Exit passageway - cross corridors

[nealderidder]

Attached is a ground floor plan of a five story building that has a feature that's become almost a standard for me. The project includes three other buildings, they all have this same exit passageway arrangement and they've all been permitted. I used a well know code consulting firm on this project and they assure me this is allowed. But it always seemed a bit off to me. Do any of you have a problem with it? "It" being the two doors opening into the passageway from the cross corridor.

This is a 5-story office building in CA under the 2019 code. As you can see we've got two interior exit stairs. One passes thru the lobby the other reaches the exterior with an exit passageway. My question is about the corridor that crosses the exit passageway. Two doors from the cross-corridor open into the passageway. Both swing into the passageway making them look like someone from the service area could exit into and thru the passageway and the same for someone from the lobby. But we all know the main purpose for those doors is to move bodies from the front of the building to the back.

Maybe the last few words of CBC 1024.1 "An exit passageway shall not be used for any purposed other than a means of egress and a circulation path." allow this?

From 1024.5 "openings shall be limited to those necessary for exit access to the exit passageway from normally occupied spaces and for egress from the exit passageway."

Do any of you take issue with what you see here?

Thanks for your time.

 

[RLGA]

I see no problem with it.

What you call a "cross-corridor" appears to be an exit passageway and not a corridor since it has a 2-hour rating (assuming I am interpreting the wall symbol correctly).

An exit passageway does not have to be solely dedicated to egress as you pointed out in Section 1024.1, much like stairways. Section 1023.1 (2019 CBC) for stairways states an "interior exit stairway or ramp shall not be used for any purpose other than a means of egress and a circulation path."

As for Section 1024.5, I do not see any opening that does not comply with this section--all doorways lead from occupied spaces or egress from the exit passageway. There are no doors into storage or mechanical spaces, nor are there any windows.

 

[nealderidder]

Hi Ron,

What I'm calling the "cross corridor" is the corridor running from the front-of-house to back-of-house that's perp to the exit passageway and intersects it. I guess it feels off because that corridor and the openings to it aren't really there to get into the exit passageway (although they do that too), they are there to get from the front to the back. But like you said, 1024.1 allows the passageway to serve as a "circulation path" so I guess that's the trump card.

A follow up question. If I add a few floors here and become a high-rise, does anything change? I'm thinking of stair pressurization and smoke control. Would this ground floor plan still be viable? A high rise and pressurization will add vestibules to my stairs at upper levels, what about at the ground floor?

 

[RLGA]

Hi Ron,

What I'm calling the "cross corridor" is the corridor running from the front-of-house to back-of-house that's perp to the exit passageway and intersects it. I guess it feels off because that corridor and the openings to it aren't really there to get into the exit passageway (although they do that too), they are there to get from the front to the back. But like you said, 1024.1 allows the passageway to serve as a "circulation path" so I guess that's the trump card.

A follow up question. If I add a few floors here and become a high-rise, does anything change? I'm thinking of stair pressurization and smoke control. Would this ground floor plan still be viable? A high rise and pressurization will add vestibules to my stairs at upper levels, what about at the ground floor?

That is not a corridor it is an exit passageway (see shaded area) in the attachment. I do not think it is necessary to extend the exit passageway this far towards the lobby, but there is nothing wrong with it. I am not sure Door #3122A is necessary, but it could keep those coming down the stairs from accidentally going down that portion of the exit passageway. There are only three doors into the exit passageway: 31ST2, 3127, and 3122C. And there is only one door out of the exit passageway to the exterior: 3122B.

Every area has access to at least two means of egress. I was concerned about the separation of exit access doors for Tenant Space 3130A, but they are at least 1/3 the overall diagonal (but barely--5 inches to spare).

As for high-rise applications, you have two options: a smokeproof enclosure with mechanical ventilation per Section 909.20.4 (natural ventilation is not possible with that stair arrangement) or pressurization per Section 909.20.5. A vestibule is required for the mechanical ventilation option but is not required for the pressurization option.

 

[nealderidder]

Thank for the follow up Ron. I see what you mean about the corridor between doors 3127 and 3122A - certainly looks like an exit passageway but I'm not sure why we did that. I don't see the need for the two hour rating for those corridor walls.

You mentioned high rise options:

Mechanical Ventilation per 909.20.4

or

Pressurization per 909.20.5

In CA 909.20.4 is the Mechanical pressurization alternative. My code consultant tells me that in a high rise my ground floor exit passageway can have what I keep calling the cross-corridor doors into it per CBC 1023.11 Exception #1. But this exception requires that the exit passageway is protected and pressurized in the same manner as the smokeproof enclosure, and openings are protected as required for access from other floors... Per my consultant, this means a vestibule is required for the exit passageway just like it is for the upper level stairs if I want to pop those doors in there. Something like the attached. Which is a drag because it's pinching my elevator access but I think I can nudge the elevators north and be OK.

Thanks for the input as always!