Type III-B? Metal Building w/ Wood Framed Mezzanine

[Sector3]

This is an existing building. We are looking at a prefabricated steel framed building, insulated, metal siding, business use. At some point, a mezzanine was added consisting of wood structural columns and LVLs, and engineered wood I-joists framing the floor.

Does the mezzanine kick us from Type II-B into Type III-B?

Thank you for your input.

 

[cda]

Welcome

 

[Francis Vineyard]

In accordance with Table 601 III-B has 2-hr. load bearing exterior walls.

II-B should be non-combustible provided with the exceptions of section 603.

V-B would fit construction type.

 

[steveray]

Agree with FV....

 

[Sector3]

Thanks for your input. The building has no bearing walls, it's a steel frame. So all walls are non-bearing.

 

[Francis Vineyard]

Then it could III-B

See 704.10 in reference to footnote f, if the metal or steel that supports the exterior wall is framed as part of the interior wall will need to be protected.

Each methods of assembly will need to be considered on a case by case basis to determine the appropriate construction type.

 

[steveray]

The devil is in the details where the primary frame may or may not be part of the exterior wall....

 

[Sector3]

@Francis Vineyard , @steveray ,

Thanks for writing back. The steel frame is 'interior' of the exterior wall, as the exterior wall passes continuously on the outside of the structure. However, I do not believe the exterior walls are 2 hour.

So it sounds like we'll need to dig into V-B and see how that affects the building as a whole.

 

[Francis Vineyard]

"You have a building with a primary structure that is not required to be rated under Table 601
You have non-bearing exterior walls which are not required to be rated per Table 601
704.10 sends you to 601. You meet the requirements in 601 for a IIIB building classification"

Topic Thread: Metal Bldg has no bearing walls - Is it always a type III-B?

 

[ADAguy]

Back in the day didn't we call these "Butler" built buildings? Even allowed them to be installed on property lines in industrial areas.

 

[steveray]

Butler, ceco, there are a few...

 

[Sector3]

Thanks, @Francis Vineyard !