API Specification 6A is the industry standard for wellhead and Christmas tree equipment used in oil and gas production. The 21st Edition was released in November 2018 and became effective for the API Monogram Program on November 1, 2019. 📥 Official Access and PDF Links
The 21st edition represented a "total revision" and reorganization of the standard: American Petroleum Institute | API api specification 6a 21st edition pdf link
Accuris Standards Store: An authorized third-party retailer for purchasing the standard and its redline versions. Major Changes in the 21st Edition API Specification 6A is the industry standard for
: The document was completely reorganized with revised sizing tables and the removal of outdated sections like repair/remanufacturing (now covered under API 6AR). Latest Errata and Addenda Major Changes in the 21st Edition : The
The 21st Edition moved away from its previous joint development with ISO 10423, allowing API to tailor requirements specifically to evolving industry needs. Key updates include: