FLEXIBLE DUCT CAN BE FUN FOR ANYONE

Joints of duct units shall be designed substantially airtight through tapes, mastics, liquid sealants, gasketing or other approved closure units. Closure devices employed with rigid fibrous glass ducts shall adjust to UL181A and shall be marked181A-P for force-sensitive tape, 181A-M for mastic or 181 A-H for warmth-delicate tape. Closure methods us