This MSS Standard Practice applies to small valves and manifolds developed for and predominantly used in instrument, control and sampling piping systems. This standard applies to instrument valve designs including but not limited to needle valves, packless valves, ball valves, plug valves, check valves and manifold valves.
Instrument valves are generally of proprietary design.
This standard is not intended to define or limit designs, construction, performance, envelope dimensions, or valve types.