Rectangular ducts are fabricated on automated lines from galvanized or stainless steel sheets, thickness ranges from 0.5 mm to 1.5 mm. Standard sizes range up to 2500 mm × 2000 mm. Connection methods include TDF flange, angle steel, or cleat systems. Inner stiffeners can be added for large sizes to ensure rigidity.
The smooth internal surface reduces energy consumption, while precise manufacturing ensures Class C or D sealing according to EN 1507. Widely applied in energy, automotive, shipbuilding, and commercial HVAC projects.