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INSPECTION & INSTALLATION
4.7.2 Alternate Installation Instructions for Air Ducts and Air Connectors - Nonmetallic with Plain Ends
Connections and Splices - Using Mastic and Fasteners
Step 1 After desired length is determined, cut completely around and through duct with knife or scissors. Cut wire with wire cutters. Pull back jacket and insulation from core.
Step 2 Apply mastic approximately 2" [50 mm] wide uniformly around the collar of the metal fitting or over the ends of a 4" [100 mm] min. length metal sleeve. Reference data on mastic container for application rate, application thickness, cure times and handling information.
Step 3 Slide at least 2" [50 mm] of core over the fitting or sleeve ends and past the bead.
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Step 4 Secure core to collar with a clamp applied past the bead. Secure cores to sleeve ends with 2 clamps applied past the beads.
Step 5 Pull jacket and insulation back over core ends. Tape jacket(s) with at least 2 wraps of duct tape. A clamp may be used in place of or in combination with the duct tape.
NOTES: 1. For uninsulated air ducts and air connectors, disregard references to insulation and jacket. 2. Use beaded sheet metal fittings and sleeves when using nonmetallic clamps. 3. Use mastics listed and labeled in accordance with Standard UL 181B and marked “181 B - M ” on container. 4. Use tapes listed and labeled in accordance with Standard UL 181B and marked “181 B - FX ”. 5. Nonmetallic clamps shall be listed and labeled in accordance with standard UL 181B and marked “181 B - C ”. Use of nonmetallic clamps shall be limited to 6 in. w.g. [1500 Pa] positive pressure.
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