Chapter 34 - Mixed Occupancies

[Modamerican]

I need some help clarifying some of the language in section 3412.6.16 Mixed Occupancies. I have an existing building that has mixed occupancies. It has business occupancy on the 1st floor and r-2 on the 2nd floor. The floor between them is not a rated assembly.
Here is the section from the code.
https://up.codes/viewer/ohio/ibc-2015/chapter/new_34/existing-buildings-and-structures#new_3412.6.16
The following line is were I'm getting hung up.
Where there is no separation between the mixed occupancies or the separation between mixed occupancies does not qualify for any of the categories indicated in Section 3412.6.16.1, the building shall be evaluated as indicated in Section 3412.6 and the value for mixed occupancies shall be zero.
Based on the way I'm reading this my value would be "0". That doesn't seem logical to me. If my building qualified for category 'a' my value would have a value of "-10" even thought that is a safer condition not separation? Am I miss reading this?
Thanks in advance for your insight.
David

 

[cda]

Welcome

 

[cda]

Not an existing chapter person,

Give it a few days for great replies

So you have an existing building, with this condition.

What is your real question??

What are you trying to do???

 

[cda]

I am thinking the building needs a seperation,,,

Or in some mixed, the entire building has to be built to more stringent of the two occupancies.

 

[RLGA]

The paragraph states that if you do not qualify for either of the categories, then you get no points and now have to evaluate for each occupancy group in the building per Section 3412.6, and the occupancy group with the lowest score for each section is used for the entire building. So, for your situation, you need to evaluate the entire building as if it were a Group B, and then evaluate it as if it were a Group R-2 building. The score that is the lowest for each section is then used for the entire building.

For example, look at Section 3412.6.4 on corridor walls. If your building is Category 'a,' then for Group B the score is -5, and for Group R the score is -7. Since Group R has the lowest score, you have to use -7 for the building score. In your situation, I would expect that every section would have a score for Group R that is lower than that for Group B; however, that is not necessarily the case for other mixes of occupancy groups.

 

[Modamerican]

The paragraph states that if you do not qualify for either of the categories, then you get no points and now have to evaluate for each occupancy group in the building per Section 3412.6, and the occupancy group with the lowest score for each section is used for the entire building. So, for your situation, you need to evaluate the entire building as if it were a Group B, and then evaluate it as if it were a Group R-2 building. The score that is the lowest for each section is then used for the entire building.

For example, look at Section 3412.6.4 on corridor walls. If your building is Category 'a,' then for Group B the score is -5, and for Group R the score is -7. Since Group R has the lowest score, you have to use -7 for the building score. In your situation, I would expect that every section would have a score for Group R that is lower than that for Group B; however, that is not necessarily the case for other mixes of occupancy groups.

Ok Great.... Thanks for verifying. That's the way I did it. Chapter 34 can be a little overwhelming. By the time I got to the end of the review I was 2nd guessing everything.
Thanks again.
David

 

[cda]

Ok Great.... Thanks for verifying. That's the way I did it. Chapter 34 can be a little overwhelming. By the time I got to the end of the review I was 2nd guessing everything.
Thanks again.
David

Welcome to the wide wide world of Codes.

Keep on coming back to ask and answer questions

 

[cda]

Ok Great.... Thanks for verifying. That's the way I did it. Chapter 34 can be a little overwhelming. By the time I got to the end of the review I was 2nd guessing everything.
Thanks again.
David

A good book to have in the library

Amazon.com: Applying the Building Code: Step-by-Step Guidance for Design and Building Professionals (Building Codes Illustrated): 9781118920756: Geren, Ronald L.: Books

Amazon.com: Applying the Building Code: Step-by-Step Guidance for Design and Building Professionals (Building Codes Illustrated): 9781118920756: Geren, Ronald L.: Books

www.amazon.com