MSS SP-120-2024 PDF

This Standard Practice is applicable to isolation valves that use flexible graphite compression packing stem sealing to achieve reduced or low emissions.

This Standard Practice encompasses dimensions and tolerances applicable to ASME B16.34 gate and globe valves designed with rising non-rotating and rising rotating stems. Quarter turn valve designs are outside the scope of this Standard Practice.

This Standard Practice applies to valves in which a flexible graphite compression packing assembly is used as the primary stem-sealing system.

Valves that include a lantern ring as part of its packing system, and bonnetless valves with split glands, are outside the scope of this Standard Practice.

Applications requiring specific cleanliness levels such as those intended for oxygen service are outside the scope of this Standard Practice.

Control valve applications requiring high cycle life are outside the scope of this Standard Practice.

Applications requiring high purity levels such as those intended for nuclear service are outside the scope of this Standard Practice.

This Standard Practice is not intended to apply to valves developed for and predominantly used in instrument piping systems (see MSS SP-99 and MSS SP-105).