IBC Design 721.1(2) 15-1.9

2-Hour Fire Rated Exterior or interior walls — 4" No. 18 gage, nonload-bearing metal studs, 16" on center, with 1"…

IBC Table 721.1(2), Item 15-1.9 (Exterior or interior walls): 4" No. 18 gage, nonload-bearing metal studs, 16" on center, with 1" Portland cement lime plaster (measured from the back side of the 3/4-pound expanded metal lath) on the exterior surface. Interior surface to be covered with 1" of gypsum plaster on 3/4-pound expanded metal lath proportioned by weight—1:2 for scratch coat, 1:3 for brown, gypsum to sand. Lath on one side of the partition fastened to 1/4" diameter pencil rods supported by No. 20 gage metal clips, located 16" on center vertically, on each stud. 3" thick mineral fiber insulating batts friction fitted between the studs. Minimum finished thickness (face-to-face) — 2-hr: 6-1/2 (d)". Prescriptive assembly from the adopted building code — thicknesses are code minimums, see table footnotes for conditions.