UL Design V450

1-Hour Fire Rated Non-bearing steel stud wall rated 1, 2 or 2-1/2 hours

UL Design V450 — Non-bearing steel stud wall rated 1, 2 or 2-1/2 hours. Channel-shaped studs of min 0.0150 in. bare metal thickness galvanized steel spaced max 24 in. o.c. (min 3-5/8 in. wide for the 1-hour system; min 1-5/8 in. for 2-hour; min 2-1/2 in. for 2-1/2-hour; studs cut 3/4 in. short of assembly height for the 2- and 2.5-hour systems). The 1-hour rating uses one layer of 5/8 in. gypsum board each side; the 2- and 2-1/2-hour ratings use two layers of 5/8 in. each side, applied vertically or horizontally. Boards are fastened with Type S or S-12 bugle-head screws, typically 8 in. o.c. at the perimeter and 12 in. o.c. in the field. Glass fiber or mineral wool batts are optional, friction-fit in the cavity.