architect629
Member
My firm does interior fit out projects in the North East. We typically work with buildings of non-combustible construction, but we've run across a project recently that is constructed with open web wood roof trusses. I haven't had the pleasure of working with this type of construction (aside from residential) in my 15+ year career. I'm being told things by contractors bidding the projects that are "typical of this type of construction", that I'm not seeing in the code.
Here's some info about the project.
Type 5B construction, roughly 10,000 s.f.
Fully sprinklered, in both the attic and occupied space.
B occupancy with a large (>10% of floor area) storage function (S-2) which requires separation by a one hour fire barrier
Under 2012 IBC
I've been told by contractors that we need to install a layer of drywall on the underside of the existing wood roof trusses. I believe there's a requirement in the IRC to cover floor & roof framing, but I don't see anything in the IBC. The only thing I potentially see in the IBC is the fire blocking section. Would we need to create a fire block across the underside of the entire attic?
The contractors are also asking if they can stop the rated partitions at the underside of the roof trusses (which would have a layer of drywall on them). This is apparently "typical". Per the IBC a fire barrier is to be continuous from the slab to the underside of the sheathing. Even if you added drywall to the underside of the truss and created a one hour rated roof assembly, the fire barrier would need to extend to the sheathing. Am I missing anything?
Here's some info about the project.
Type 5B construction, roughly 10,000 s.f.
Fully sprinklered, in both the attic and occupied space.
B occupancy with a large (>10% of floor area) storage function (S-2) which requires separation by a one hour fire barrier
Under 2012 IBC
I've been told by contractors that we need to install a layer of drywall on the underside of the existing wood roof trusses. I believe there's a requirement in the IRC to cover floor & roof framing, but I don't see anything in the IBC. The only thing I potentially see in the IBC is the fire blocking section. Would we need to create a fire block across the underside of the entire attic?
The contractors are also asking if they can stop the rated partitions at the underside of the roof trusses (which would have a layer of drywall on them). This is apparently "typical". Per the IBC a fire barrier is to be continuous from the slab to the underside of the sheathing. Even if you added drywall to the underside of the truss and created a one hour rated roof assembly, the fire barrier would need to extend to the sheathing. Am I missing anything?