Air ducts are basically all manufactured out of sheet metal. However, the insulation which is constructed later can be made of various types of material. Here are some of the basic materials that are typically used for the inter-lining of commercial and residential air duct systems.
Phenolic and polyurethane materials are preinstalled in most ductwork. They form a panel that is made of foam that has aluminum plating on both sides. The dimensions of the foil may vary depending on whether the ducts are needed for indoor or outdoor use. Outdoor ducts usually have much greater mechanical features. These specific ducts are composed of steel sheets that are coated with aluminum alloy. The laminate may consist of fiber polymer or another waterproof coating.
Panels that are made of fiberglass are made for thermal use. The inside of the ducts absorbs noise making the HVAC system run quietly. Fiberglass panels are designed with a special knife to trim out grooves in a particular manner without penetrating all the way trough. This enables the surface to act as if it was a hinge that is capable of being folded into sections forming a rectangle. The remaining ends are then stapled and wrapped by aluminum tape.
Fabric Duct Panels
Fabric duct panels are manufactured of polyester material. This type is known to give a more proficient air flow than the common duct system. These ducts were not really intended to be used as the typical duct would be. Air distribution is initially their only purpose. Most people think of them as ducts since they are usually used as a replacement for metal air duct systems.