The outside of fiberboards contains a foil covering that serves as both equally an air and dampness barrier. By themselves, fiberboard ducts are great insulators and don't have to have any further insulation. As their title suggests, rigid ducts are inflexible and don’t have any risk of bends or kinks https://lukasdztqg.corpfinwiki.com/9008936/5_simple_statements_about_pu_ducting_tdi_explained