through" another story.

 

[Blazer]

I'll refer you to the 2018 IBC code and commentary which debunks your interpretation. The reason its limited to just one adjacent story is because travel is faster horizontally than vertically, thus the reason for requiring exit access to travel just one story before reaching an interior exit stairway, exit discharge, or exit passageway. Also the reason the travel distance is measured down the nose of the stair treads.

 

[RPD1]

Hi @Blazer. I have a question about about the adjacent story.


If I have an exit access stair with 3 stories with an exit on the 1st story does passing through the 2nd story to get to the exit on the 1st story meet the requirements of 1006.3.1?

 

[Yankee Chronicler]

It may help to look at the Commentary. From the 2021 IBC Commentary for section 1019.3:

The base requirement is that exit access stairways
between floors are permitted and protected in a similar
manner as floor openings (see Sections 712 and 713).
A stairway penetrates the floor/ceiling assemblies
between levels, creating a vertical opening or shaft. In
cases of fire, a vertical opening may act as a chimney,
causing smoke, hot gases and light-burning products
to flow upward (buoyant force). If an opening is unprotected,
these products of combustion will be forced by
positive pressure differentials to spread horizontally
into building spaces. There are exceptions for shaft
protection around openings in Section 712.1 or exit
access stairways as permitted in this section in Exceptions
1 through 9 (see also Section 712.1.12).

Then we move on to the exceptions. Exception #4, the one you want to use, has the following Commentary:

Exception 4 discusses buildings sprinklered
throughout with an NFPA 13 system. The size of the
opening is limited to twice the size of the stairway footprint.
The opening must be protected with a draft curtain
and closely spaced sprinklers (see Commentary
Figure 1019.3). This allows for such an opening to
extend the entire height of the building. For groups
other than business and mercantile, there is the additional
limitation of a maximum of four stories. However,
to serve as one of the required ways off the floor
(means of egress via access to exits), the exit access
stairway must still meet the exit access travel distance
(see Section 1017.3.1) and cannot be used for more
than one story (see Section 1006.3.2) before occupants
have access to exits. This item is similar to what
is permitted for escalators (see Sections 712.1.3 and
712.1.3.1). The power-operated automatic shutter permitted
in Section 712.1.3.2 would not be an option for
exit access stairways since the stairways must be
available for exit access travel.

So the stair and floor opening can connect more than one story, but the exit access travel is still limited to one story before occupants have access to an enclosed, protected exit or an exit discharge door to the outside.

 

[RPD1]

Thank you, @Yankee Chronicler!

 

[Blazer]

Hi @Blazer. I have a question about about the adjacent story.


If I have an exit access stair with 3 stories with an exit on the 1st story does passing through the 2nd story to get to the exit on the 1st story meet the requirements of 1006.3.1?
View attachment 14845

Yes, as long as you have an interior exit stair enclosure that serves level 2 (exit door into the protected interior exit stairway) then it complies with 1006.3.1. This means the enclosed stair must serve as an "exit" that is protected in accordance with 1023.1. If connecting three stories it shall be 1-hour fire resistance rated. Could be exterior exit stair too if you don't want interior exit stair. Remember third story requires no less than 2 exit/exit access (Refer to 1006.3.3).
The opening must be protected in accordance with 712.1.12 for exit access. Using exception #4 of 1019.3 (draft curtain and closely spaced sprinklers) to prevent enclosing the openings (connecting three stories) which is permitted.

 

[RPD1]

Yes, as long as you have an interior exit stair enclosure that serves level 2 (exit door into the protected interior exit stairway) then it complies with 1006.3.1. This means the enclosed stair must serve as an "exit" that is protected in accordance with 1023.1. If connecting three stories it shall be 1-hour fire resistance rated. Could be exterior exit stair too if you don't want interior exit stair. Remember third story requires no less than 2 exit/exit access (Refer to 1006.3.3).
The opening must be protected in accordance with 712.1.12 for exit access. Using exception #4 of 1019.3 (draft curtain and closely spaced sprinklers) to prevent enclosing the openings (connecting three stories) which is permitted.

Sorry @Blazer, I should have been more clear. In this scenario occupants would be starting on Level 3 and traveling down to a exit at Level 1. They would pass through Level 2 but not exist the Exit Access Stair. See proposed egress path in blue below.

We do have a separate enclosed egress stair serving both Level 2 and 3.

 

[Blazer]

Sorry @Blazer, I should have been more clear. In this scenario occupants would be starting on Level 3 and traveling down to a exit at Level 1. They would pass through Level 2 but not exist the Exit Access Stair. See proposed egress path in blue below.

We do have a separate enclosed egress stair serving both Level 2 and 3.

View attachment 14847

There is no required exit access traversing more than one adjacent story then if you have the exit enclosure serving level 2 and 3. Just because you have a monumental stair connecting three stories doesn't make it required to traverse two stories (more than one adjacent story). Once you travel from level 3 to level 2 the occupants can reach an exit on level 2 (interior exit stairway). Occupants traveling from level 2 to level 1 can reach an exterior exit door on level 1.

***Just because you can traverse two stories doesn't mean you shall be required to traverse two stories! The blue travel path is not the required path to reach an exit. I am able to use the green path so compliance with 1006.3.1 is met. The code intentions are to avoid unprotected vertical travel to reach an exit. Sometimes it helps to not focus on what the code words mean; focus on what their goal is.

 

[RPD1]

Thank you @Blazer!

If I am relying on the exit access stair as my required second means of egress from Level 3, does the entrance to the enclosed stair at Level 2 need to be within the 250' from the most remote point on Level 3 (green path below), or because there is a an exit enclosure to Level 3 that users can go directly to the exit enclosure (blue path below) is this not required.

 

[Blazer]

Travel distances shall only be measured from furthest point to an exit. Its not a requirement to meet travel distances to every exit, if that was the case every building would be a small box like McDonalds Happy Meal.