What is the Longitudinal Seam and Transverse Joint in Rectangular Duct?
- SMACNA refers to the Longitudinal as a seam and Transverse as a joint.
- A seam is securing together two longitudinal oriented edges of duct in the direction of airflow.
- A joint is the Transverse connection that connects the end of one duct section to another.
- The Longitudinal Seam in Rectangular Duct is either a Pittsburgh Lock or a “Snap” Lock. Both types are formed on a machine that takes a sheet of metal and rollforms a profile on each of the flat edges — a Male Flange on one edge and a Female Pocket on the other edge.
- The Transverse Connection options are Slip & Drive, Ductmate, or TDC/F. Of these, only Ductmate is an entirely separate component. Both Slip & Drive and TDC/F involve rollforming a profile on the edge of the metal.