RUMORED BUZZ ON FLEXIBLE DUCT

Joints of duct methods shall be produced considerably airtight through tapes, mastics, liquid sealants, gasketing or other accredited closure units. Closure methods used with rigid fibrous glass ducts shall adjust to UL181A and shall be marked181A-P for strain-delicate tape, 181A-M for mastic or 181 A-H for heat-delicate tape. Closure methods made