Segmented bends are designed for spiral ducts. They are made of 5 segments; the bends in diameters of DN 1120 mm and greater are made of 6 segments. The segments are fastened by hemming and seaming. BSDL bends feature sealed inside surfaces of the hemmed seams and double EPDM gaskets to provide air tightness class D according to EN 12237 for ventilation and heat recuperation systems.
The bending radius is ca. 1.5D to reduce the pressure loss and the flow resistance along the ventilation system. The bending radius can be increased to 3D or 4D on request to further improve the flow resistance.