This Standard covers only manually operated metallic valves in nominal pipe sizes 2 1/2 through 12 having the inlet and outlet on a common center line, which are suitable for controlling the flow of gas from open to fully closed, for use in distribution and service lines where the maximum gage pressure at which such distribution piping systems may be operated in accordance with the Code of Federal Regulations (CFR), Title 49, Part 192, Transportation of Natural and Other Gas by Pipline; Minimum Safety Standard, does not exceed 125 psi (8.6 bar). Valve seats, seals and stem packing may be nonmetallic.