Atriums in the IEBC

[Sifu]

I have a building with an existing 4-story open atrium (un-separated on all 4 stories). Not sure how it got there. T/I proposals for a remodel of a space adjacent to the atrium do not include 1-hr fire barriers or alternative glazing systems or rated opening protectives. Sprinklers and smoke control are provided but the exception in 404.6 stops at three connected floors.

In a nutshell I am trying to figure out how the DP has arrived at the conclusion that this is approved. (I asked them but they said they would have to call me back.) I don't think it is permitted in the IBC but I have so little experience with the IEBC I don't know for sure about it and I still need help!

Option #1: Using the IBC for the new tenant space, we would require compliance with 404, which includes atrium separation for the work area for that single tenant space.

Option #2: For an IEBC prescriptive compliance method, the code says that alterations must comply with the IBC, so that takes me back to option #1. However it also says that the existing building can be no less compliant than it was before the alteration. I read this to mean that in the course of the T/I scope, we don't look at the fact that the atrium is not separated beyond the scope of the tenant space. In other words, we do not increase the scope of work, we only enforce the separation for those areas covered by the T/I scope. Agree or disagree?

Option #3: For a level 2 alteration the way I read 802.2.1 (2018) the only way to have an un-enclosed atrium connecting 4 stories is if they comply with IEBC 802.2.1 exception 3 et al. Agree or disagree? In this case the space would not comply since #3.2.3 is not met (the building is carved up and a maze beyond the atrium).

In all cases I conclude that even though we can't retroactively require the atrium enclosure for the entire building be restored, we can require the tenant space to restore their portion of the enclosure. Agree or disagree? Have I missed an option?

 

[Sifu]

Should have noted that for the sake of this discussion the performance path is not under consideration and would be the last resort.

 

[mtlogcabin]

Not sure how it got there.

That is the first question that needs to be answered. If it was "legal" at the time it was built then you may not be able to require anything.
This is the DP's problem to prove it was legal at the time it was built not yours.

 

[Sifu]

Yes, it has been put back on them. Built under the UBC, which as far as I know always required the enclosures for atriums greater than 3 connecting stories (I think 1982 is the first atrium mention) and before that they were considered shafts and code was even more restrictive. I am going through this because of the downward pressure from management on calls such as these. This is an exercise in covering my own arse and being able to speak to their question of "how did it get this way if it wasn't allowed......therefore it must have been allowed!?" And because I want to learn the IEBC to see where it can help with conditions such as these.

A little more background. I did 3 permits in this building last year, and when I got these I saw this issue and remembered thinking about this back then. I asked myself how could I have approved the permits last year. I was able to find the plans (all 3) and they claimed that the building only had 3 communicating atrium levels, and I approved them based on that. I got suspicious so I visited the building and found that they have 4 communicating levels. So the 3 permits they have open are in question, as well as all of the new ones.

 

[steveray]

Seems like you are on the right path with 802.2.1