UL 181C:2020 PDF Download

1 Scope

1.1 These requirements apply to non-metal accessories, such as collars and sleeves, used to join or attach flexible air ducts and air connectors that comply with the requirements of UL 181, Factory-Made Air Ducts and Air Connectors. The air ducts and air connectors with their joining accessories are intended to be installed in accordance with the International Mechanical Code (IMC), International Residential Code (IRC), Uniform Mechanical Code (UMC), and/or NFPA 90A, Standard for the Installation of Air-Conditioning and Ventilating Systems.

1.2 This Outline is not intended for metal joining accessories, such as collars and fittings. Requirements for these products are found in SMACNA HVAC Duct Construction Standards – Metal and Flexible, 3rd edition, 2005.

1.3 These non-metal accessories, such as collars and sleeves, have not been evaluated for use with rigid factory made air ducts and connectors.

1.4 These non-metal accessories, such as collars and sleeves, have not been evaluated for use with sheet metal ducts that comply with SMACNA HVAC Duct Construction Standards – Metal and Flexible, 3rd edition, 2005.

1.5 Where the use of these non-metal joining accessories present a conflict with the accompanying installation instructions of the flexible air ducts, then those instructions are intended to govern the installation.