Spiral duct is a round ductwork constructed by spirally winding a continuous ribbon of metal with a helical seam, creating a rigid and durable ducting system. Spiral duct offers superior strength compared to rectangular ductwork and maintains structural integrity with less reinforcement required. The helical seam provides uniform pressure distribution and can withstand static pressures up to 10 inches of water column.
Construction and Advantages
Spiral duct is manufactured from galvanized steel, stainless steel, or aluminum in diameters from 3 to 60 inches. The continuous spiral seam eliminates weak points found in traditional snap-lock construction. Installation costs are typically 15 to 25 percent lower than rectangular duct due to faster assembly and fewer fittings required.
Performance Characteristics
Spiral ductwork provides superior velocity characteristics and lower friction loss compared to rectangular ducts. The round profile reduces installation space and weight by approximately 30 percent. Standard spiral duct includes both galvanized and insulated options for applications requiring thermal control or condensation prevention.