Acudor Duct Access Doors for High Pressure Ducts are designed to provide convenient, economical access to high pressure ducts. These doors are for use in high pressure ducts up to 8" static pressure. Pressure rated to 8" W.G. with leakage no greater than 2 CFM per sq. ft. or less. The 5/8" notched knock over tabs on the inside of the frame provide for easy installation.