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API Specification 5CT, 10th Edition

We are pleased to announce the publications of the 10th edition of Specification 5CT, Casing and Tubing, and the 7th edition of Technical Report 5C3, Calculating Performance Properties of Pipe Used as Casing or Tubing. These new editions provide technical updates that have reached consensus within API’s Subcommittee on Tubular Goods and will now give industry consistent practices in the respective areas of the standards. As part of API’s standards develop program, 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.

The key changes to highlight for Spec 5CT are:

  • Scope to reference RP 5C6 for new requirements for large diameter PSL 2 casing not specifically covered by Spec 5CT (e.g. conductor casing)
  • New content on converting USC unit to SI units to be used in stress intensity factor toughness and updates to SSC requirements
  • Updated pipe range length requirements for carload shipping
  • Update requirements for grade N80 Type 1
  • Update requirements for pipe with special end-finish threads
  • Updates to how material grades are grouped throughout document
  • Eliminate Supplementary Requirement 15 (test certificates) and add new requirements for mill test reports/certifications in its place
  • Expand triangle stamp marking requirements
  • Add polymer quenching for grade L80
  • Update hardness requirement for grades L80, C90, T95 and C110 as result of NACE MR0175
  • Delete clause on reducing couplings
  • Update requirements for L80 13Cr inside surface preparation
  • Expand requirements for NDE personnel certification
  • Elimination of grade M65 entirely from the specification
  • Updates and clarifications for NACE testing methods as result of updates to NACE’s requirements
  • Increase casing coupling OD wall thicknesses for 4-1/2, 5 and 5-1/2 inch, and update spec respectively throughout as result, e.g. recalculate weight gain/loss of material
  • The key changes to highlight for TR 5C3 are:
  • Increase casing coupling OD wall thicknesses for 4-1/2, 5 and 5-1/2 inch, and update TR respectively throughout as result
  • Updates to using nominal linear mass in calculations and remove equation for calculating theoretical mass
  • Corrective updates to mass steel density and related equations and calculations

Effective Date and Program Implications

The Monogram Program effective date will be July 1, 2019.

Current licensees shall ensure that products manufactured on and after July 1st, 2019 meet the requirements of API 5CT 10th edition in order to be monogrammed.

Also, effective July 1st, 2019, API 5CT audits will be conducted to the 10th edition of the document.

To Purchase

Specification 5CT and Technical Report 5C3 are 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 visit API's Standard 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

Purchase the standard at the API webstore.

Additional Information and Questions

A companion video, highlighting key changes and the implications for Monogram licensees, will be available for viewing in August. Registration details will be available mid-May. To receive direct notification of when registration is open, please email with the subject “5CT”.

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