Joints of duct devices shall be created substantially airtight by way of tapes, mastics, liquid sealants, gasketing or other accepted closure programs. Closure devices applied with rigid fibrous glass ducts shall comply with UL181A and shall be marked181A-P for stress-delicate tape, 181A-M for mastic or 181 A-H for warmth-sensitive tape. https://normann109ems7.wiki-jp.com/user