Construction Standards for Spiral Round Duct
Round spiral lock-seam duct is the most efficient way to transport air in HVAC systems. The round profile has greater flow efficiencies than rectangular ducts. Round ducts are inherently stronger than rectangular profiles, they can be lighter metal gauges and can be installed in longer spans. The 4-ply spiral lock-seams of “spiral duct” create a product that is stronger than traditional welded-seam round ducts of the same gauge. Spiral lock-seams have practically no leakage, and are the only mechanical seams exempted from sealing under energy standards such as ASHRAE Standard 90.1 – 2013.
At Spiral Pipe of Texas, we make products that meet or exceed the SMACNA HVAC Duct Construction Standards – Metal and Flexible (2005). We make diameters ranging from 3” to 92” and metal thicknesses from 26 gauge to 16 gauge. The following is our construction standard for positive pressures to +10” WG.
Standard fittings to be spot welded and sealed. Continuously welded seam fittings are available if specified. All PCD and SPOT Agion fittings are riveted and sealed.
G90 Galvanized Steel
A40 & A60 Galvannealed Steel
304 and 316 Stainless Steel
SPOT AgION (Antimicrobial Coating)
PCD (Polyvinyl Coated Galvanized)
Standard Slip-Fit / Couplings
½” Weld Flange
Special materials and connectors may be available. Please contact your nearest representative for details.