TDF vs TDC Flange Systems: A Complete Comparison
Understand the differences between TDF (Transverse Duct Flange) and TDC (Transverse Duct Connector) systems, their pros, cons, and which is right for your duct fabrication.
TDF and TDC are the two dominant flange connection systems in modern rectangular duct fabrication. Understanding their differences helps you choose the right equipment.
TDF (Transverse Duct Flange): The TDF system forms a flange directly on the duct end using a roll-forming process. It requires TDF corners and cleats for assembly. TDF is widely used in North America and offers good structural performance for ducts up to 1.5m width.
TDC (Transverse Duct Connector): The TDC system uses a separate connector profile that is clipped onto the duct end. It provides a stronger connection and is preferred for larger duct sizes and higher pressure systems. TDC is common in Europe and growing in popularity globally.
Key Differences: TDF is faster to produce on-machine but requires more corner hardware. TDC offers superior sealing and structural integrity but adds material cost. For most standard commercial HVAC applications, TDF is sufficient and cost-effective. For high-pressure or large-format industrial ductwork, TDC is the better choice.
Compatibility: TDF and TDC are not interchangeable — you must commit to one system for a given project. Many fabricators maintain both flange formers to serve different customer requirements.
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