Circular spiral ducts are manufactured in diameters from 80 to 1600mm. Spiral ducting is available with a material thickness from 0.4 to 1.8 mm, from diameter 250mm they are provided with corrugations/exterior grooves for better tightness and rigidity under negative pressure.
Circular ducting are manufactured from galvanized (standard), stainless steel, aluminium sheet, they meet requirements for air tightness class D certified by EN 12237.
