API 6D Check Valves
What API 6D requires for check valves — applicability, key and testing requirements, the alternative standards, and compliant supply with full certification.
What does API 6D require for check valves?
API 6D (Specification for Pipeline and Piping Valves, American Petroleum Institute (API)) sets the design, material and testing requirements for check valves in its scope. API 6D is the most widely cited standard for pipeline and piping valves in the oil and gas industry. It covers design, manufacturing, testing, inspection, and documentation requirements for ball valves, gate valves, check valves, plug valves, and through-conduit gate valves used in petroleum and natural gas pipelines. API 6D compliance is mandatory for all major oil companies including Saudi Aramco, ADNOC, ONGC, IOCL, and GAIL.
Applicable Pressure Classes
Key Requirements
- Body and bonnet wall thickness per pressure class and temperature
- Body cavity relief (BCR) provision for thermal expansion of trapped fluid
- Anti-static device between ball/disc and stem
- Emergency sealant injection fittings on stem and body seats
- Double-block-and-bleed (DBB) capability for isolation service
- Fire-safe design per API 607 or API 6FA (when specified)
- Pigging capability - full-bore (ID ≥ pipe bore) for piggable pipelines
- Positive material identification (PMI) of all pressure-containing parts
- Low-emission stem packing per ISO 15848-1/2 (when specified)
Testing Requirements
- Shell test: 1.5× rated pressure, 15 minutes minimum, zero leakage
- Seat leakage test: 1.1× rated pressure, per API 598 leak class
- Back seat test (if applicable): 1.1× rated pressure
- Anti-static device test: <10 ohm resistance
- Torque measurement at maximum differential pressure
- Hydrostatic test certificate required for all valves
Alternative Standards for Check Valves
Other standards that also govern check valves — useful for spec cross-acceptance.
Related Standards
Connected Engineering
Need API 6D check valves?
We supply API 6D-compliant check valves with full certification — share your size, class and service for a 24-hour quote.