API Spec 6A is an international standard (ISO 10423) for wellhead and Christmas tree equipment in the petroleum and natural gas industry. It specifies requirements for:
Design, materials, testing, inspection, welding, and certification.
Covered equipment: Valves (gate, check, choke), casing/tubing heads, connectors, actuators, and safety systems.
Pressure classes: 2000 - 20,000 PSI.
Product Specification Levels (PSL): Defines rigor of requirements (PSL 1 - 4, 3G), with PSL 3G mandating enhanced gas tests.
Temperature ratings: e.g., Class "U" (-18oC to 121oC).
Critical tests include hydrostatic shell/seat tests and optional fire resistance per API 6FA.
It ensures safety and interoperability in high-pressure drilling/production environments.
