Double Wall Spiral Duct Specifications

In double wall round spiral duct a metal inner liner insures that high airflow velocities cannot separate insulation by pulling away from the duct s outer wall and creating erosion or airflow problems.

Double wall spiral duct specifications.

Standard lengths of longitudinal seam k27 duct are 5 and 6 feet. These holes effectively channel system noise flanking noise and cross talk noise into the insulation layer where it is absorbed. Double wall flat oval duct and fittings are also available in carbon steel paintable galvanized steel and a luminized steel. All double wall fittings are fabricated with stiffening beads on duct sizes 19 wide and larger which have more than 10 square feet of unbraced panel.

When noise reduction is required the inner wall of dual wall spiral pipe is perforated with thousands of 3 32 holes on 3 16 centers. This requirement is applicable to 20 gauge or less in thickness and 3 w g. Aluminum double wall flat oval duct and fittings are available in larger sizes and greater metal thicknesses on special order. Mylar barrier is available as a barrier between perforated liner and insulation.

Double wall fittings are manufactured on our state of the art fabrication equipment. Smc constructs each piece with an inner shell perforated or solid surrounded by a layer of insulation and covered by a solid outer shell. Smc double wall round spiral duct is a dependable erosion resistant alternative to lined round spiral duct providing improved protection for insulation exposed to the airstream. K value is 0 27.