TDC, known as transverse duct connection, is a flange c […]
TDC, known as transverse duct connection, is a flange constructed from the main duct sheet as per duct manufacture catalogs which means it is attached to it it has the same duct gauge.
Basically they are conner pieces that go into a groove that is formed into the ductwork.
While TDF, which named transverse duct flange, is a separate manufactured flange (slip on flange) that you can fix it on the main duct.
Transverse Duct Flange is on based to the construction standards follow SMACNA. It may has the same duct gauge or more, you can buy it separately as an accessories.
Basicaly "f" corners. They are nicer to use, and snap into place. Unlike TDC, the normally do no need to be crimped like "c" corners.
In short, TDC is just a connection. TDF is the slips or other kind of fixtures.
Both type of corners have bolt holes, and two pieces of duct are bolted, and clips installed (usally 6" long, about 6" apart).
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