Identification

• Duct work systems use supply ducts, which push the warm or cool air, and return ducts, which pull air from the rooms for retreatment. There are different layouts for duct work, the most popular being an extended plenum where a large trunk is extended with supply lines running off of this trunk at right angles.
  
  

Types

• There are different types of duct work such as rectangle duct, radial duct, and most recently flexible duct. Each has its own pros and cons, such as durability, reduced fittings needed and insulation.
  
  

Function

• The sizing of duct work is determined by the size of the furnace unit, the length the air has to travel and the number of supply lines branching off the plenum.
  
  

Considerations

• When laying out the duct work, structural considerations must be made, such as whether supply lines and returns can navigate the framing members and possible structural steel in a home.
  
  

Warning

• Working with sheet metal can be dangerous and so the proper hand and eye protection must be used at all times.