Many different concepts are used in the fabrication of ductwork for ven­tilation, air conditioning, and heating systems. Practices vary throughout the world. The important factors to be considered in manufacturing ducts are:

  • Satisfactory air-tightness of completed duct
  • Vibration-free operation
  • Even flow of air without undue pressure loss in system
  • Structural soundness to serve the purpose of conducting heated or cooled air within the system, with a minimum of tur­bulence, and at levels where comfort will not be reduced within the areas to be ventilated