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API Specification 6A, 21st Edition

We are pleased to announce the publication of the 21st edition of Specification 6A, Wellhead and Tree Equipment. This new edition provides technical updates that have reached consensus within API’s Subcommittee on Valves & Wellhead Equipment and will now give industry consistent practices in these respective areas of the standard. These updates are reflective of API’s standards program mission to provide a forum for development of consensus-based industry standards, and technical cooperation to improve the industry’s safety performance and competitiveness.

Key Changes:

Revision of the document will include:

  • A complete reorganization of the document—quality requirements are now grouped by specific activity and not by PSL, making it easier to determine the specific requirements for all PSLs in one location and not spread throughout the document. 
  • Uniformity in the layout of the product-specific section.
  • A total revision of all of the sizing tables, including associated figures, to allow for clearer understanding of the requirements. The tables exist as a full set in SI (metric) units and as a separate, exact set in USC (imperial) units.
  • Uniform use of product terms throughout the document.
  • Revision of the annexes:
    • Incorporation of annexes, in the body of the document (former Annex L and Annex O);
    • Former Annex J will be published as a new document, 6AR; former Annex H will be published within TR6RT; and former Annex I will be deleted in lieu of fully referencing 6AV1;
    • Former Annex E and Annex N were withdrawn as they are no longer needed/applicable to the document.
  • Addition of a new product (proposed for monogramming), boarding shutdown valves, developed with support of the regulatory community. The casing and tubing hangers product line is better defined for slip and mandrel hangers, two separate products. So, in effect, there will be three new products.
  • Removal of fluid sampling devices.
  • Integration of tubing head adapter requirements into overall head requirements for a more integrated product.
  • Required minimum PSL depending on the pressure rating and material class. Revised PSL 4 to target critical service equipment.
  • Heat treatment requirements now normative.
  • Removal of PR1 from design validation annex.
  • Addition of pressure boundary qualification requirements.
  • Creation of a new section on records and records control.
  • Factory acceptance testing (FAT) removed from the quality section; section reorganized and requirements presented in a more logical order.
  • Marking requirements now target specific products and not product families to better target specific marking needs.
  • Required minimum 20E and 20F BSL for bolting.

Effective Date and Program Implications

The API Monogram Program effective date will be November 1, 2019.

Current licensees shall ensure that products manufactured on and after November 1, 2019 meet the requirements of API 6A, 21st edition in order to be monogrammed.

Also, effective November 1, 2019, API 6A audits will be conducted to the 21st edition of the document.

To Purchase

Specification 6A is available on API’s new Compass platform. A Compass subscription gives you organization-wide, 24/7 access to all of the API standards and specifications you need to ensure safety, compliance, and interoperability. With a subscription on Compass, you are ensured consistent and up-to-date access to the latest API standards.  For additional information, please use the e-mail or visit API's Standards Subscription Service.

  • The subscription updates itself, so your subscription automatically reflects the latest edition.
  • 24/7 desktop access to critical information for all users at the licensed location.
  • Version comparison to quickly identify critical changes.
  • The ability to collaborate internally within the standard.

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Additional Information and Questions

The companion video, highlighting key changes and the implications for API Monogram licensees, will be available in early 2019.

To receive direct notification of when registration is open, please email with the subject “6A”.

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