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Help!! Two-Story A2

benny

benny

Bronze Member
Joined
Mar 23, 2010
Messages
78
Location
Idaho
I'm in a little over my head and the politics are starting to get stirred up. We use 2009 IBC.Proposed A2, came in as a Type VB, but has a mezzanine over 1/3 of the floor area; so two story. The RDP is now calling out a 2 hr wall against the existing building and calling it a IIIB. However the wall has already been framed as a one hour wall and they used standard wood studs (not fire-treated lumber). IBC 602.3 seems to say that Type IIIB is noncombustible with the exception of fire treated wood for studs. I think a VA would be doable. Basically I have a structural engineer playing architect (which our state code allows).Can they use a two-hour wall (standard studs) against the existing building along with one-hour walls on the others and call it a IIIB? I don't see it. I'm thinking either go VA or take the mezzanine down to 1/3 the lower floor area and use a one-hour wall against the existing building and call it a VB. I really appreciate your help!

View attachment 1756

AR-M455N_20130130_145414.pdf

AR-M455N_20130130_145414.pdf
 
have they submitted a UL orother tested assembly for these rated walls???

is the building sprinkled??
 
Can they use a two-hour wall (standard studs) against the existing building along with one-hour walls on the others and call it a IIIB?
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No

I'm thinking either go VA or take the mezzanine down to 1/3 the lower floor area
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That is the simple solution

and use a one-hour wall against the existing building and call it a VB
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Why the one hour wall if you already have a 2 hour IIIB existing exterior wall?
 
Nonsprinklered.

The two hour existing wall is on the neighboring property. can this building use that that wall for credit in fire separation?
 
You have the existing building classified as IIIB. The new addition has to meet the same construction type as the original building. You cannot mix construction types without firewalls seperating them into different buildings.

If the existing building will meet a type VB or VA then classify the building with the least restrictive construction.
 
Just to clarify. The neighboring building is IIIB and is on a separate property. This A2 is on a zero lot line and butting up against the neighbor's building. If I classify the neighboring building VB, don't I still need a one-hour wall based on fire separation distance? Table 602
 
Sorry I assumed this was an addition

One hour wall required when less than 10 ft from the property line also on walls that are perpendicular to the existing build may need to be rated within 10 feet of the property line

could require a parapet also
 
thank you...

This can't be a IIIB without the use of fire-treated studs or masonry exterior walls, right?
 
They are trying to call it a IIIB with a one hour wall made up of standard non-treated studs surrounded by 5/8 Type X gypsum.
 
benny said:
800 on the main floor with a 500 sqft open second floor.
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If you have A-2 occupancy at 2nd floor, anyway you need to sprinkler the building (2012 IBC Sec.903.2.1.2, condition #3).

Then, once you sprinkler the building, type VB will be OK.

OR, if you don’t want sprinkler the building, then by just increasing the main level area to 1,500 sq. ft. you can solve the problem. The resulting building will be a 1-story with 500 sq. ft. mezzanine that can be of Type VB construction.
 
benny said:
thank you...This can't be a IIIB without the use of fire-treated studs or masonry exterior walls, right?
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For Type IIIB, the exterior walls must be non-combustible. If they want to use wood in the exterior walls then they must use fire-retardant-treated wood (FRTW). As long as the walls are non-combustible, they are not limited to masonry. Concrete or other approved non-combustible materials are also permitted.
 
well now they are hoping to use IBC 303.1, exception 1 and 1004.1.1 exception and call it a "B".
 
It is the BO's call on the exception for 1004.1.1. I personally would not do it.

Remember the assembly loads are based on net sq ft of the assembly space. you can exclude the bathrooms, kitchen and storage area, the sq footage for the stairs if there is no seating under them. See if that helps

Or I have permitted the tables bolted to the floor in lieu of booth seating or fixed seating to keep the number below fifty. You can only put so many chairs around a table
 
using 15 occupants/sf comes to 72. I have a meeting with the Fire Chief and City Administrator later today to discuss their request. I've asked for a seating and egress plan showing exactly what they are requesting. I like the idea of the bolted tables.
 
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