1.1 These requirements apply to materials for the fabrication of air duct and air connector systems for use in accordance with the Standards of the National Fire Protection Association for the Installation of Air-Conditioning and Ventilating Systems, NFPA No. 90A, and the Installation of Warm Air Heating and Air-Conditioning Systems, NFPA No. 90B. 1.2 The air ducts and air connectors covered by these requirements include preformed lengths of flexible or rigid ducts, materials in the form of boards for field fabrication of lengths of rigid ducts, and preformed flexible air connectors. 1.3 For the purpose of these requirements, air ducts and air connectors are classified as follows: Class 0 - Air ducts and air connectors having surface burning characteristics of zero. Class 1 - Air ducts and air connectors having a flame-spread index of not over 25 without evidence of continued progressive combustion and a smoke-developed index of not over 50. This new edition of ANSI/UL 181 includes wording, organizational, miscellaneous editorial revisions, and the following: 1. Revision to material construction specifications. 2. Clarification of sample selection practices for the Surface Burning Characteristics Test. 3. Deletion of references to the withdrawn standard, UL 214, the Standard for Tests for Flame Propagation of Fabrics and Films and addition of a reference to NFPA 701, Standard Methods of Fire Tests for Flame Propagation of Textiles and Films. 4. Revisions to gas specifications used in the Burning Test. 5. Revisions to mold and spores requirements in the Mold Growth and Humidity Test. 6. Clarification to the Low and High Temperature Test. 7. Addition of installation instructions to include a reference to UL 181A, the Standard for Closure Systems for Use With Rigid Air Ducts and Air Connectors and requirements for pressure-sensitive tapes and mastic products. 8. Revisions to several conversions to truncate all metric measurements to the whole number or to the tenth.
UL 181-2005 history
1970UL 181-2021 Factory-made air ducts and air connectors
2017UL 181 BULLETIN-2017 UL Standard for Safety Factory-Made Air Ducts and Connectors (COMMENTS DUE: April 10@ 2017)
2013UL 181 BULLETIN-2013 UL Standard for Safety Factory-Made Air Ducts and Connectors (COMMENTS DUE: APRIL 22@ 2013)
2013UL 181-2013 Factory-made air ducts and air connectors
2012UL 181 BULLETIN-2012 UL Standard for Safety Factory-Made Air Ducts and Connectors (COMMENTS DUE: May 09@ 2012)
2008UL 181 BULLETIN-2008 UL Standard for Safety Factory-Made Air Ducts and Connectors COMMENTS DUE: MAY 30, 2008