MSS Released Revised Standard for SP-51-2021

03 May 2021

The Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry recently announced 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 decided that a commercial need remained for flanges and flanged fittings of reduced weight. This SP 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. 

Image credit: The Manufacturers Standardization Society (MSS)