API 6D – Specification for Pipeline Valves
API 6D specifies requirements and provides recommendations for the design, manufacturing, testing and documentation of ball, check, gate and plug valves for application in pipeline systems meeting the requirements of ISO 13623 for the petroleum and natural gas industries.
API 6D is not applicable to subsea pipeline valves, as they are covered by a separate International Standard (ISO 14723).
API 6D is not applicable to valves for pressure ratings exceeding PN420 (Class2500).