Today’s inspection. I have a interior furnace closet that is separated from the attic with fiberglass insulation in the wall but no drywall. Does it have to be separated with drywall? The insulation is Kraft paper backed and there is not any combustion venting unless they think air passing through the fiberglass is good enough, but that’s all another story. One year old town home.
Combustion air vents must be unobstructed.
I don’t have my references in front of me, but I know the UBC requires a 1 hour separation (drywall or sheet metal) at the closet ceiling. I believe the IRC does as well, but I can’t verify that right now. . .
The kraft facing on fiberglass insulation is flammable and DOES need to be protected by at least 1/2" drywall or other type of approved wall covering as a fire separation.
The Energy Codes also require that if this fiberglass insulated wall is exposed to the interior of the attic (as would be a 'knee wall") then it wust be sealed with and ‘air barrier’ on the attic side of the insulation.
See section R315 for “Flame Spread and Smoke Density” ratings under the 2003-2006 IRC Codes…
And section N1102.4.1 under the IRC 2006 and IECC 2006 section 402.4
As previously posted the insulation must be covered with 5/8" drywall (considered fire rated) and if it’s in a closet the unit needs make-up air, usually with louvered door.
Thanks everyone you confirmed everything for me.