IBC Design 721.1(2) 14-1.2

1-Hour Fire Rated Wood studs—interior partition with gypsum wallboard each side — 2" x 4" wood studs 16" on center with two layers 1/2" regular gypsum…

IBC Table 721.1(2), Item 14-1.2 (l, m) (Wood studs—interior partition with gypsum wallboard each side): 2" x 4" wood studs 16" on center with two layers 1/2" regular gypsum wallboard (e) applied vertically or horizontally each side (k), joints staggered. Nail base layer with 5d cooler (n) or wallboard (n) nails at 8" on center face layer with 8d cooler (n) or wallboard (n) nails at 8" on center. Minimum finished thickness (face-to-face) — 1-hr: 5-1/2". Prescriptive assembly from the adopted building code — thicknesses are code minimums, see table footnotes for conditions.