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.