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Rectangular And Spiral

DoubleWall Products

Please note that the following list is but a sample of the Double Wall that Shade Tree Mfg. LLC produces. Configurations are subject to change. Call or e-mail us and we will be happy to supply you with our most recent product catalog and answer any questions you may have.

Rectangular Double Wall

All rectangular duct and fitting sections are made standard with flanged connection for attachment to other ducts or fittings (Slips/Drives and other connections available on request). The exterior shell of the duct segments are fabricated from hot-dipped G90 galvanized steel that meets or exceeds SMACNA standards, and installed with a bolt-together flanged connection system (e.g. Ward, WDCI, Ductmate, TDC/TDF type). Outer shell construction follows Shade Tree Mfg. gauge specifications for standard single wall rectangular construction (SMACNA Spec).

The inner layer is fabricated from minimum 22 Ga G90 galvanized perforated steel with 1/8" holes on a 3/16" stagger and either wraps out at the joint ends to be tack-welded into place against the flange connector or flanges short of the duct/fitting end to accommodate slips/drives.

Sandwiched between the inner and outer layer is an insulation layer fabricated from fiberglass liner of thickness and density appropriate for the desired wall thickness (e.g. 1-1/2" regular density or 1" High Density for 1" Double Wall)

Please see our section on rectangular galvanized duct for further information on naming conventions for fittings to facilitate information requests and orders. Note that because of the layout inconsistencies between the outer wall and inner layer, certain transitional combinations and curved fitting specifications may not be able to be produced in a single fitting. Unless otherwise specified, given dimensions will be taken as outside construction dimensions, so make sure to fully note dimensions and wall thickness.


Spiral Double Wall

Round and Oval

All spiral duct and fitting sections (Round and Oval) are made standard with male slip fit connection for attachment to other ducts or fittings (Flanged connections available on request). The exterior shell of the duct segments are fabricated from hot-dipped G90 galvanized steel that meets or exceeds SMACNA standards, and installed with a flanged connection system (Ward, WDCI, Ductmate type). Outer shell construction follows Shade Tree Mfg. gauge specifications for standard single wall spiral construction, and charts indicating those specifications can be found in those sections of our product literature.

The inner layer is fabricated from minimum 22 Ga G90 galvanized perforated steel with 1/8" holes on a 3/16" stagger.

Sandwiched between the inner and outer layer is an insulation layer fabricated from fiberglass liner of thickness and density appropriate for the desired wall thickness (e.g. 1-1/2" regular density or 1" High Density for 1" Double Wall)

Pipe connections to other pipe segments are accomplished with male slip connectors (similar to single wall male connectors). Two slip connectors are required for each joint connection: a long connector sized to connect the inner liners and a short connector to connect the outer shells. Fittings are made standard male slip fit to insert into standard pipe segments. Fitting inner liner is made 2" longer to facilitate connections with pipe segments.
Optional flange connections are accomplished by attaching standard flanged connector to the outer shell at the pipe/fitting joint ends and welding an inner ring into place against the flange connector.
Please see our section on spiral galvanized round and oval duct for further information on naming conventions for fittings to facilitate information requests and orders. Note that because of the layout inconsistencies between the outer wall and inner layer, certain transitional combinations and curved fitting specifications may not be able to be produced in a single fitting. Unless otherwise specified, given dimensions will be taken as outside construction dimensions, so make sure to fully note dimensions and wall thickness.