Existing Building Analysis per Chapter 34

[ETThompson]

Hi

Does anyone have experience or insight with calculating the area value "i" in the old version of the existing buildings code, Chapter 34? (3412.6.2.2 Area formula / Equation 34-4)

https://up.codes/viewer/ohio/ibc-2015/chapter/new_34/existing-buildings-and-structures#new_34

Ohio has not adopted the IEBC.

First some context on our project.

We are renovating and adding to a complex of two existing buildings. The project is a dance academy and Performance space. Our addition will connect the two, so we'll have one continuous complex when done. Both the existing and the new will be Type IIIB construction. See attached rough sketch.

We are modifying the north wall of one of the buildings to be a Fire Barrier, in order to meet the area requirements outlined in 3412.2.3.2.2. The area north of the Fire Barrier has A-1, A-3, S-1 and F-1 occupancies. The area south has B, F-1 and S-1 occupancies.

Where we are adding new walls in the existing buildings, we are constructing them as required per 508.4. Up til now, we have not planned to separate the existing walls, although we could if needed.

My questions:

1. In the first "allowable area i", would this be for the overall project (therefore, taking worst case, A-1 at 9,500)? If not, what?

2. For the first part of the remaining formula, is the "actual area i" divided by "allowable area i" any occupancy that is separated per 508.4?

3. What values do I use for "actual area n" divided by "allowable area n"? "n" is "Number of separated occupancies on a floor" but I'm not clear what values I would actually use here. Or is this just the last in the series of separated occupanices?

4. Finally, how do I count occupancies that are not separated but are also not required to be separated? For example, in our south/bottom existing building, there is a Scene Shop (F-1) and a Costume Storage (S-1) which are not separated currently from the overall B. Do I have to use the 'worst case' allowable area for one of these and apply it to the overall B square footage? That doesn't seem right if I'm not required to separate.

Any help that can be given would be much appreciated.

Thanks

 

[BillS]

I’ve found the commentary sections for this specific situation immensely valuable...:

If there are multiple occupancies on a story (separated or not), you’ll need to create a separate scorecard for each occupancy.

If an occupancy is located on more than one story, a separate Area Value i must also be calculated for each story, and the value used in the final table i the lesser of all the individual area values.

For the remainder of the equation, this is where separate occupancies get involved... if there’s no separated occupancies than the numerator for each fraction is 0 and gets eliminated but for any separated occupancy the fraction of its Actual Area/Allowable area is included here.

Hope that helps clarify what is often a complex formula.

 

[ETThompson]

Thanks for the info. I wasn't sure there was a commentary, but will look into getting that. I did eventually figure it that we either met all the separations required by 508.4 or didn't need a separation, so did each occupancy individually. It took forever, but I think it worked! Thanks for your help.