F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
F16L23/00—Flanged joints
F16L23/16—Flanged joints characterised by the sealing means
F16L23/18—Flanged joints characterised by the sealing means the sealing means being rings
F16L23/20—Flanged joints characterised by the sealing means the sealing means being rings made exclusively of metal