722.6.2 Walls, floors and roofs.
BC § 722.6.2
These procedures apply to both load-bearing and nonload-bearing assemblies. Table 722.6.2(1)Time Assigned to Wallboard Membranes a, b, c, d Description of FinishTime e (minutes)Description of FinishTime e (minutes)3/8-inch wood structural panel bonded with exterior glue515/32-inch wood structural panel bonded with exterior glue1019/32-inch wood structural panel bonded with exterior glue153/8-inch gypsum wallboard101/2-inch gypsum wallboard155/8-inch gypsum wallboard301/2-inch Type X gypsum wallboard255/8-inch Type X gypsum wallboard40Double 3/8-inch gypsum wallboard251/2- + 3/8-inch gypsum wallboard35Double 1/2-inch gypsum wallboard40 For SI: 1 inch = 25.4 mm. a. These values apply only where membranes are installed on framing members that are spaced 16 inches o.c or less. b. Gypsum wallboard installed over framing or furring shall be installed so that all edges are supported, except 5/8-inch Type X gypsum wallboard shall be permitted to be installed horizontally with the horizontal joints staggered 24 inches each side and unsupported but finished. c. On wood frame floor/ceiling or roof/ceiling assemblies, gypsum board shall be installed with the long dimension perpendicular to framing members and shall have all joints finished. d. The membrane on the unexposed side shall not be included in determining the fire resistance of the assembly. Where dissimilar membranes are used on a wall assembly, the calculation shall be made from the least fire-resistant (weaker) side. e. The time assigned is not a finished rating. Table 722.6.2(2)Time Assigned for Contribution of Wood Frame a, b, c DescriptionTime Assigned to Frame (minutes)Wood studs 16 inches o.c.20Wood floor and roof joists 16 inches o.c10 For SI: 1 inch = 25.4 mm. a. This table does not apply to studs or joists spaced more than 16 inches o.c. b. All studs shall be nominal 2 × 4 and all joists shall have a nominal thickness of not less than 2 inches. c. Allowable spans for joists shall be determined in accordance with Sections 2308.4.2.1, 2308.7.1 and 2308.7.2. Table 722.6.2(3)Membrane a on Exterior Face of Wood Stud Walls SheathingPaperExterior Finish5/8-inch T & G lumber5/16-inch exterior glue plywood1/2-inch gypsum wallboard5/8-inch gypsum wallboard1/2-inch fiberboardSheathing paperLumber sidingWood shingles and shakes1/4-inch fiber-cement lap, panel or shingle siding1/4-inch wood structural panels-exterior type1/4-inch hardboardMetal sidingStucco on metal lathMasonry veneerVinyl sidingNone–3/8-inch exterior-grade wood structural panels For SI: 1 inch = 25.4 mm. a. Any combination of sheathing, paper, and exterior finish is permitted. Table 722.6.2(4)Flooring or Roofing over Wood Framing a AssemblyStructural MembersSubfloor or Roof DeckFinished Flooring or RoofingFloorWood15/32-inch wood structural panels or 11/16 inch T & G softwoodHardwood or softwood flooring on building paper resilient flooring, parquet floor felted-synthetic fiber floor coverings, carpeting, or ceramic tile on 1/4-inch-thick fiber-cement underlayment or 3/8-inch-thick panel-type underlayCeramic tile on 1 1/4-inch mortar bedRoofWood15/32-inch wood structural panels or 11/16 inch T & G softwoodFinished roofing material with or without insulation For SI: 1 inch = 25.4 mm. a. This table applies only to wood joist construction. It is not applicable to wood truss construction. Table 722.6.2(5)Time Assigned for Additional Protection Description of Additional ProtectionFire Resistance (minutes)Add to the fire-resistance rating of wood stud walls if the spaces between the studs are completely filled with glass fiber mineral wool batts weighing not less than 2 pounds per cubic foot (0.6 pound per square foot of wall surface) or rockwool or slag material wool batts weighing not less than 3.3 pounds per cubic foot (1 pound per square foot of wall surface), or cellulose insulation having a nominal density not less than 2.6 pounds per cubic foot.15 For SI: 1 pound/cubic foot = 16.0185 kg/m 3 .
