Ductwork for dust collection systems are available in 5-feet and 10-feet sections. This 10-foot Steel dust pipe can be purchased in various diameters ranging from 4 inches up to 20 inches. Spiral dust pipes are made of 24 gauge galvanized steel. The interlocking seams and spiral shape of the dust pipe allows it to be stronger and more rigid than smooth ductwork. Spiral construction of steel dust pipes reduces the need for joints and hangers due to its structural strength.