Why use Insulation facing as Vapor barrier?
In terms of HVAC Ductworks functionality, Insulation facing is often used to limit vapor drive with the ultimate goal of preventing condensation.
Perm rating is a standard measure of the water vapor permeability of a material. The higher the number, the more readily water vapor can diffuse through the material. A perm rating of less than 0.1 is considered a Class I impermeable vapor retarder, which is also considered a vapor barrier.
Foil scrim kraft (FSK)
Poly scrim kraft (PSK)
All service jacket (ASJ)
All of above insulation facing Perm rating less than 0.1 that meet the Class I impermeable vapor retarder. So the Insulation facing suitable for a wide variety of applications, it can be used as vapor barrier layer for insulation materials, with good aging resistance and corrosion resistance.