Class 1 flexible uninsulated duct with polymer core and surrounding fire resistant barrier layer and method of use

A flexible uninsulated duct that meets at least some or all of Underwriter Laboratories (UL) 181 Class 1 duct standards comprising:

• a polymer core having a helical wire as a part thereof, the polymer core having first and second opposing surfaces;
• and
• a fire resistant barrier layer having opposing first and second surfaces, one of the first and second surfaces of the fire resistant barrier layer facing one of the first and second surfaces of the polymer core, one of the first and second surfaces of the fire resistant barrier layer or one of the first and second surfaces of the polymer core forming an inside surface of the flexible uninsulated duct that forms a channel for conditioned air flow, wherein either the fire resistant barrier layer forms the channel or the fire resistance barrier layer is exposed as an outer surface of the flexible uninsulated duct, and
• (1) portions of the fire resistant barrier layer forming an overlap as either a longitudinal seam or a spirally wound seam, a combination of at least first and second adhesives between overlapping portions of the fire resistant barrier layer, the first adhesive as a hot melt adhesive in an effective amount to immediately bond the overlapping portions together, the second adhesive as a high temperature adhesive in an effective amount to maintain the bond between the overlapping portions when the longitudinal seam or spirally wound seam is subjected to a flame penetration test according to the UL 181 Class 1 duct standard;
• or
• (2) portions of the fire resistant barrier layer forming an overlap and either longitudinal seam or a spirally wound seam, a combination of at least first and second adhesives between overlapping portions of the fire resistant barrier layer, the first adhesive as a hot melt adhesive in an effective amount to immediately bond the overlapping portions together, the second adhesive as a cold glue in an effective amount to maintain the bond between the overlapping portions when the longitudinal seam or spirally wound seam is subjected to a high temperature test according to the UL 181 Class 1 duct standard.