MSS - Manufacturers Standardization Society of the Valve and Fittings Industry.
Scope
The purpose is to provide a Standard Practice for metallic valves used in fuel gas piping systems which are manually operated both above and below ground. This Standard Practice covers Metallic Gas Distribution Valves designed for operation at any pressure from 0 psig to a maximum of 285 psig@ at operating temperatures ranging from -20??to 150?? and from sizes 1/2 to 12 NPS.