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existing unlimited area building question.

rktect 1

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Oct 20, 2009
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Location
Illinois
There is an existing, built to 1984 and 1996 BOCA, unlimited area building mixed use B/F-1. One side of the building has 3 hour rated wall due to proximity to property line, about 35-40 feet. Sprinklered. Type 2C and around 140,000 sq. ft.

The factory has downsized and a permit is in for 75,000 sq. ft. of this space for an A-3 gymnasium with a raised floor over at least 10,000 sq. ft., maybe 5-6 feet above finished floor.

Per 2006 IBC it now requires a 60 foot separation to remain unlimited area but again they only have 35-40 on one side. Plus the A-3 has its own issues in section 507.6 especially with this raised platform/finished floor. The definition of a platform does not include height, except in section 410.4 where frtw is allowed under 30 inches.

So is this a floor or platform? because it is A-3, all exits require ramps to exits? What about #3 of section 507.6 where assembly floor shall be located at or within 21 inches of street grade level? And of course the building is currently BOCA unlimited but IBC not so much without the 60 foot public way?
 
Looks like a great opportunity for a FPE to develop an alternate approach for approval. I do not see any fundamental issues that cannot be accomodated. The details need to be worked out for the alternate.
 
Without knowing the building's current construction type classification, there is no way to determine if it can comply with all the requirements.

However, firewalls are clearly an option.
 
brudgers said:
Without knowing the building's current construction type classification, there is no way to determine if it can comply with all the requirements. However, firewalls are clearly an option.
That would be my design solution. But I am not allowed to design, only write review comments for the submitted plans, and leave the solution to the architect. Once the fire wall goes in between the F-1 and A-3 and it is no longer an unlimited area building, they seem like they would be ok.

edited:
 
Last edited by a moderator:
On a side note.

It would have been nice had the architect provided me all this information about the building to begin with. I'm lucky we have everything archived in house.
 
That would be my design solution. But I am not allowed to design, only write review comments for the submitted plans, and leave the solution to the architect.
You can discuss viable alternatives with the architect, who can take them or leave them knowing that alternatives or appeals could extend the time it takes to gain approval. Telling an architect that fire walls are a solution is not designing.
 
permitguy said:
You can discuss viable alternatives with the architect, who can take them or leave them knowing that alternatives or appeals could extend the time it takes to gain approval. Telling an architect that fire walls are a solution is not designing.
Absolutely - there is nothing in the code that says you can't talk to the DP, or anyone else, for that matter.
 
Fire Walls could void the original code strategy of unlimited area with clear space around the perimeter. A true fire wall in an existing building would be very difficult and would not add much to the life safety features of the building.
 
The A-3 is a real issue on the one side. It may need to be carved into two buildings via fire wall(s). They would not be happy at that point.
 
I'm having trouble figuring out why they want the raised area? It's obviously going to create a lot of code issues and expense (including additional sprinklers under it). Have they provided any information of its use?
 
What is putting a fire wall into an existing building really going to accomplish? B, F and A-3 are all allowed unlimited area (a property issue). A-3 has access to grade requirements (a life safety issue). In an existing building, you should be able to reasonably accomodate the new tenant despite reduced clear space (a property issue)
 
Msradell said:
I'm having trouble figuring out why they want the raised area? It's obviously going to create a lot of code issues and expense (including additional sprinklers under it). Have they provided any information of its use?
Oh, THEY don't want sprinklers.
 
Coug Dad said:
What is putting a fire wall into an existing building really going to accomplish? B, F and A-3 are all allowed unlimited area (a property issue). A-3 has access to grade requirements (a life safety issue). In an existing building, you should be able to reasonably accomodate the new tenant despite reduced clear space (a property issue)
Did you read the four listed criteria for unlimited area A-3?
 
rktect 1 said:
Did you read the four listed criteria for unlimited area A-3?[/QUOTNo stage - life safety

sprinklers - life safety and property

21 inches to grade with ramp - life safety

60 foot separation - property

If you can meet all of the life safety provisions, surely and alternate case can be made for the 60 foot separation.
 
Coug Dad said:
rktect 1 said:
Did you read the four listed criteria for unlimited area A-3?[/QUOTNo stage - life safety

sprinklers - life safety and property

21 inches to grade with ramp - life safety

60 foot separation - property

If you can meet all of the life safety provisions, surely and alternate case can be made for the 60 foot separation.
Honestly, I can give them the 60 foot separation because under the 1996 BOCA it allowed the A-3 unlimited area with the same criteria as the F-1 which is the 3 hr rated wall. But the 5-6 foot tall 10,000 sq. ft. platform was not designed and installed under BOCA. This is currently an F-1 use. So, either they need to find a way out of unlimited area to allow the platform or lower the platform, which they will not do.
 
rktect 1 said:
Coug Dad said:
Honestly, I can give them the 60 foot separation because under the 1996 BOCA it allowed the A-3 unlimited area with the same criteria as the F-1 which is the 3 hr rated wall. But the 5-6 foot tall 10,000 sq. ft. platform was not designed and installed under BOCA. This is currently an F-1 use. So, either they need to find a way out of unlimited area to allow the platform or lower the platform, which they will not do.
How about that minor detail of them not wanting to provide sprinklers?
 
Coug Dad said:
Missed that little additon about not wanting sprinklers. FAIL!
Sorry, I was trying to quote rktects post #16, and for some reason your quote within his post is the only thing that showed up.
 
Coug Dad said:
Fire Walls could void the original code strategy of unlimited area with clear space around the perimeter. A true fire wall in an existing building would be very difficult and would not add much to the life safety features of the building.
If they want to get the intended occupancy [A3] into the building, then they can widen the clear space around the perimeter [and possibly upgrade construction] or install fire walls [thereby abandoning they unlimited area building]. You can't just dump a church into a factory and call it a day.
 
rktect 1 said:
Coug Dad said:
Honestly, I can give them the 60 foot separation because under the 1996 BOCA it allowed the A-3 unlimited area with the same criteria as the F-1 which is the 3 hr rated wall. But the 5-6 foot tall 10,000 sq. ft. platform was not designed and installed under BOCA. This is currently an F-1 use. So, either they need to find a way out of unlimited area to allow the platform or lower the platform, which they will not do.
1996 BOCA is irrelevant. Current codes are what matter.
 
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