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Code struggle on business/industrial building

  • 1.  Code struggle on business/industrial building

    Posted 08-18-2020 08:15
    I'm doing an addition to an existing light industrial building. Butler style building, with the typical warehouse side (in this case, vehicle repair) and offices boxed out inside a portion of the building. Like many of these buildings, they are using the ceiling of the offices as additional space - some of it is open mezzanine to the vehicle warehouse below, and there are some boxed out offices as a 2nd story. This upper area is too large to be a "mezzanine" so it's an official 2nd story. There's no need to separate the two occupancies (S-1 and B) and the building does have sprinklers.

    We are adding onto this building, the addition will have a real 2nd story, which will connect back to this wonky hybrid of offices and mezzanine. (When I say mezzanine, I mean it's open to the level below). Access from the offices / mezzanine is partly at an enclosed stair, and also has 2 stairs that are wide open to the warehouse/vehicle repair level below.

    I'm struggling with the code review since this upper level isn't separated from the level below (open exit access stairs plus the open "mezzanine").

    Can someone check me? I'm reading that (2015 IBC) 712.1.9 Two-Story Openings are allowed (which should allow the mezzanine to be open, no need to separate the levels) and 1019.3 Occupancies Other Than Groups I-2 and I-3 exception 1 allows exit access stairs to be open. As long as my travel distances work (all the way down the stairs to the exit door), do you think I have any glaring code issues? I do note that this means multiple exit access stairs open to the level below, any issues with this?

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    David Sisson AIA
    Architect
    David Sisson
    Providence RI
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  • 2.  RE: Code struggle on business/industrial building

    Posted 08-19-2020 18:20
    Edited by Bruce Rose 08-19-2020 18:30
    David,
    I agree with your reading.  I've designed a number of buildings similar to the one you describe, and never had an issue with separation because of the communicating levels. It is similar to a 2-story lobby in an office building for example. The key is that you're dealing with a two story building, and I believe the salient code language is 712.1.9 as you mentioned.  Note that the clause says you must comply with ALL of the 6 items listed.  One caveat I can think of would be ventilation because of the motor vehicle repair occupancy.  Look at 406.8.2, and if you have an MEP engineer, discuss how the ventilation of the garage needs to be separated from the rest of the building.  (But that isn't a code separation like you are thinking of, just a necessary HVAC move.)

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    Bruce Rose
    Owner/Architect
    Rose Design
    Mansfield TX
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  • 3.  RE: Code struggle on business/industrial building

    Posted 08-19-2020 18:44
    David,
    From what you have written, it sounds fine. You are allowed one open stair from a second floor. No code official will frown on more exit stairs.
    Check your total height and area as a two story building - with existing and new added together. Then you can see if you need to separate the new from the existing (for fire areas or with fire wall).
    If you are primarily doing the addition (with little work in the existing and maybe not relying on the existing for egress from the new), then you can look in the Existing Building Code for justification that you are not making anything in the existing building less safe than it currently is.
    And even though it looks like a mezzanine, if it does not qualify then it is not advisable to use that term when speaking about this building or writing up your Code Information for the permit documents. It can cause problems and misunderstandings.

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    Neena Jud AIA
    Architect
    Harmony Architecture
    Cincinnati OH
    ------------------------------

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  • 4.  RE: Code struggle on business/industrial building

    Posted 08-19-2020 20:41
    David,

    I didn't read your post carefully enough.  I believe that you need two enclosed stairs, in addition to any (open) exit access stairs.  If you read the definition of "exit access stairway" and "interior exit stairway" in Ch. 2 you will see that only the interior exit stairway definition reads that it can be counted toward design requirements such as the number of required exits. I assume you have enough occupants upstairs that you need at least two means of egress, so it sounds as if you may need to enclose one of the open stairs, or create an additional new stair somewhere to achieve two enclosed stairs.

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    Bruce Rose
    Owner/Architect
    Rose Design
    Mansfield TX
    ------------------------------

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  • 5.  RE: Code struggle on business/industrial building

    Posted 08-20-2020 09:11
    Bruce, I'm seeing:

    Table 1006.3.1 requires 2 EXITS or ACCESS TO EXITS from a 2nd story. An unenclosed stair is an "exit ACCESS stair" and you are right, it is not an "exit" itself per the definitions in chapter 2.

    Since 1019.3 allows open "exit access stairs" to connect 2 levels - do I even need 1 enclosed "interior exit stair"?

    Of course, this is all dependant on meeting travel distances from any point on the 2nd floor to the exit door on the 1st floor.

    In a broad sense, what I'm reading is that smaller 2 story buildings don't need any enclosed stairs as long as they meet travel distances, and are sprinkled. (and are not certain use categories).

    Do you think I have the correct code read?

    ------------------------------
    David Sisson AIA
    Architect
    David Sisson
    Providence RI
    ------------------------------

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  • 6.  RE: Code struggle on business/industrial building

    Posted 08-20-2020 10:53
    David,
    You definitely raise an interesting point.  I think the best course of action at this point (since you've done your homework) is to have a discussion with the AHJ.  Their opinion is the only one that counts.  I always try to go into a discussion with them armed with the code language in front of me, since they are human too, and can sometimes forget a relevant code provision that might ease restrictions.  Please let us know how it turns out.  I would think this is a relevant question for many people in this forum.

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    Bruce Rose
    Owner/Architect
    Rose Design
    Mansfield TX
    ------------------------------

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  • 7.  RE: Code struggle on business/industrial building

    Posted 08-22-2020 09:32
    It seems you did your homework thoroughly and it sounds like it should work.  I agree with Bruce that it's time to have a meeting with the AHJ to make sure they are in agreement with your analysis.  I also strongly second Neena's suggestion to avoid mentioning "mezzanine" in the conversation.  Mezzanines are odd ducks and come with a risk of triggering the conversation towards unproductive directions.

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    Justus Pang
    Nevada State Public Works Division
    Las Vegas NV
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