The full form of MSS is the Manufacturers Standardization Society of the Valve and Fittings Industry. They are a non-profit technical association. Officially founded in the year 1924, the Manufacturers Standardization Society of the Valve and Fittings Industry (MSS) publishes various international codes and standards to ensure compliance, interoperability, safety, and operation of process piping systems for various industries like petroleum, petrochemical, food, beverage, and utility. The MSS standards mainly cover the following product segments:
Valves, Actuators, Valve modifications.
Pipe hangers.
Pipe fittings
Flanges
Seals, etc
With its 26 technical committees, MSS reviews and writes various useful industry standards. They have a wide range of participations including some of the most prestigious institutions like
American Society for Testing and Materials ASTM),
American Society of Mechanical Engineers (ASME),
American National Standards Institute (ANSI),
American Petroleum Institute (API),
American Waterworks Association (AWWA), and
the National Fire Protection Association (NFPA).
The Manufacturers Standardization Society of the Valve and Fittings Industry provides membership benefits to the member organizations including access to all their standards. Some of the standards and specifications developed by MSS are widely used in the piping industry. The standards developed by the MSS are provided with the term MSS followed by the term SP followed by the number and year of the latest publication (edition). Example; MSS SP-44-2019 or MSS SP-58-2018.
The following section will list the common MSS Standards that are extensively used in the Piping Industry.
List of MSS Standards
The following table lists some of the popular MSS standards:
Standard Marking System for Valves, Fittings, Flanges, and Unions
2018
MSS-SP-44
Steel Pipeline Flanges
2019
MSS-SP-55
Quality Standard for Steel Castings for Valves, Flanges, Fittings, and Other Piping Components – Visual Method for Evaluation of Surface Irregularities
2011
MSS-SP-58
Pipe Hangers and Supports – Materials, Design, Manufacture, Selection, Application, and Installation
2018
MSS-SP-75
High-Strength, Wrought, Butt-Welding Fittings
2019
MSS-SP-86
Recommended Rules and Guidelines for SI (Metric) Data in MSS Standards
2021
MSS-SP-92
Valve User Guide
2021
MSS-SP-96
Terminology for Valves, Fittings, and Their Related Components
2017
MSS-SP-138
Quality Standard Practice for Oxygen Cleaning of Valves and Fittings
2014
MSS-SP-144
Pressure Seal Bonnet Valves
2020
MSS-SP-6
Standard Finishes for Contact Faces of Pipe Flanges and Connecting-End Flanges of Valves and Fittings
2021
MSS-SP-9
Spot Facing for Bronze, Iron, and Steel Flanges
2018
MSS-SP-42
Corrosion-Resistant Gate, Globe, Angle, and Check Valves with Flanged and Butt Weld Ends (Classes 150, 300, & 600)
2013
MSS-SP-43
Wrought and Fabricated Butt-Welding Fittings for Low Pressure, Corrosion Resistant Applications
2019
MSS-SP-45
Bypass and Drain Connections
2020
MSS-SP-51
Class 150LW Corrosion Resistant Flanges and Cast Flanged Fittings
2021
MSS-SP-53
Quality Standard for Steel Castings and Forgings for Valves, Flanges, Fittings, and Other Piping Components – Magnetic Particle Examination Method
2021
MSS-SP-54
Quality Standard for Steel Castings for Valves, Flanges, Fittings, and Other Piping Components – Radiographic Examination Method
2013
MSS-SP-60
Connecting Flange Joints between Tapping Sleeves and Tapping Valves
2021
MSS-SP-61
Pressure Testing of Valves
2019
MSS-SP-65
High-Pressure Chemical Industry Flanges and Threaded Stubs for Use with Lens Gaskets
2019
MSS-SP-67
Butterfly Valves
2022
MSS-SP-68
High-Pressure Butterfly Valves with Offset Design
2021
MSS-SP-70
Gray Iron Gate Valves, Flanged and Threaded Ends
2011
MSS-SP-71
Gray Iron Swing Check Valves, Flanged and Threaded Ends
2018
Table 1: MSS SP Standards
Other MSS Standards
Other MSS SP standards are listed below:
MSS-SP-72-2010a: Ball Valves with Flanged or Butt-Welding Ends for General Service
MSS-SP-78-2011: Gray Iron Plug Valves, Flanged, and Threaded Ends
MSS-SP-79-2018: Socket-Welding Reducer Inserts
MSS-SP-80-2019: Bronze Gate, Globe, Angle, and Check Valves
MSS-SP-81-2021: Stainless-Steel or Stainless-Steel-Lined, Bonnetless, Knife Gate Valves with Flanged Ends
MSS-SP-83-2018: Class 3000 and 6000 Pipe Unions, Socket Welding, and Threaded (Carbon Steel, Alloy Steel, Stainless Steel, and Nickel Alloys)
MSS-SP-85-2011: Gray Iron Globe & Angle Valves, Flanged and Threaded Ends
MSS-SP-87-1991(R1996 – Reinstated 2011): Factory-Made Butt-Welding Fittings for Class I Nuclear Piping Applications
MSS-SP-88-2021: Diaphragm Valves
MSS-SP-91-2009: Guidelines for Manual Operation of Valves
MSS-SP-93-2020: Quality Standard for Steel Castings and Forgings for Valves, Flanges, Fittings, and Other Piping Components – Liquid Penetrant Examination Method
MSS-SP-94-2020: Quality Standard for Ferritic and Martensitic Steel Castings and Forgings for Valves, Flanges, Fittings, and Other Piping Components – Ultrasonic Examination Method
MSS-SP-127-2014a, Bracing for Piping Systems: Seismic-Wind-Dynamic Design, Selection, and Application
MSS-SP-128-2012, Ductile Iron Gate Valves
MSS-SP-129-2021, Copper-Nickel Fittings
MSS-SP-130-2013, Bellows Seals for Instrument Valves
MSS-SP-131-2017, Metallic Manually Operated Gas Distribution Valves
MSS-SP-132-2022, Compression Packing Systems for Instrument Valves
MSS-SP-134-2012, Valves for Cryogenic Service, including Requirements for Body/Bonnet Extensions
MSS-SP-135-2021, High-Pressure Knife Gate Valves
MSS-SP-136-2020, Ductile Iron Swing Check Valves
MSS-SP-137-2020, Quality Standard for Positive Material Identification of Metal Valves, Flanges, Fittings, and Other Piping Components
MSS-SP-139-2014, Copper Alloy Gate, Globe, Angle, and Check Valves for Low Pressure/Low-Temperature Plumbing Applications
MSS-SP-140-2021, Quality Standard Practice for Preparation of Valves and Fittings for Silicone-Free Service
MSS-SP-141-2012, Multi-Turn and Check Valve Modifications
MSS-SP-142-2012, Excess Flow Valves for Fuel Gas Service, NPS 1½ through 12
MSS-SP-143-2018, Live-Loaded Valve Stem Packing Systems
MSS-SP-145-2013, Metal Ball Valves for Low Pressure/Low-Temperature Plumbing Applications
MSS-SP-146-2019, High-Pressure Knife Gate Valves: Iron and Ductile Iron, Lug-, Wafer-, and Flange-Type
MSS-SP-147-2014, Quality Standard for Steel Castings Used in Standard Class Steel Valves – Sampling Method for Evaluating Casting Quality
MSS-SP-148-2019, Low-Pressure Flanged or Lugged Carbon Steel and Iron or Ductile Iron, Cast or Fabricated, Bonnetless, Knife Gate Valves without Liners
MSS-SP-149-2018, Preformed Elastomeric and Polytetrafluoroethylene (PTFE) V-Ring Packing Sets for Waterworks Valves
MSS-SP-150-2019, Valves for Use in Hydrogen Peroxide Service
MSS-SP-151-2021, Pressure Testing of Knife Gate Valves
MSS-SP-152-2022, Knife Gate Valves for Double Block and Bleed
MSS-SP-153-2017, Modification of New Water Works Valves
MSS-SP-154-2018, Low-Pressure Knife Gate Valves for Double Block and Bleed
I am a Mechanical Engineer turned into a Piping Engineer. Currently, I work in a reputed MNC as a Senior Piping Stress Engineer. I am very much passionate about blogging and always tried to do unique things. This website is my first venture into the world of blogging with the aim of connecting with other piping engineers around the world.
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