MSS SP-117-2023 ✓ Most Recent

1.1 This Standard Practice covers requirements for design, materials, fabrication, installation, qualification, examination, testing, marking, ordering, and shipment of metal bellows and/or bellows assemblies to be installed in manual and automated on-off globe and gate valves.

1.2 This Standard Practice is applicable to metal bellows used in conjunction with steel globe and gate valves which otherwise satisfy the requirements of both API standards (such as API 600, API 602, and API 603) and ASME B16.34. Such standards are referred to herein as the “parent” valve standards.

1.3 This Standard Practice does not apply to non-metallic bellows or bellows made of low melting point materials such as brass, phosphor-bronze, or similar materials.

1.4 Except where specifically noted in the text of this Standard Practice, the requirements here are not intended to supersede or replace those requirements of the parent valve standard. This Standard Practice specifies additional requirements for those valves utilizing bellows seals.

1.5 It is the responsibility of the bellows valve manufacturer to ensure compliance with this Standard Practice.