Steel building classified as Type VB

[jrosedesign]

My understanding is that if a building meets the minimum requirements for it's use group, it can be classified as a less restrictive construction type.
For example, a 10,000 square foot, 1-story, pre-engineered metal building with an automatic sprinkler system could be classified as Type VB construction under business use if it meets the height and area requirements (which it does). It's not forced to be classified as Type II construction because it's a non-combustible steel building.
The definition of Type V construction in IBC 2015 602.5 supports this by stating "any materials permitted by this code" and not saying wood structure. The verbiage in 602.1.1 also supports this (and the commentary adds to the support).
I'd love to hear if anyone has any thoughts on this.

 

[classicT]

You are correct. 602.1.1 spells it out pretty clearly.

 

[steveray]

Yep....I had a customer build a PEMB and they were more comfortable building the offices inside with wood...I cautioned them that it would limit any further additions by construction type and a lack of sprinklers and he said they were never going to add on......Fast forward 10 years.....You can guess....Just something to make people aware of as they make decisions that will impact their future...

 

[Yankee Chronicler]

Yep....I had a customer build a PEMB and they were more comfortable building the offices inside with wood...I cautioned them that it would limit any further additions by construction type and a lack of sprinklers and he said they were never going to add on......Fast forward 10 years.....You can guess....Just something to make people aware of as they make decisions that will impact their future...

We are reviewing that exact situation now. 7,800 s.f. PEMB originally permitted as type II-B, occupancy to be S-1. Now they want to turn 1,800 s.f. into offices, and frame everything out of wood. We noted that this will change the entire building to type V-B construction and limit their future expansion -- owner says that's okay.

Fine. We warned him.

 

[jrosedesign]

Thank you very much! I was surprised to get push back from the AHJ. It seemed logical but wanted to confirm I haven't been doing it wrong all these years.
In our case we still went with light gauge steel studs & joists. Our issue was that the contractor was told that any wood had to be fire retardant. I pointed out there was no need because it was classified as Type VB.

 

[rktect 1]

I would agree with that.

 

[steveray]

FRTW Not necessarily required in IIB either....But not necessarily allowed either....Depends on what it is being used for

Our issue was that the contractor was told that any wood had to be fire retardant. I pointed out there was no need because it was classified as Type VB.