Two Exit Stairs, One Exit Discharge

[MKALLAY]

I am looking at a project (5 stories) that has two exit stairs sharing the same exit passageway to provide exit discharge at grade. The project is under 2021 IBC. Is there any reason this cannot be allowed? I assume the exit passageway must be sufficiently wide to accommodate the combined egress capacity of both stairs. Otherwise, is there anything else that would restrict this configuration?

 

[RLGA]

That is not allowed. Section 1006.3 states the minimum number of "separate and distinct exits" required. When they merge as you have described, they are no longer "separate and distinct."

You can have a separate exit passageway serving each stairway that discharges to the exterior, and, technically, they can be side by side, but they must be separated by construction complying with the requirements for exit passageways.

 

[MKALLAY]

That is not allowed. Section 1006.3 states the minimum number of "separate and distinct exits" required. When they merge as you have described, they are no longer "separate and distinct."

You can have a separate exit passageway serving each stairway that discharges to the exterior, and, technically, they can be side by side, but they must be separated by construction complying with the requirements for exit passageways.

Ah! Good point. But now hypothetically - if the number of exits at each floor level is more than the minimum required, then would the arrangement be acceptable? In the project I am reviewing, there are 4 stairways, in part, it seems, because this is an assembly building with high occupant loads on some floors. It appears the multiple stairs are provided to meet travel distance and capacity. If the two stairs that converge on the discharge level are considered two parts of the same exit element - say stair 1A and 1B - then it becomes analogous to a scissors stair, which is permitted by Code (per 1007.1.1), but cannot be considered separate exits. In such case, is there any other reason they cannot merge?

 

[RLGA]

Ah! Good point. But now hypothetically - if the number of exits at each floor level is more than the minimum required, then would the arrangement be acceptable? In the project I am reviewing, there are 4 stairways, in part, it seems, because this is an assembly building with high occupant loads on some floors. It appears the multiple stairs are provided to meet travel distance and capacity. If the two stairs that converge on the discharge level are considered two parts of the same exit element - say stair 1A and 1B - then it becomes analogous to a scissors stair, which is permitted by Code (per 1007.1.1), but cannot be considered separate exits. In such case, is there any other reason they cannot merge?

If a story requires only two exits and four are provided, which two merge with the other two to create two "separate and distinct" exits at the level of exit discharge, then I could see that being acceptable (or at least defendable should the AHJ push back on the concept).

 

[MKALLAY]

Thanks for that input, RLG!

Just an FYI, I'm not reviewing this as an AHJ, but rather providing preliminary review in house - so my objective is to always flag an issue before it gets too far. That said, I often get push back from designers, or they get it from clients - so I need to be clear when I raise a point as to why it is an issue.

And that said - sometimes "Do the right thing" is the best defense!

 

[Sifu]

Just an FYI, I'm not reviewing this as an AHJ, but rather providing preliminary review in house - so my objective is to always flag an issue before it gets too far. That said, I often get push back from designers, or they get it from clients - so I need to be clear when I raise a point as to why it is an issue.

WHAAAAAAT? QA before it goes out?

 

[Yankee Chronicler]

I am looking at a project (5 stories) that has two exit stairs sharing the same exit passageway to provide exit discharge at grade. The project is under 2021 IBC. Is there any reason this cannot be allowed? I assume the exit passageway must be sufficiently wide to accommodate the combined egress capacity of both stairs. Otherwise, is there anything else that would restrict this configuration?

Coincidentally, I spent today in an ICC training seminar on means of egress. The instructor addressed this specifically. Well, almost -- he spoke about two exit stairways converging and stated that it's not allowed. From that I'm going to infer that if two exit stairs can't converge into a single exit stair, they also can't converge into a single exit passageway.

 

[MKALLAY]

WHAAAAAAT? QA before it goes out?

Yeah, that's just plain crazy talk, huh? ;-)

 

[Inspector Gadget]

Just an FYI, I'm not reviewing this as an AHJ, but rather providing preliminary review in house - so my objective is to always flag an issue before it gets too far.

 

[Bergie3941]

That is not allowed. Section 1006.3 states the minimum number of "separate and distinct exits" required. When they merge as you have described, they are no longer "separate and distinct."

You can have a separate exit passageway serving each stairway that discharges to the exterior, and, technically, they can be side by side, but they must be separated by construction complying with the requirements for exit passageways.

I have a remodel project that has two exit stairways, Stair A discharges directly to the exterior, and Stair B discharges through an exit discharge lobby (1028.1 exception 1). The entrances to both exit stairways at all floors are sufficiently separated (1/3 building diagonal, sprinklered). However, the exit door of Stair A and the lobby exit door discharge to the same general area and are only 18' apart, which is where the question lies. I did the original design in-house (I'm not an architect, no architect required for this project) but we recently hired an architect to help speed the project along, and they are saying that these doors that lead to the exterior need to be separated by the 1/3 distance. I disagree with this, as 1007.1.1 seems to only apply to the doors leading from the exit access. I don't find anything that limits the remoteness of these doors. RLGA's comment seems to agree with my opinion, but I wanted to present my specific situation. This project is under IBC 2018, in North Dakota.

 

[steveray]

I have a remodel project that has two exit stairways, Stair A discharges directly to the exterior, and Stair B discharges through an exit discharge lobby (1028.1 exception 1). The entrances to both exit stairways at all floors are sufficiently separated (1/3 building diagonal, sprinklered). However, the exit door of Stair A and the lobby exit door discharge to the same general area and are only 18' apart, which is where the question lies. I did the original design in-house (I'm not an architect, no architect required for this project) but we recently hired an architect to help speed the project along, and they are saying that these doors that lead to the exterior need to be separated by the 1/3 distance. I disagree with this, as 1007.1.1 seems to only apply to the doors leading from the exit access. I don't find anything that limits the remoteness of these doors. RLGA's comment seems to agree with my opinion, but I wanted to present my specific situation. This project is under IBC 2018, in North Dakota.

I'm going to mildly disagree on intent and common sense......The stair discharge, when reentry is allowed, I would argue is not the "egress discharge" but the exterior door is and needs to be separated from the other exit discharge....Even if the language in the code sucks....

 

[Yankee Chronicler]

I have a remodel project that has two exit stairways, Stair A discharges directly to the exterior, and Stair B discharges through an exit discharge lobby (1028.1 exception 1). The entrances to both exit stairways at all floors are sufficiently separated (1/3 building diagonal, sprinklered). However, the exit door of Stair A and the lobby exit door discharge to the same general area and are only 18' apart, which is where the question lies. I did the original design in-house (I'm not an architect, no architect required for this project) but we recently hired an architect to help speed the project along, and they are saying that these doors that lead to the exterior need to be separated by the 1/3 distance. I disagree with this, as 1007.1.1 seems to only apply to the doors leading from the exit access. I don't find anything that limits the remoteness of these doors. RLGA's comment seems to agree with my opinion, but I wanted to present my specific situation. This project is under IBC 2018, in North Dakota.

I would not allow this, for multiple reasons:

• The rated floor doesn't include the entire area of the discharge lobby
• The two exterior doors are too close together
• The door from the exit stair at lower left into the exit lobby doesn't serve that exit and potentially compromises the fire resistance rating of the stair enclosure at a critical point

1.2. The entire area of the level of exit
discharge is separated from areas below
by construction conforming to the fireresistance
rating for the enclosure

What's the door at the upper right of the exit stair that discharges through the lobby, and why does that door swing out rather than into the stair enclosure?

1023.4 Openings. Interior exit stairway and ramp opening
protectives shall be in accordance with the requirements of
Section 716.
Openings in interior exit stairways and ramps other than
unprotected exterior openings shall be limited to those
required for exit access to the enclosure from normally occupied
spaces and for egress from the enclosure

 

[RLGA]

• The two exterior doors are too close together

Currently, the IBC does not require the exit discharges to be separated as required for exits. I had submitted a proposal for this code development cycle that codifies just what you stated; however, the Fire Safety Committee shot it down at the hearings in Orlando. Opponents were stating it was too restrictive. Unfortunately, I failed to mention in my testimony in front of the committee that NFPA 101 specifically requires separation of the exit discharge, so it is not something new.

 

[RLGA]

Correction: It was the Egress Committee and not the Fire Safety Committee that unanimously disapproved the proposal.

Here's a copy of what I submitted: https://www.dropbox.com/scl/fi/1sje...tion.pdf?rlkey=ctekt0bfyk0tt6pis0uwualx0&dl=0

Here's the video of the hearing from ICC on this item: https://www.cdpaccess.com/videos/6666/

 

[Paul Sweet]

It is often impossible to separate the exit discharges by 1/3 of the diagonal distance in city buildings with deep narrow buildings side-by-side.

 

[steveray]

We get some stuff right here in CT from time to time.....
1028.4.1 Remoteness
Where two or more doors leading to exit discharge are required, a minimum of two such doors shall be placed a distance apart equal to not less than one-third of the length of the maximum overall diagonal dimension of the building served, measured in a straight line between doors. Additional doors leading to exit discharge shall be arranged a reasonable distance apart so that if one becomes blocked, the others will be available.

 

[RLGA]

Well, if we can remember this discussion in three years, I am willing to work with those interested to prepare a rewrite for the next code development cycle that is more palatable to the committee.

 

[steveray]

Well, if we can remember this discussion in three years, I am willing to work with those interested to prepare a rewrite for the next code development cycle that is more palatable to the committee.

I might know a guy on the egress committee, and he loves pushing our CT stuff national...happy to help...I'll look at the videos and stuff at some point...

 

[Bergie3941]

I don't disagree that it would be a better design to have the doors further separated, though given this is a remodel and mixed use, and a historic building on top of that, we have multiple design criteria to accommodate, so I feel having some flexibility in the code as it seems there currently is, is not a bad thing. I do think I agree with Jim Gerren's comment in the video that requiring the separation seems to be over restrictive. Again, on a brand new design I would agree to keep them adequately separated, but existing conditions do apply. I appreciate everyone's input.

 

[steveray]

Agree that it is likely not require to be upgraded on a remodel....And maybe not at all anywhere but CT....