A. General Fabrication Requirements: Comply with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Ch. 3, "Round, Oval, and Flexible Duct," based on indicated static-pressure class unless otherwise indicated.
- Construct ducts of galvanized sheet steel unless otherwise indicated. 304SS Optional.
- Basis-of-Design Product: Subject to compliance with requirements, provide Nordfab Ducting, LLC; Quick Fit (QF) Duct.
B. Connection Joints: Joint types are fabricated in accordance with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," for static-pressure class, applicable sealing requirements, materials involved, duct-support intervals, and other provisions in SMACNA's "HVAC Duct Construction Standards - Metal and Flexible."
- Quick Fit Joints in Ducts 3 to 24 inches (76 to 510 mm) in diameter. Flange: Optional.
- Flanged Joints in All Ducts Greater than 24 inches (610 mm) in diameter.
C. Longitudinal Seams: Seam types are fabricated in accordance with SMACNA's "HVAC Duct Construction Standards - Metal and Flexible," Figure 3-2, "Round Duct Longitudinal Seams," for static-pressure class, applicable sealing requirements, materials involved, duct-support intervals, and other provisions in SMACNA's "HVAC Duct Construction Standards - Metal and Flexible."
- Fabricated round ducts 3 to 24 inches (76 to 510 mm) in diameter to have laser-welded or plasma-welded longitudinal seams.
- Fabricated round ducts above 24 inches (610 mm) in diameter to have plasma-welded longitudinal seams.
