Panel seal for an air handling unit

An air handling system containing sections each having a framework made up of tubular structural elements defining each perpendicularly aligned openings each of which shares a common structural element with its neighbors. The openings are closed by panels that are latched into the openings. Said assemblies are installed around the perimeter of each rectangular opening. Each assembly includes a rigid plate having two bulb seals extending along opposite edges of the plate that are coextruded with the plate. The plate is mounted at about a 45° angle along an inside corner edge of each commonly shared structural element so that a seal on one side of the plate services one opening while the other seal services the adjacent opening. The ends of the seals are mitered and the plate is inserted into a slot formed in molded corner retainers that support the structural elements in assembly. The mitered corners of the four seals surrounding an opening are placed in abutting contact to create a positive seal about each opening in the modular section.