IBC Design 721.1(2) 15-1.11

1-Hour Fire Rated Exterior or interior walls — Steel studs 0.060" thick, 4" deep or 6" at 16" or 24" centers…

IBC Table 721.1(2), Item 15-1.11 (Exterior or interior walls): Steel studs 0.060" thick, 4" deep or 6" at 16" or 24" centers, respectively, with 1/2" glass fiber-reinforced concrete (GFRC) on the exterior surface. GFRC is attached with flex anchors at 24" on center, with 5" leg welded to studs with two 1/2"-long flare-bevel welds, and 4" foot attached to the GFRC skin with 5/8"-thick GFRC bonding pads that extend 2-1/2" beyond the flex anchor foot on both sides. Interior surface to have one layer of 5/8" Type X gypsum wallboard (e), attached with 1-1/4"-long Type S buglehead screws spaced 12" on center. Cavity is to be filled with 5" of 4 pcf (nominal) mineral fiber batts. GFRC has 1-1/2" returns packed with mineral fiber and caulked on the exterior. Minimum finished thickness (face-to-face) — 1-hr: 6-1/8". Prescriptive assembly from the adopted building code — thicknesses are code minimums, see table footnotes for conditions.