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2012 IBC Unlimited area building

pyrguy

pyrguy

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Joined
Oct 16, 2009
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472
Location
Casa Grande, AZ
507.1 General.

The area of buildings of the occupancies and configurations specified in Sections 507.1 through 507.12 shall not be limited.

Exception: Other occupancies shall be permitted in unlimited area buildings in accordance with the provisions of Section 508.2.

507.3 Sprinklered, one story.

The area of a Group B, F, M or S building no more than one story above grade plane of any construction type, ..., shall not be limited ... How are you interpreting section 507.3 for unlimited area buildings. Based on the sentance structure it would appear that you could have a group B or a group F or a group M or a group S since other sections in 507 use "and" when more than one occupancy is allowed in an unlimited area building. But there are sections in 507 that use "and" when "or" might be a better choice. The whole section 507 is inconsistent in how and/or when more than one occupancy is allowed without tripping the 507.1 Exception for "other occupancies".

I have a designer that is saying any or all of the four listed occupancies can be unlimited area in this building without tripping the 507.1 exception.

You thoughts and code sections are appreciated.
 
I'll jump in, knee jerk reaction was no, it can only be one of the four. Then upon rethinking, I don't see why not. If any of the four can be unlimited, then what does it matter if they are located under one contiguous rooftop? It will be interesting t hear other opinions.

EDIT: Now I am sitting here thinking, the reason that any of those occupncies can be unlimited area, is the separation from other buildings, if there is a fire, it will only effect that occupancy. So I am going to change my vote, I didn't want to take down my first response in case it had been seen.
 
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507.1 through 507.12 is specific to a specific use. The "other" occupancies are treated as accessory and limited to 10% under 508.2 for the uses outlined in 507.1 through 507.12

I have a designer that is saying any or all of the four listed occupancies can be unlimited area in this building without tripping the 507.1 exception.
Click to expand...
I disagree with the designer

506.5, 506.5.1 & 506.5.2 would be the charging language for determining the maximum area allowed for a mixed use building. No where does it send you to the unlimited portion like 506.4.1 exception 1 does for a single occupancy building.

508.1 seems to back this up

508.1 General.

Each portion of a building shall be individually classified in accordance with Section 302.1. Where a building contains more than one occupancy group, the building or portion thereof shall comply with the applicable provisions of Section 508.2, 508.3 or 508.4, or a combination of these sections.

507 is not mentioned
 
= ( ) =

Wouldn't Section 102.1 - General, from the `12 IBC, clarify this

[ i.e. - whichever is the "most restrictive application" ] , and

limit the Occ. type and floor square footage to 10% or less ?

= ( ) =
 
I am with FB...Think of it as mixed use non-separated.....The exceptions for "other occupancies" might be an accessory A for a cafeteria or something like that and would be allowed.....of course that is just my off the cuff opinion as well....
 
The commentary states, "Because of their excellent record in controlling and preventing fires, the installation of a sprinkler system throughout single-story buildings of the listed groups, individually or in combination, permits them to be unlimited in area (Interpretation No. 4-06)."
 
I believe an F-2 and/or S-2 would require separation from the other occupancies or be limited as accessory to the main occupancy.

In other words you can't have an unlimited mercantile use with a gypsum warehouse located in one unlimited area building.

I don't believe unlimited area buildings apply to non-separated uses unless specifically addressed in 507.2 thru 507.12

 
RLGA said:
The commentary states, "Because of their excellent record in controlling and preventing fires, the installation of a sprinkler system throughout single-story buildings of the listed groups, individually or in combination, permits them to be unlimited in area (Interpretation No. 4-06)."
Click to expand...
Then why do you only get a 1 hour reduction for sprinklers between a F-2 or S-2 and a B,M, S-1 or F-1?
 
Don't like it and don't agree with it but here is what the official interpretation is

CHAPTER 5

GENERAL BUILDING HEIGHTS AND AREAS

SECTION 507.3

IBC Interpretation No. 44-06

2003 Edition

Issued: 11-07-2006

507.3 Two story. The area of a two-story, Group B, F, M or S building shall not be limited when the building is provided with an

automatic sprinkler system in accordance with Section 903.3.1.1 throughout, and is surrounded and adjoined by public ways or yards

not less than 60 feet (18 288 mm) in width

! ! ! ! ! ! ! ! ! !

Q: Section 507.3 permits a two story unlimited area building to contain use Groups B, F, M or S. Are each of the use

Groups B, F, M or S located within the unlimited area building permitted to be unlimited in area?

A: Yes. The provisions in Section 507.3 permit all the listed use groups, or any combination of the listed use groups,

to be located within the unlimited area building. There are no area limitations for any of the use groups.

_________________________________________________________________________________________________
 
mtlogcabin said:
Then why do you only get a 1 hour reduction for sprinklers between a F-2 or S-2 and a B,M, S-1 or F-1?
Click to expand...
The building will be considered nonseparated since all occupancies in that list are considered to be of unlimited area; thus, there is no one occupancy group within that list that is more restrictive than the others. If you considered the occupancies "separated," how would you calculate the ratios with actual area to unlimited area? It can't be done. It is like determining allowable area for a mixed-occupancy Type IA building.
 
An S-2 and a B are not required to be sprinkled under Chapter 9 But they are required to have a 2 hour separation under 508.3.3

So please help me understand this better

A non-separated B and S-2 mixed use building is limited to a maximum 9,000 sq ft B and a 13,500 Sq ft S-2 type V-B construction. Exceed the sq ft limits and 508.3.3 kicks in and a 2 hour separation is required. Provide a sprinkler and reduce the separation requirement to one-hour. Provide a 60 ft surrounding yard with sprinklers and the separation goes away.

Correct?
 
That interpretation is for the 2003 IBC and a different code section, even though the section numbers match. The 2012 had sections renumbered. I have not looked at the 2003 code to see how the section is worded.

Unlimited area buildings are a different animal. 507.1 states

507.1 General.

The area of buildings of the occupancies and configurations specified in Sections 507.1 through 507.12 shall not be limited.

Exception: Other occupancies shall be permitted in unlimited area buildings in accordance with the provisions of Section 508.2.

So IF you build the building per one of the sections in 507 as listed it can have unlimited area. There are different restrictions, (60 foot clear area, fully sprinklered, occupancy class allowed, etc) placed on unlimited area buildings so that the normal area and occupancy requirements don't apply. But all other code requirements still apply just as for any other building.
 
We still amend these sections to be more restrictive....Lucky us.....!

mtlogcabin said:
Don't like it and don't agree with it but here is what the official interpretation isCHAPTER 5

GENERAL BUILDING HEIGHTS AND AREAS

SECTION 507.3

IBC Interpretation No. 44-06

2003 Edition

Issued: 11-07-2006

507.3 Two story. The area of a two-story, Group B, F, M or S building shall not be limited when the building is provided with an

automatic sprinkler system in accordance with Section 903.3.1.1 throughout, and is surrounded and adjoined by public ways or yards

not less than 60 feet (18 288 mm) in width

! ! ! ! ! ! ! ! ! !

Q: Section 507.3 permits a two story unlimited area building to contain use Groups B, F, M or S. Are each of the use

Groups B, F, M or S located within the unlimited area building permitted to be unlimited in area?

A: Yes. The provisions in Section 507.3 permit all the listed use groups, or any combination of the listed use groups,

to be located within the unlimited area building. There are no area limitations for any of the use groups.

_________________________________________________________________________________________________
Click to expand...
 
OK, bring this back up. I got a letter from the architect with the following information.

1. IIB construction type

2. A-3 occupancy classification of about 70,000 sqft being built under 2012 IBC Section 507.? for unlimited area A-3 buildings

3. total building area of 1,500,000 sqft.

4. other occupancies proposed are M, B, S-1, and A-2.

They are trying to use 507 for A-3 occupancy classification unlimited area building without using the exception for "other occupancies" that restricts the area for these other occupancies. Sorry I am at home and don't have the exact code sections.

Does this change any body's mind?
 
pyrguy said:
OK, bring this back up. I got a letter from the architect with the following information.1. IIB construction type

2. A-3 occupancy classification of about 70,000 sqft being built under 2012 IBC Section 507.? for unlimited area A-3 buildings

3. total building area of 1,500,000 sqft.

4. other occupancies proposed are M, B, S-1, and A-2.

They are trying to use 507 for A-3 occupancy classification unlimited area building without using the exception for "other occupancies" that restricts the area for these other occupancies. Sorry I am at home and don't have the exact code sections.

Does this change any body's mind?
Click to expand...
I would say this is acceptable; BUT, the Group A-3 would be limited to 9,500 sq. ft. and not the 70,000 sq. ft. mentioned.



If Section 507.3 is used for the Group B, M, and S-1, and the Group A-2 is included per Section 507.3.1, then the Group A-3 may be included as an accessory occupancy per the exception to Section 507.1. The problem is that Section 508.2.1 limits the area for accessory occupancies to the tabular areas in Table 503 WITHOUT increases.

So, even though the Group A-3 does not exceed 10% of the floor area in which it is located, it does exceed the tabular area and would not be permitted with an area of 70,000 sq. ft.

Trying to use the unlimited area provisions in one section for the Group A-3 (i.e. Section 507.6) with the unlimited area provisions in another section (i.e. Section 507.3) would not be allowed. I believe the intent, as stated in theCommentary, is limited to the occupancies and combinations provided in this section.
 
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