01. Ducting :
Ducts are conduits or passages used in heating, ventilation, and air conditioning (HVAC) to deliver and remove air. … A duct system is also called duct work. Planning (laying out), sizing, optimizing, detailing, and finding the pressure losses through a duct system is called duct design. Ducting is an approach to air management that uses a series of metal or plastic pipse to
carry heated or cooled air from one place to another.
The most common are: sheet metal, fiberglass lined, fiberboard, and flex-line air ducts.

• Sheet Metal Air Ducts. The most common type of ridged air duct is constructed of galvanized steel or aluminum.
• Fiberglass Lined Air Ducts.
• Fiberboard Air Ducts.
• Flexible Air Ducts.

Within these three classifications of duct work, there are two major types of ducts – flexible and sheet metal. Sheet metal ducts come in both rectangular and cylindrical shapes, and are generally more reliable and durable than flexible ducts.