NC Filtration’s™ HEPA Filters are housed using 5/8″ particle board framing glued together using a fire-retardant, rubber bade adhesive and urethane sealant providing a positive seal and rigid enclosure for the media pack. A closed-cell, neoprene gasket is placed on the downstream side of each unit. Each filter is constructed from one continuous sheet of high strength, waterproof glass microfiber paper, sealed to the frame on all four edges. Corrugated aluminum media separators are placed between each pleat (18 pleats/ft.) of media to prevent the pleats from touching, allowing air to pass through with minimum of resistance.