Table 602 and Mixed Occupancies

[RLGA]

I couldn't find another thread on this subject, so I thought I'd start one.

Neither the IBC nor its Commentary address the application of Table 602 to a mixed occupancy building. I'd like to know what your thoughts are and how you apply or interpret this table for such an application.

Assume IIB construction and 4-foot fire separation distance. Building includes Groups M and A-3.

Do you:

1. Use a 2-hour exterior wall because the building contains a Group M?

2. See which occupancy the exterior wall is adjacent to and use either a 1-hour or 2-hour exterior wall as applicable?

3. Other interpretations?

Now, let's assume the building is two stories with the Group A-3 on the 2nd story which overhangs the Group M on the 1st story. The wall of the 2nd story has a fire separation distance of 4 feet and the wall of the 1st story has a 10-foot fire separation distance (i.e. 2nd story overhangs the 1st story by 6 feet).

Do you:

1. Use a 2-hour exterior wall at the 1st and 2nd stories because the building contains a Group M?

2. Use a 1-hour exterior wall at the 2nd story for the Group A-3 and no rating at the 1st story for the Group M?

3. Other interpretations?

Thanks!

 

[Codegeek]

For the mixed occupancy, if it is nonseparated uses, then I would use Table 602 based on the most restrictive use for which the building has been designed. The IBC Commentary indicates that once the occupancy classification has been determined, then Table 602 is applied. Since the A-3 use is more restrictive in terms of area, then I would assume the entire building to be an A-3 occupancy and use Table 602 as such.

If the uses are not separated, then I would use the table based on the location of the use to the property line.

 

[RLGA]

Codegeek:

I like your logic, but your last sentence confuses me.

Since the first paragraph talks about nonseparated uses and your last sentence mentions "uses [that] are not separated," this appears to be the same thing but two different applications.

Did you mean to say in the last sentence, "If uses are separated..."?

 

[RLGA]

Codegeek:

In reviewing Section 508.3 (2012 IBC) for nonseparated occupancies, Section 508.3.1 states, in part, the following:

"The requirements of this code shall apply to each portion of the building based on the occupancy classification of that space. In addition, the most restrictive provisions of Chapter 9 which apply to the nonseparated occupancies shall apply to the total nonseparated occupancy area."

Section 508.4 for separated occupancies has a similar requirement in Section 508.4.1.

In an indirect way, I interpret this to mean that the #2 responses in my original post would be the appropriate response to ech situation indicatd.

Would others agree?

 

[Codegeek]

Codegeek:I like your logic, but your last sentence confuses me.

Since the first paragraph talks about nonseparated uses and your last sentence mentions "uses [that] are not separated," this appears to be the same thing but two different applications.

Did you mean to say in the last sentence, "If uses are separated..."?

Yes, my apologies. And to the last post, if the uses are separated, then yes, I would say that your response #2 would apply.

 

[brudgers]

2. Use a 1-hour exterior wall at the 2nd story for the Group A-3 and no rating at the 1st story for the Group M?

I will just assume that either you were making a joke, or didn't proof read what you were writing.

 

[Markmax33]

I would use the most restrictive for non-sep and use whatever the occupancy is for separated use for the corresponding wall.