WASHINGTON, October 7, 2026 — The American Petroleum Institute (API) today announced the publication of the 17th edition of API Specification 5B (API Spec 5B), Threading, Gauging, and Inspection of Casing, Tubing, and Line Pipe Threads. The new edition updates requirements for manufacturing, measuring and inspecting threaded pipe connections and includes new provisions for validating advanced measurement technologies.
Threaded connections join the line pipe, casing, and tubing, that enable wells to operate and energy products to move throughout the supply chain. Because these connections must fit together precisely and perform reliably under high loads and demanding operating conditions, maintaining thread integrity is critical to the performance of wells and piping systems. Reliable connections also help reduce the risk of leaks and failures.
API Spec 5B helps maintain thread integrity by establishing consistent requirements for these threaded connections. First published in 1939, the specification establishes a common basis for manufacturers, inspectors, and purchasers, to confirm that connections meet specified dimensions and acceptance criteria. Those requirements support interchangeability across manufacturers and give users confidence in consistent connection performance.
“Reliable threaded connections depend on precision at the point of manufacture and confidence in how they are measured afterward,” API Senior Vice President of Global Industry Services Anchal Liddar said. “The 17th edition of API Spec 5B updates the standard for newer measurement technologies and increasingly demanding operating conditions.”
Developed through API’s open, consensus-based standards development process, the 17th edition builds on the 16th edition, published in 2017, and is intended to make inspection requirements easier to apply consistently. While the 16th edition focused on established dimensional conformity, inspection procedures and traditional gauging practices, the new edition expands that framework to recognize emerging measurement technologies and address the greater performance demands placed on Oil Country Tubular Goods (OCTG).
Key updates to API Spec 5B include:
The publication also reflects an expanded role for API Spec 5B within the API Monogram Program. Today, the standard serves as the primary Monogram specification for casing, tubing and line pipe threading activities, with more than 550 API Monogram licensees.
The new edition is complemented by the publication of the sixth edition of API Recommended Practice 5B1, Gauging and Inspection of Casing, Tubing and Line Pipe Threads. API RP 5B1 provides technical guidance and inspection practices to support application of API Spec 5B requirements.
The 17th edition of API Spec 5B is available through the API Webstore: apiwebstore.org.
The American Petroleum Institute (API) represents all segments of America’s oil and natural gas industry, supporting nearly 11 million U.S. jobs. With approximately 600 members, API companies produce, process, and distribute the majority of the nation’s energy. Founded in 1919, API has developed over 800 standards to enhance operational and environmental safety, efficiency, and sustainability.
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