Exit Discharge Through Non-rated Lobby

[nealderidder]

I know, an oldie but a goodie. Probably gets posted here once a year at least. I think my trepidation is that it really feels like a lobby should have a fire separation but 1028.1 tells me something else.

Consider a four story office building in California. Two interior exit stairs, one leads directly to the exterior via an exit passageway, the other travels through a lobby (see attached). Lobby is at discharge level and is on grade (nothing below it). Fully sprinkled NFPA 13.

Per 1028.1 Exception 1 the lobby is not required to be separated from the rest of the building just because this stair discharges into it. So in the future if I have new tenants on either side of the lobby they could put new entrances in (think storefront) without worrying about the demising wall being fire rated. Right?

Here's the tricky part. Put in some seating areas and the lobby will probably get called an "A" occupancy by the AHJ. Is that where I'll be required to rate that wall? Because it's an "A" on the lobby side and a "B" on the tenant side?

Can you think of any other situation (ignoring non-sprinkled option) where I would need those walls between lobby and tenant to be rated?


Thanks!

 

[mtlogcabin]

Is it an exit access stairway or an interior exit stairway?

I suggest you read IBC Section 1028.1 and the exceptions and see if the design complies. CA may be different

 

[steveray]

Form that plan, this gets arguable:

1.1. Discharge of interior exit stairways and ramps shall be provided with a free and unobstructed path of travel to an exterior exit door and such exit is readily visible and identifiable from the point of termination of the enclosure.

There is nothing outright in the the code that says A must be separated from B....A code analysis would need to be performed...

 

[classicT]

Separation of occupancies would only be required if you are using mixed use separated per 508.4. Otherwise, no separation is required.

And as Steveray said, I agree that the this plan does not appear to have an exit that is readily visible and identifiable from the point of termination of the enclosure. (1028.1, 1.1).

This is commonly interpreted as meaning a direct line of sight from the door threshold to the exit. Appears to be questionable in this plan.

 

[nealderidder]

Is it an exit access stairway or an interior exit stairway?

I suggest you read IBC Section 1028.1 and the exceptions and see if the design complies. CA may be different

It's an interior exit stair. I do believe I qualify for the exceptions (no space below, bldg sprinkled etc.).

 

[nealderidder]

Separation of occupancies would only be required if you are using mixed use separated per 508.4. Otherwise, no separation is required.

And as Steveray said, I agree that the this plan does not appear to have an exit that is readily visible and identifiable from the point of termination of the enclosure. (1028.1, 1.1).

This is commonly interpreted as meaning a direct line of sight from the door threshold to the exit. Appears to be questionable in this plan.

I think I've got my answer regarding the separations, it's as I suspected, only required if an occupancy sep is required. Interesting comment about the visibility of the exit... Sounds like you're saying a direct line of sight from threshold to exit does not meet the requirement for visible and identifiable from the point of termination of the enclosure? I know I've gotten away with a similar layout in the past. Depends on the reviewer I suppose. I can't imagine anyone would just freeze at that threshold and not be able to find the lobby exit... Thanks for the input!

 

[classicT]

Sounds like you're saying a direct line of sight from threshold to exit does not meet the requirement for visible and identifiable from the point of termination of the enclosure?

Apologies, that was not the intent. What I was trying to indicate is that by looking at the plan you posted, I do not believe that a direct line of sight exists from the point of termination of the enclosure (the door threshold) to the exit (exterior door). Meaning, I do not believe that your plan explicitly complies. Not saying that it is a solid case, but it will be up to the AHJ reviewing it to make that determination.

 

[Paul Sweet]

Could you angle the wall in front of the door from the stairs to open up the line of sight?

 

[nealderidder]

I think what we'll wind up doing is bringing the stair door out to the main lobby wall.

 

[nmonday]

I think what we'll wind up doing is bringing the stair door out to the main lobby wall.



View attachment 8435

I have a similar situation - but with a vestibule at the exterior doors. Do I need to provide an exit only door somewhere along that curtain wall in addition to the vestibule that would be located at the double doors you currently have shown? Basically, is there any issue having the occupants leaving the stair to have to travel through the lobby... and THEN through a vestibule?

 

[steveray]

I wouldn't get too critical of a vestibule....

 

[nmonday]

I am starting to think a vestibule would be a problem now that I took a look at the commentary regarding 1028.1 exception 2 where the stair exits directly into a vestibule.

 

[steveray]

Is it a 50sqft vestibule or a 1000sqft vestibule? Makes a difference....

 

[nmonday]

Is it a 50sqft vestibule or a 1000sqft vestibule? Makes a difference....

75sqft

 

[steveray]

I would guess the exterior vestibule would not violate the spirit of the " visible and identifiable from the point of termination of the enclosure."

If you make it into that vestibule you are effectively out of the building, but details and AHJ interpretation matter...

 

[Mr. Inspector]

Is there a reason that the whole lobby can't be a vestibule? I don't see any maximum size for a vestibule or even a definition in the 2015 codes. Odd that the IECC has the "vestibule definition" only in the index of the residential part of the IECC which sends you to the definition chapter, but the definition is missing.