API 5CT 11th Edition: What Does It Mean for OCTG Thread Protectors?


MAxX thread protectors, designed to meet API standards with liftable and non-liftable options, ensuring comprehensive protection for threaded components in the oil and gas sector.

The oil and gas industry operates under strict standards to ensure optimal performance and equipment safety. The recent release of the API 5CT 11th Edition in December of 2023 brought significant changes that impact OCTG thread protectors. With a focus on improving performance requirements, this edition has sparked discussions about its implications for API and non-API threaded products. In particular, the alteration in annex sections has raised questions about how thread protectors will need to adapt to adhere to the new standards. This blog delves into the key modifications introduced in the API 5CT 11th Edition and explores the implications for MSI’s OCTG thread protectors.

The API 5CT 11th Edition was released in December 2023, with an effective date of December 19, 2024. The annex that defines the performance requirement for thread protectors underwent a major change. While this spec only regulates performance for API and SF thread protectors, many customers wish to have the same performance requirements apply to their premium (non-API) threaded products as well.

The API 5CT 11th Edition Changes

The previous edition of the 5CT included protector requirements in Annex I. Annex I split casing and tubing into three size ranges (≤3 ½, 3 ½ – 8 ¾, ≥ 8 ¾), giving impact performance requirements for each size range. The current edition of the 5CT includes protector requirements in Annex F. Annex F splits the sizes into five ranges (2 3/8 – 4 ½, 4 ½ – 6 5/8, 6 5/8 – 8 5/8, 8 5/8 – 16, 16 – 20), giving both Class A and Class B impact requirements for each range.

In nearly every instance, the impact requirements for Annex F Class A are lower than the requirements for the same size pipe in Annex I. The requirements for Class B in Annex F are about half of the requirements for Class A. Because of the reduced required performance, the MSI product lines that were qualified for Annex I (Maxx, Ultra, and Mega) will all have more than enough impact resistance to meet the Annex F Class A criteria.

Magnum thread protectors are known for their robust design and high level of protection for heavy-duty threaded components in the oil and gas industry.

The MSI Maxx, Ultra, and Mega product lines will now perform well over Annex F Class A requirements and have a proven history of protection in rail and vessel transportation. As the Annex F impact values have reduced, we do not have evidence to say that protectors meeting only the Annex F Class A performance values will continue to be suitable for the more demanding rail and vessel transportation scenarios.

The other major change is a requirement that API and SF thread protectors have a marking that reflects 5CTA or 5CTB to indicate that they meet either the Class A or Class B requirements.

Stripping Tests (pin only): These are required for both Class A and Class B. The only change is a clarification in the procedure requiring the load to be applied uniformly around the protector, which MSI has always done by using rings to load the protector evenly around the base.

L4 length coverage: The requirement has not changed from the previous edition to the new edition. Both 10th Ed. 12.2.1 and 11th Ed. 11.2.2 states that external thread protectors shall cover the full length of the thread (L4 length), and internal thread protectors shall cover the equivalent total length of the internal thread. Our MaxX, Ultra, Mega, Magnum, and Titan API products all adhere to the L4 length requirements.

Titan thread protectors showcasing their sturdy construction and reliable thread protection for OCTG products.

MSI has the following product lines that meet the new API 5CT annex F standard:

API 5 CT Annex I, 10th ed. API 5CT Annex F, 11th ed Class A. Plus Rail and Vessel Transportation

API 5 CT Annex I, 10th ed. API 5CT Annex F, 11th ed Class A. Plus Rail and Vessel Transportation

API 5 CT Annex I, 10th ed. API 5CT Annex F, 11th ed Class A. Plus Rail and Vessel Transportation

API 5CT Annex F, 11th ed. Class A
API 5CT Annex F, 11th ed. Class B

API 5CT 11th Edition: MSI’s OCTG Thread Protectors Lead the Way in Meeting Updated Standards


The release of the API 5CT 11th Edition marks a significant milestone in the regulation of thread protectors within the oil and gas industry. The adjustments in Annex F impact performance requirements signal a shift towards more stringent criteria for Class A and Class B protectors. As MSI’s product lines, including Mega, Ultra, MaxX, Magnum, and Titan, align with the updated standards, customers can rest assured that these thread protectors surpass the mandated regulations.

Moving forward, manufacturers and suppliers must adapt to these changes to maintain compliance and ensure the protection and integrity of OCTG products throughout transportation and usage. By staying informed and proactive in implementing these new standards, industry players can confidently and efficiently navigate the evolving landscape of thread protector requirements.

MSI has the perfect pipe protection products for your needs.

Browse our online catalog, call, or email us for more information.

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