This document defines the requirements for the design, manufacturing, quality control, assembly, testing, and documentation of ball, check, gate, plug, and axial on off valves for application in subsea pipeline systems for the petroleum and natural gas industries. This document applies to ASME Class 150, 300, 600, 900, 1500, and 2500 valves intended for use in subsea pipelines. Use of these valves for any other purpose is outside the scope of this document. This document is a supplement to API 6DSS, 3rd edition (2022), the requirements of which are applicable with the additions specified in this document.