When vacuum system pressures are in the positive pressure range, it is recommended that over pressure rings are used. The ISO-KF flange over pressure rings are installed differently by size. The NW16, NW25, and NW40 ISO-KF over pressure rings are installed over the two ISO-KF flanges. The NW10 and NW50 ISO-KF over pressure rings are installed between the two flange faces. The clamp is installed around all items to secure the assembly.

The International Standards Organization has defined the interface dimensions of ISO-KF vacuum flanges allowing the interchanging of components that conform to the ISO-KF standard. The ISO-KF flange system provides is a modular building block method for creating a vacuum systems. Since component dimensions are standardized, elbows, tees, crosses or valves for a given flange size can be interchanged. The flanges are sexless and the seal is symmetrical allowing components to be rotated. By using ISO-KF standard components, vacuum system assembly is quick and cost effective.

ISO-KF vacuum flange components are joined by inserting a centering ring seal between the two flange faces, then securing the assembly with a flange encompassing clamp. There are a variety of flange clamp choices available. The wing-nut flange clamp is hand tightened until metal contact is felt. The toggle flange clamp is convenient and easy to use and provides enough sealing force to fully compress the O-Ring, so that the flanges and the centering ring are metal to metal. The self-adjusting clamp locks in a positive method making it ideal when clamp must be removed frequently, like leak testing or gauge calibration. Bulkhead flange clamps attach an ISO-KF flange directly to a chamber or base plate. The two-part, bolted clamp fits over the flange with a centering ring assembly used between the flange and the opening.