Getting ready to work on what I'm pretty sure is a type 2B building (haven't done the code study yet, but starting Monday). It's steel frame, steel bar joist / concrete pan floors, steel stud walls, gypsum board. I'm thinking the roof structure is wood trusses. Am I right that this would be a type 2B building - that wood is allowed for roof framing in type 2B? I've done loads of 2B buildings, but we've always done metal / concrete roofs. If you've done wood for 2B roof - is there any requirement for fire treatment or membrane protection on the wood? In other words, at the top level, can we do an unrated ceiling, or does it need some sort of protection? What about the amount of space that can be in the attic - any requirement for blocking it off every XX square feet / cubic feet, etc? Obviously, I'll do my own code review in my jurisdiction, but hoping someone with practical knowledge can point out pitfalls to me. FWIW - our local code is IBC 2009 with local edits.
curtkram
Sep 10, 16 11:19 am
wood is typically considered "combustible" construction. if you have wood joists, you're probably not 2b. probably should consider calling it type 3. is this multifamily?
poop876
Sep 11, 16 8:45 am
Funny you mention this. Just did a interior renovation and the entire building was metal except the roof and I had no idea why they did it and they called it 2b. Based on areas and heights, I reclassified the entire building to be 5b. They can still use 2b construction if they want but they don't have to.
I guess without more information on the building it's hard to tell if it's 2b in your case.
b3tadine[sutures]
Sep 11, 16 9:28 am
Is the wood fire treated? 603 seems to be one place to look.
Janosh
Sep 11, 16 10:14 am
Look for the exception related to distance from the last occupied floor to the underside of roof assembly.
gruen
Sep 11, 16 1:34 pm
I'll be getting the original drawings tomorrow. Pretty sure there is an exception for wood roof type 2b. Way too big to be type 5.
Probably 601.1.1.3 fire retardant treated wood roof framing. I'll report back after reviewing the original drawings.
gruen
Sep 13, 16 4:43 pm
turns out that the building is multiple generations of construction. The oldest is type 2b, everything metal (including the roof). The newest is type 5b, and is properly separated with a fire wall. However, there was an intermediate stage that joins the oldest and newest, and it's wood framed and not separated. It'll take a larger study to see if this converts the oldest part to type 5b and if any addition is allowed. They have sprinklers and good frontage so that helps.
I guess my original question is moot - the building isn't type 2b with wood roof...
JeromeS
Sep 13, 16 6:02 pm
If memory serves and i understand the description, its all 5b. Your client is Effed, or should find a less qualified building designer, or move the building to Oregon.
Getting ready to work on what I'm pretty sure is a type 2B building (haven't done the code study yet, but starting Monday). It's steel frame, steel bar joist / concrete pan floors, steel stud walls, gypsum board. I'm thinking the roof structure is wood trusses. Am I right that this would be a type 2B building - that wood is allowed for roof framing in type 2B? I've done loads of 2B buildings, but we've always done metal / concrete roofs. If you've done wood for 2B roof - is there any requirement for fire treatment or membrane protection on the wood? In other words, at the top level, can we do an unrated ceiling, or does it need some sort of protection? What about the amount of space that can be in the attic - any requirement for blocking it off every XX square feet / cubic feet, etc? Obviously, I'll do my own code review in my jurisdiction, but hoping someone with practical knowledge can point out pitfalls to me. FWIW - our local code is IBC 2009 with local edits.
wood is typically considered "combustible" construction. if you have wood joists, you're probably not 2b. probably should consider calling it type 3. is this multifamily?
Funny you mention this. Just did a interior renovation and the entire building was metal except the roof and I had no idea why they did it and they called it 2b. Based on areas and heights, I reclassified the entire building to be 5b. They can still use 2b construction if they want but they don't have to. I guess without more information on the building it's hard to tell if it's 2b in your case.
Is the wood fire treated? 603 seems to be one place to look.
Look for the exception related to distance from the last occupied floor to the underside of roof assembly.
I'll be getting the original drawings tomorrow. Pretty sure there is an exception for wood roof type 2b. Way too big to be type 5.
http://codes.iccsafe.org/app/book/content/PDF/2009%20International%20Codes/IBC/Chapter%206-Types%20of%20Construction.pdf
Probably 601.1.1.3 fire retardant treated wood roof framing. I'll report back after reviewing the original drawings.
turns out that the building is multiple generations of construction. The oldest is type 2b, everything metal (including the roof). The newest is type 5b, and is properly separated with a fire wall. However, there was an intermediate stage that joins the oldest and newest, and it's wood framed and not separated. It'll take a larger study to see if this converts the oldest part to type 5b and if any addition is allowed. They have sprinklers and good frontage so that helps.
I guess my original question is moot - the building isn't type 2b with wood roof...
If memory serves and i understand the description, its all 5b. Your client is Effed, or should find a less qualified building designer, or move the building to Oregon.
Lol.