Sheet Metal & Air Conditioning Contractors’ National Association

Papers and Guidelines


These papers are copyrighted by SMACNA. SMACNA grants single user permission to download and use. Any further use in part or in whole requires permission.


Rooftop Ductwork – Round or Rectangular?

This technical resources bulletin discusses the differences between round and rectangular duct types, and factors to consider when choosing the appropriate duct type for rooftop ductwork applications.