Joints of duct systems shall be made considerably airtight by the use of tapes, mastics, liquid sealants, gasketing or other authorized closure programs. Closure systems applied with rigid fibrous glass ducts shall comply with UL181A and shall be marked181A-P for tension-sensitive tape, 181A-M for mastic or 181 A-H for heat-delicate https://derekc109kxj3.activoblog.com/profile