WIJ-1.3 One-Hour Fire-Resistive Ceiling Assembly
Floora/Ceiling - 100% Design Load - 1 Hour Rating - ASTM E 119 / NFPA 251

1. Floor Topping (optional, not shown): Gypsum concrete, lightweight or normal concrete topping.
2. Floor Sheathing: Minimum 23/32 inch thick tongue-and-groove wood sheathing (Exposure 1). Installed per code requirements.
3. Insulation: Minimum 2 inch thick mineral wool insulation batts – 3.5 pcf (nominal), supported by setting strip edges, friction-fitted between the sides of the I-joist flanges.
4. Structural Members: Wood I-joists spaced a maximum of 24 inches on center.
      Minimum I-joist flange depth: 1-5/16 inches Minimum I-joist flange area: 2.25 inches2
      Minimum I-joist web thickness: 3/8 inch Minimum I-joist depth: 9-1/4 inches
     
Types of Adhesives Used in Tested I-Joists
LVL Flange Adhesive Flange-to-Web Joint Web-to-Web Endjoint
Phenol-Resorcinol-Formaldehyde Emulsion Polymer Isocyanate Polyurethane Emulsion Polymer

5. Setting Strips: Nominal 1x4 wood setting strips attached with 1-1/2 inch long drywall screws at 24 inches on center along the bottom flange of I-joist creating a ledge to support insulation.
6. Resilient Channels: Minimum 0.019 inch thick galvanized steel resilient channels, attached perpendicular to I-joists using 1-7/8 inch long drywall screws. Resilient channels spaced 16 inches on center and doubled at each wallboard end joint extending to the next joist.
7. Gypsum Wallboard: Minimum 5/8 inch thick Type C gypsum wallboard installed with long dimension perpendicular to resilient channels and fastened to each channel with minimum 1-1/8 inch long Type S drywall screws. Fasteners spaced 7 inches on center and 3/4 inches from panel edges and ends. End joints of wallboard staggered.
8. Finish System (not shown): Face layer joints covered with tape and coated with joint compound. Screw heads covered with joint compound.

      Fire Test conducted at National Gypsum Testing Services, Inc. September 28, 2001
      Third Party Witness: Underwriter’s Laboratories, Inc. Report No: NC3369

STC and IIC Sound Ratings for Listed Assembly
Without Gypsum Concrete With Gypsum Concrete
Cushioned Vinyl Carpet & Pad Cushioned Vinyl Carpet & Pad
STC IIC STC IIC STC IIC STC IIC
51 b 46 b 52 66 60 b 48 b 60 b 60 b
a This assembly may also be used in a fire-rated roof/ceiling application, but only when constructed exactly as described.
b STC and IIC values estimated by David L. Adams Associates, Inc


Copyright © 2002, 2007
AMERICAN WOOD COUNCIL                       AMERICAN FOREST & PAPER ASSOCIATION, INC                                             February 2007