New MSS Standards Published Recently

Source: MSS

The Manufacturers Standardization Society (MSS) of the Valve and Fittings Industry has released a number of new or revised standards since March of this year.

SP-83-2025, Class 3000 and 6000 Pipe Unions, Socket Welding and Threaded (Carbon Steel, Alloy Steel, Stainless Steels, and Nickel Alloys) was released. This standard practice contains an envelope and other essential dimensions, finish, tolerances, testing, marking, material and minimum performance requirements for forged carbon steel, alloy steel, stainless steel, nickel alloy pipe unions, socket welding and threaded ends. SP-83 continues to be maintained under the consensus of MSS Technical Committee 105, Forged Steel Fittings.

SP-97-2025, Integrally Reinforced Forged Branch Outlet Fittings: Socket Welding, Threaded, and Buttwelding Ends was released on March 19. This standard practice includes essential dimensions, finish, tolerances, testing, marking, material and minimum strength requirements for 90° and 45° integrally reinforced forged branch outlet fittings of buttwelding, socket welding and threaded types.

ANSI/MSS SP-55-2025, Quality Standard for Iron and Steel Castings for Valves, Flanges, Fittings, and Other Piping Components, Visual Method for Evaluation of Surface Irregularities has been approved by the American National Standards Institute (ANSI) as a revised American National Standard (ANS) and published by MSS on April 28, 2025. This standard practice is intended to supplement requirements of the ASTM Standard Specifications identified in Section 2, by providing a collection of reference photographs typical of the various surface irregularities common to iron and steel pressure castings, which illustrate generally acceptable and generally rejectable quality.  Table 1 of Section 7 is provided to show MSS interpretation as to the relationship between this Standard Practice and the levels of surface quality illustrated by the comparators and the associated photographs of the Castings Technology International (CTI), “Comparators for the Definition of Surface Quality of Steel Castings”. SP-55 continues to be maintained under the consensus of MSS Technical Committee 304, Quality Standards.

SP-162-2025, Design Requirements for Actuator-to-Valve Mounting Components was announced on April 30. SP-162-2025 provides requirements for actuator-to-valve mounting components, including design constraints, allowable stresses, marking and performance criteria. SP-162 continues to be maintained under the consensus of MSS Technical Committees 408, Valve Actuators.

SP-91-2025, Guidelines for Manual Operation of Valves has been revised and published by MSS. This standard practice provides guidelines for the operation of manually actuated valves as affected by the valve operator’s input. SP-91 continues to be maintained under the consensus of MSS Technical Committees 306, Valve Operation.

These standards documents are available for purchase from MSS, and more information about the association can be found on the website, msshq.org.