W-L-7122

F Ratings — 1 and 2 Hr (See Item 1)

T Ratings — 0 and 3/4 Hr (See Item 1)

1. Wall Assembly — The 1 or 2 hr fire-rated gypsum board/steel stud wall assembly shall be constructed of the materials and in the manner specified in the individual U400 and V400 Series Wall and Partition Designs in the UL Fire Resistance Directory and shall incorporate the following construction features:
A. Studs — Wall framing shall consist of min 3-5/8 in. wide steel channel studs spaced max 24 in. OC. Additional 3-5/8 in. wide steel studs shall be used to completely framed the opening.
B. Gypsum Board* — One or two layers of nom 1/2 or 5/8 in. (13 or 16 mm) thick gypsum board as specified in the individual Wall and Partition Design. The gypsum board type, thickness, number of layers, fastener type and sheet orientation shall be as specified in the individual U400 Series Design in the UL Fire Resistance Directory. Max area of opening is 900 sq in. with max dimensions of 30 in.
The hourly F Rating of the firestop system is equal to the hourly fire rating of the wall assembly in which it is installed. The T Ratings are 0 and 3/4 hr when installed in 1 and 2 hr rated walls, respectively.

2. Steel Duct — One nom 26 by 26 in. (or smaller) No. 24 gauge (or heavier) steel air duct installed within the firestop system. Duct to be rigidly supported on both sides of wall assembly.

3. Duct Insulation* — Nom 1-1/2 in (38 mm) thick glass fiber blanket insulation jacketed on the outside with an aluminum foil reinforced glass-fiber-scrim-kraft facing. Longitudinal and tranverse joints sealed with a pressure sensitive foil tape. The annular space within the firestop system shall be min 1/4 in. (6 mm) to max 1-1/4 in. (32 mm).
See Batts and Blankets (BKNV) category in the Building Materials Directory for names of manufacturers. Any batts and blankets material meeting the above specifications and bearing the UL Classification Marking with a Flame Spread Index of 25 or less and a Smoke Developed Index of 50 or less may be used.

4. Firestop System — The firestop system shall consist of the following:
A. Fill, Void or Cavity Materials* — Nom 1/16 in. thick intumescent material supplied in 1-1/2 in. (38 mm) wide strips. Min 1 layer of joint strip wrapped tightly around the duct insulation, protruding 1/2 in (13 mm) beyond each surface of the wall. Joint strip held in position with tape.
RECTORSEAL — Metacaulk Joint Strip

B. Packing Material - (Optional) — Foam backer rod firmly packed into the opening as a permanent form. Packing material to recessed from both sides of wall to accommodate the required thickness of fill material.
C. Fill, Void or Cavity Material* - Caulk — Min 5/8 in. (16 mm) thickness of caulk applied within annulus, flush with both surfaces of the wall assembly.
RECTORSEAL — Metacaulk 1000, MC 150+