ABSTRACT
Air is distributed in a building by means of connected individual duct sections that make up the ductwork. The configuration of a ductwork is comparable to a tree with branches connected to the terminal unit. The fan is located at the air handling unit (AHU). In reality, ductwork forms a double-tree because the fan is in the middle of the supply and the return/outside air parts of the system. Duct leakage refers to the fact that the air inside a supply air duct is under a positive pressure. Duct insulation and sealing, especially insulated supply ducts delivering conditioned air within a building, save energy. The intent is to keep mechanically warmed or cooled air as close to a constant, desired temperature as possible and prevent the conditioned air from the escaping the duct system while it is being moved to spaces, where it is needed.
