UL Design U411

2-Hour Fire Rated Two-hour non-bearing steel stud wall

UL Design U411 — Two-hour non-bearing steel stud wall. Studs are min 2-1/2 in. deep, min 25 MSG galvanized steel, spaced max 24 in. o.c., cut 3/4 in. less than assembly height, set in min 25 MSG floor and ceiling runners fastened 24 in. o.c. Two layers of 5/8 in. gypsum board are applied vertically to each side: the inner layer is screw-attached with 1 in. Type S screws 8 in. o.c. at vertical edges and 12 in. o.c. in the field, and the outer layer is laminated to the inner layer with joint compound (or alternatively screw-attached with 1-5/8 in. Type S screws 16 in. o.c.). Mineral wool or glass fiber batts in the cavity are optional.