Joints of duct units shall be made substantially airtight through tapes, mastics, liquid sealants, gasketing or other approved closure systems. Closure methods utilised with rigid fibrous glass ducts shall adjust to UL181A and shall be marked181A-P for tension-sensitive tape, 181A-M for mastic or 181 A-H for heat-delicate tape. Closure systems https://aluminium-foil-insulation81368.blogofoto.com/66476166/the-single-best-strategy-to-use-for-aluminium-foil-insulation