Double Wall Spiral Duct Specifications

Dual wall double wall insulated spiral is available with solid or perforated liners.

Double wall spiral duct specifications.

These holes effectively channel system noise flanking noise and cross talk noise into the insulation layer where it is absorbed. This requirement is applicable to 20 gauge or less in thickness and 3 w g. 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. 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.

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. K value is 0 27. 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. Aluminum double wall flat oval duct and fittings are available in larger sizes and greater metal thicknesses on special order.

1 2 and 3 insulation thicknesses are available. 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. Mylar barrier is available as a barrier between perforated liner and insulation.