Air Duct Lining : A material such as an adhesive, insulation, a coating(s), or film used to line the inside surface of an air duct, fan casing, or duct plenum
NFPA 90A Standard for the Installation of Air-Conditioning and Ventilating Systems, 2009 ed. http://catalog.nfpa.org/NFPA-90A-Standard-for-the- Installation-of-Air-Conditioning-and-Ventilating-S ystems-Prior-Years-P4155.aspx, (Std: Instll of AC & Vent Sys - Amer) {235 NFC}