Access door construction

摘要

An access door which covers and seals an access opening in a ventilating duct. The edge of the access opening is strengthened by a dual density gasket having a U-shaped hard portion which is applied to the duct edge. A softer sealing element projects from the hard portion of the gasket and is sealed against from the inside by the door so that the duct pressure enhances the seal. The door is a sheet metal panel having a stepped configuration and a peripheral flange for contact with the seal elements. The door is held over the access opening by retainer straps having adjustment screws.