Instructions / Assembly

What material should I use to support flexible duct?
Per NFPA 90A and 90B, supplementary material used with air ducts shall meet
the requirements of Class 1 when tested to UL 723 (Surface Burn
Characteristic Testing), i.e. 25 Flame Spread & 50 smoke developed maximum.
Per ADC, any strapping material in contact with the flexible duct shall be 1-1/2
inch wide minimum and be applied at intervals not to exceed 4 feet (6 feet for
vertical supports). Sag should not exceed ½ inch per foot of support spacing.