The KF standard is predominantly used for applications ranging from rough to high vacuum, with pressures up to 10E-9 mbar (100 nPa) or peak pressures up to 20 bar (2 MPa), depending on the flange diameter, seal material, and the geometry of the center ring. Inner center rings are utilized for vacuum applications, while outer center rings are preferred for overpressure situations. Combination rings are also available for scenarios where both vacuum and overpressure conditions may occur.

Using steel KF flanges with aluminum edge-type seals, the vacuum range can be extended to 10E-11 mbar (1 nPa), with a peak pressure capacity of up to 50 bar (5 MPa)