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Building too large for Type of Construction

Young Architect

Registered User
Joined
Oct 28, 2020
Messages
4
Location
Washington DC
As I was researching an existing building's Type of Construction. I think it is most likely a type II-B classification (I still need to do some site investigation to confirm) From photos it is steel structure with no fire proofing. If I reference the allowable sq/ft under Type II-B construction, I realized that the existing building is over what is allowed in the current code (currently around 97,000sq/ft). Is there some exception I can reference for this particular issue? I am not adding any sq/ft... I am also trying to search through IBC if there is any exception to Type II-A construction where the primary structure would not need to be 1 hour rated...

I want to add some conference rooms and a break area. The existing area is open office / private offices - not increasing the building sq/ft.
The building is equipped throughout with automatic sprinkler system. 2 stories. Currently Business occupancy and I would not change.

This building was originally built in the 1980's. I am a little perplexed how to handle this situation. I am sure there is a way to make the planned alterations without needing to add fire proofing on the existing structure. Maybe I am misunderstanding something with the fire rating requirements?

Also curious what the best way to show this information is on the code sheet of the drawing set that will be turned in for review...? Should I bring any attention to it? Or just list it as a type II-B construction with the sq/ft of the building (even though the sq/ft is over what is allowed) and call it a day?

Referencing IBC 2015
 

cda

Sawhorse 123
Joined
Oct 19, 2009
Messages
19,058
Location
Basement
Welcome

I am not into area,

1. This building was originally built in the 1980's,,, May be your first clue.

2. you would need to know what code it was built under and year edition.

3. If you are going by current code, did you add all the allowable increases

4. Most of the time, it is taken the building met code when built

5. Since not adding to the building, maybe just represent all materials to be used are allowed in this type building, per adopted code.

Give it a few days for more answers
 

classicT

Sawhorse
Joined
Aug 2, 2017
Messages
1,589
Location
Washington State
As suggested by others, follow the IEBC. Being that there is not a change of use, you really should have no issue.

If IEBC is not adopted, and AHJ requires that you meet the IBC, can it meet IBC Section 507.5?

507.5 Two-Story Buildings
The area of a Group B, F, M or S building no more than two stories above grade plane shall not be limited where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 and is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.
 

lifesafetyinfo

Registered User
Joined
Sep 18, 2020
Messages
9
Location
Pittsburgh, PA
I agree with the others - follow the IEBC path. If you're not changing the use, and not expanding the area then you should be OK as it is right now - especially if it's already sprinklered. If you add even one square foot, then the addition would kick you over the area limitation:

1102.2 Area limitations. No addition shall increase the area of an existing building beyond that permitted under that permitted under the applicable provisions of Chapter 5 of the International Building Code for new buildings unless fire separation as required by the International Building Code is provided. (2015 IEBC)
 

Paul Sweet

Sawhorse
Joined
Oct 17, 2009
Messages
1,417
Location
Richmond, VA
Is the 97,000 SF the total area of both floors, or is it the footprint? The allowable area(s) in Table 506 are for the largest story.

RANT - I can't believe how the ICC screwed up the height & area tables. I've been using them since the 1975 BOCA code, and have never had trouble understanding them and doing the equations until now!
 

Tim Mailloux

Registered User
Joined
Feb 12, 2018
Messages
392
Location
Hartford CT
Is the 97,000 SF the total area of both floors, or is it the footprint? The allowable area(s) in Table 506 are for the largest story.

RANT - I can't believe how the ICC screwed up the height & area tables. I've been using them since the 1975 BOCA code, and have never had trouble understanding them and doing the equations until now!
the tables are fine, its the new equations that are stupid.
 
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