Four layers of 5/8” (15.9 mm) ToughRock® Fireguard C® gypsum board or 5/8” (15.9 mm) DensArmor Plus® Fireguard C® covering W10 x 49 (metric W250 x 73) steel column. Inner Layer: Attached to steel studs with 1” (25 mm) long self-drilling, self-tapping screws spaced vertically 24” (610 mm) o.c. Second Layer: Attached to steel studs with 1-5/8” (41 mm) long self-drilling, self-tapping screws spaced vertically 24” (610 mm) o.c. Third Layer: Attached to sheet-metal angles with 1” (25 mm) long, self-drilling, self-tapping screws spaced vertically 12” (305 mm) o.c. Outer Layer: Gypsum board attached to the sheet metal angles with 1-5/8” (41 mm) long selfdrilling, self-tapping screws spaced vertically 12” (305 mm) o.c.
