WIJ-1.7 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 with minimum 8d common nails.
3. Insulation: Fiberglass insulation placed between I-joists supported by the resilient channels.
4. Structural Members: Wood I-joists spaced a maximum of 24 inches on center.
      Minimum I-joist flange depth: 1-1/2 inches Minimum I-joist flange area: 2.25 inches2
      Minimum I-joist web thickness: 3/8 inch Minimum I-joist depth: 9-1/2 inches
     
See ASTM D 5055-07 for qualification requirements.

5. Resilient Channels: Minimum 0.019 inch thick galvanized steel resilient channel attached perpendicular to the bottom flange of the I-joists with one 1-1/4 inch drywall screw. Channels spaced a maximum of 16 inches on center [24 inches on center when I-joists are spaced a maximum of 16 inches on center].
6. Gypsum Wallboard: Two layers of minimum 1/2 inch Type X gypsum wallboard attached with the long dimension perpendicular to the resilient channels as follows:
      6a. Wallboard Base Layer: Base layer of wallboard attached to resilient channels using 1-1/4 inch Type S drywall screws at 12 inches on center.
      6b. Wallboard Face Layer: Face layer of wallboard attached to resilient channels through base layer using 1-5/8 inch Type S drywall screws spaced 12 inches on center. Edge joints of wallboard face layer offset 24 inches from those of base layer. Additionally, wallboard face layer attached to base layer with 1-1/2 inch Type G drywall screws spaced 8 inches on center, placed 1-1/2 inches from face layer end joints.
7. 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 Research Council of Canada Report No: A-4219.13.2      March 23, 1998     

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
59 50 55 b 68 b 65 51 63 b 65 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, 2009
AMERICAN WOOD COUNCIL                       AMERICAN FOREST & PAPER ASSOCIATION, INC                                             January 2009