Fabric Duct Systems, Inc.

Installation Instructions for Standard Half-Round Q-Sox by Fabric Duct Systems, Inc.

To download a PDF version of Half-Round installation instructions CLICK HERE.


 Tools Required:

  • Pencil
  • Tape measure
  • Chalk Line
  • Stud Finder (for sheet rock ceilings with joists above)
  • Power cut-off saw
  • Round file – fine cut to trim burrs on the aluminum extrusion rails
  • Power Drill, Pilot Hole Bit, Screw Driver Bits


Materials Required:

  • Q-Sox custom designed 44” diameter half-round cloth duct Sections with Glider Trak mounting.
  • Aluminum Extrusion Mounting Rail 10-foot sections


Supplied by installer:

  • Round Head Machine Screws #8-32” or larger. For
  • #8-32 anchors for gypsum panels or concrete ceilings; use appropriate sheet metal screws for mounting to suspended acoustical tile Tee bars.

NOTE: Each Duct Run is packaged with its respective, consecutive, zippered  section (s).

Construction Sequence

Installation is completed in three phases:

I.    Locating two parallel aluminum Mounting Rails on the ceiling outward from the air supply duct; marking and drilling the Rails and inserting the ceiling anchor fasteners. Fastening the Mounting Rails firmly to the ceiling.

II.    Sliding and positioning the duct run sections into the Mounting Rails

III.    Attach the Collar around the periphery of the sheet metal air inlet duct. Attach Anchor Belt and secure clamp over fabric Collar.

Phase I.

1.    Use full-length Mounting Rail sections, cutting only the last rail section to fit the required duct length.  


3.    Save all cut off Mounting Rail sections for use on other appropriate places throughout the installation. Aluminum Mounting Rail required for the job is supplied in 10-foot sections.

4.    With a tape measure, mark equal distances left and right of the centerline of the inlet duct. Mark TWO parallel chalk lines into the room for the length of the duct. Make sure these two parallel chalk lines are perpendicular to the sheet metal inlet/wall! These two chalk lines will mark the line of ceiling anchor holes to be drilled AFTER the Mounting Rails have been drilled in step 6. See attached drawing.

5.    FOR GYPSUM OR CONCRETE CEILINGS - When the Mounting Rail sections are cut to length for the entire duct run, start at THE AIR INLET END of the Mounting Rails and drill 3/16” holes in the flanges every 24 inches of both left and right Mounting Rails.  These mounting holes are located 5/16” from the outside edge of the flange. NOTE THE FLANGES POINT AWAY FROM THE DUCT CENTERLINE!

FOR ACOUSTICAL TILE CEILINGS WITH TEE BAR SUSPENSION  - Clamp the Mounting Rail sections to the Tee Bar grid and mark the Rail flanges where the Rail and Tee bars intersect. Unclamp Rails and drill appropriate size holes through flange at the Tee bar mark for a #8 sheet metal screw.

6.    Now with the drilled Mounting Rails, center the Rail holes over the chalk line and mark the ceiling where the ceiling anchors are to be located. Do this for both Rails and chalk lines.

7.    Attach both parallel Mounting Rails firmly in place to the ceiling.

Half Round Install Guide

Phase II.

1.    Next, open the FIRST Duct Section to full length. Start at the end of the installed double rails and work toward the inlet  WITH THE FIRST DUCT SECTION. Slide the Gliders on each side of the duct into the Rails and pull the duct toward the sheet metal inlet.

2. After the first duct section is installed in the Rails, prepare the next mating fabric duct section. Zipper each duct section together BEFORE attaching the Gliders to the Rails. This will facilitate zippering the sections together rather than attempting to zipper after attaching the sections to the Rails.

3.    Now begin attaching the other duct sections in sequence into their respective duct runs.  

Phase III.

1.    After all duct sections have been zippered together, slide the Anchor Belt over and around the SM inlet duct and clamp tight.

2.    Turn on the air flow fan.

3.    Stretch the duct at the End Cap and install sheet metal screws into the rail to secure the two End Cap Gliders. See the Final Adjustment attached photograph.

Final Adjustment Half Round

1. Stretch Glider at end of each duct to insure the duct is extended to its full length.

2. Drill 0.172” diameter pilot hole in bottom channel.   Align with center of white Glider.

3. Install #10 x ½” Self-tapping Sheet Metal Screw to secure the Glider in position.