Abstract: Described are isolation valves, and chamber systems incorporating and methods of using the isolation valves. In some embodiments, an isolation valve may include a valve body and a flapper assembly. The valve body may define a first fluid volume, a second fluid volume, and a seating surface. The flapper assembly may include a flapper disposed inside the valve body having a flapper surface complimentary to the seating surface. The flapper may be pivotable within the valve body to a first position such that the flapper surface may be away from the seating surface to allow fluid flow between the first fluid volume and the second fluid volume. The flapper may be pivotable within the valve body to a second position such that the flapper surface may be proximate the seating surface to form a non-contact seal to restrict fluid flow between the first fluid volume and the second fluid volume.