VapAir Seal MD Air and Vapor Barrier is used for direct application over metal decks when insulation is to be mechanically fastened and is suitable for all internal conditions, including very high humidity. They quickly get install and creates an air- and vapor-tight seal. Its enhanced vapor resistance is sufficient to accommodate extreme internal conditions such as buildings containing wet industrial processes, swimming pools, breweries, sports halls, kitchens and bathrooms etc. VapAir Seal MD consists of a reinforced composite aluminum foil with a tenacious self-adhesive SBS backing and removable poly release film.