API Spec 6D is the international standard for pipeline valves in petroleum and natural gas transportation systems. It specifies requirements for the design, manufacturing, testing, and inspection of gate valves, ball valves, check valves, and plug valves with:
Flanged or welded ends.
Pressure classes PN16 to PN420 (ASME B16.34 equivalent) and sizes DN15 to DN1200.
Critical features like full-bore/reduced-bore design, structural length (for interchangeability), and pressure- temperature ratings.
Key requirements include:
DBB (Double Block and Bleed) or DIB (Double Isolation and Bleed) capabilities for safe maintenance.
Rigorous pressure testing (shell, seat leakage) with durations scaled to valve size.
Material standards, anti-corrosion measures, and fire-safe design.
Marking and documentation for traceability.
The standard ensures valve reliability and safety in high-pressure pipeline applications.
