The Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry announces that SP-51-2021, Class 150LW Corrosion Resistant Flanges and Cast Flanged Fittings, has been revised and published by MSS.
Standard Practice (SP)-51 has served as an industry norm for over 72 years! The subject matter of this Standard Practice was formerly part of MSS SP-42 until it was re-written and SP-42 now covers valves only. The committee had decided that a commercial need remained for flanges and flanged fittings of reduced weight. This Standard Practice specifies a series of cast austenitic stainless-steel flanged fittings and austenitic stainless-steel flanges of reduced weight with mating dimensions for assembly with ASME B16.5, Class 150 flanges, but identified as Class 150LW (Light Weight) and limited to use at reduced pressure-temperature ratings. SP-51 continues to be maintained under the consensus of MSS Technical Committee 110, Steel Flanges and Flanged Fittings.
The revised Standard Practice, MSS SP-51-2021, is now available from authorized U.S. and global distributors. It has been published in an electronic version (PDF) and book format.