What the API Individual Certification Programs are

The American Petroleum Institute has run its Individual Certification Programs (ICP) since 1989. They test and certify the knowledge and experience of inspection and technical people in the oil, gas and petrochemical industries. Each certification is tied to one or more API codes or recommended practices, and each combines an eligibility check with an examination.

In outline, most of the inspector certifications work the same way. Candidates qualify through a combination of education and relevant experience, with more years of experience needed the less formal technical education they have. The examinations are based on a published body of knowledge and the referenced codes. Certifications are typically valid for three years, and recertification asks for evidence of continued work in the field and, periodically, a short test on code changes. Because the details change, check API's current program pages and body of knowledge before you apply; this article describes the programs as of September 2026.

The three core inspector certifications

  • API 510, Pressure Vessel Inspector. Covers in-service inspection, repair, alteration and rerating of pressure vessels under the API 510 Pressure Vessel Inspection Code. Held by inspectors who plan and approve vessel inspections, evaluate thickness data and corrosion rates, and approve repairs in refineries and chemical plants.
  • API 570, Piping Inspector. The same role for in-service process piping under the API 570 Piping Inspection Code: circuits, condition monitoring locations, inspection intervals, and repair and alteration of piping systems.
  • API 653, Aboveground Storage Tank Inspector. Covers inspection, repair, alteration and reconstruction of atmospheric steel storage tanks under API 653, including tank bottoms, shells and settlement. Held by inspectors at refineries, terminals and pipeline tank farms; federal rules require API 653 inspection of many pipeline breakout tanks.

The codes call for inspection to be performed or overseen by an authorized inspector, and the matching API certification is the usual evidence of that competence. Many owners require it in their inspection contracts.

API 1169, pipeline construction

API 1169, Pipeline Inspector, is based on API's recommended practice for basic inspection requirements on new onshore pipeline construction. It tests general knowledge of pipeline construction inspection, the inspector's duties, and the safety and environmental controls on a construction spread. It is aimed at the people who oversee construction for the pipeline owner, not at in-service integrity work.

The knowledge certifications: 571, 577 and 580

  • API 571, Corrosion and Materials, is based on API RP 571 and tests knowledge of the damage mechanisms that affect refinery and petrochemical equipment. It suits inspectors, corrosion specialists and engineers who set inspection strategies.
  • API 577, Welding Inspection and Metallurgy, is based on API RP 577 and covers welding processes, procedure and welder qualification, weld inspection and the metallurgy behind them, in the context of repair and fabrication for the petrochemical industry.
  • API 580, Risk Based Inspection, is based on API RP 580 and covers how RBI programs are set up and run.

These are often added on top of a 510, 570 or 653 certification. API 577, for example, accepts current 510, 570 and 653 holders as eligible.

API 936, refractory

API 936, Refractory Personnel, covers the installation, inspection, testing and repair of monolithic refractory linings to API Standard 936: material qualification, applicator testing, installation quality control and as-installed testing. It is for the people who oversee refractory work in heaters, reactors, regenerators and other lined equipment.

Other programs worth knowing

API also certifies tank entry supervisors (TES) and source inspectors for fixed, rotating and electrical equipment (SIFE, SIRE and SIEE), who inspect equipment at the manufacturer's shop before it ships. And it runs a family of hands-on ultrasonic examiner qualifications (QUTE and related programs for phased array, sizing and thickness measurement). These are performance demonstrations: candidates find and size flaws in real test specimens. API's pages state that candidates must already hold a UT Level II or higher from an employer-based or ISO 9712-type scheme, so these programs build on NDT certification rather than replacing it.

API inspectors and NDT technicians: who does what

An API certification is not an NDT certification, and an NDT certification is not an API inspector certification. The two roles are complementary:

  • NDT technicians, certified by their employers to schemes such as ASNT's SNT-TC-1A or CP-189, or centrally to ISO 9712, perform and interpret the examinations: the thickness readings, the phased array scans, the magnetic particle tests. They report what the equipment looks like.
  • API inspectors judge what it means against the inspection code: calculating corrosion rates and remaining life, setting the next inspection date, deciding when a fitness-for-service assessment or a repair is needed, and approving repairs.

In practice, a 510 or 570 inspector directs the NDT scope, and the quality of their decisions depends on the quality of the NDT data. Owners who want reliable programs need both roles qualified, and a clear handoff between them.

API 577 or 1169 versus an AWS CWI

The Certified Welding Inspector (CWI) program of the American Welding Society is the general welding-inspection credential across structural, fabrication and many other industries. API 577 covers similar ground from the refinery repair and fabrication angle and is written around API documents; it is often held alongside a 510 or 570. API 1169 covers the whole pipeline construction job, of which welding inspection is one part. Contracts decide which is required: a structural steel job may require a CWI, a refinery repair an API inspector with 577, and a pipeline spread an API 1169 inspector, sometimes with a CWI for the welding.

Frequently asked questions

What is the difference between API 510 and API 570?

API 510 certifies inspectors of pressure vessels under the API 510 code; API 570 certifies inspectors of process piping under the API 570 code. The skills overlap, corrosion rates, intervals and repairs, but the equipment, code rules and calculations differ, and many inspectors hold both.

API 510 or API 653: which do I need?

API 510 is for pressure vessels; API 653 is for atmospheric aboveground storage tanks. A refinery inspector often needs 510 and 570, while a terminal or tank farm inspector needs 653.

Is API 577 the same as a CWI?

No. Both cover welding inspection, but the AWS CWI is a general welding-inspector credential used across many industries, while API 577 is written around API documents for refinery and petrochemical repair and fabrication. Contracts specify which one they accept.

How do you become an API inspector?

Meet API's education and experience requirements for the program, apply, and pass the examination on the referenced codes. Experience requirements scale with education, and API sets out what kinds of work count. Check the current eligibility rules on API's program page before applying.

How often do API certifications need renewing?

API inspector certifications are typically valid for three years. Recertification generally requires evidence of continued work in the field, and some programs add a periodic online quiz on code changes. Check the current rules for your program.

Can an NDT Level II become an API inspector?

Yes, if they meet the program's eligibility requirements and pass the exam. Whether NDT work counts toward the required experience depends on the program's rules, so check with API. Holding both is common and useful.

How NDT LLC can help

NDT LLC helps owners and inspection companies connect the inspector and NDT sides of a mechanical integrity program: NDT procedures that match the API code and owner specifications, written practices and technician qualification, independent review of inspection data, and audit readiness. Contact us to talk it through. See also our articles on refineries and midstream pipelines.

This article is general information for a business audience, not engineering, legal or regulatory advice. Always work to the current edition of the codes, standards, regulations and manufacturer data that apply to your equipment and contracts.

NDT LLC is an independent consulting firm. It is not affiliated with, endorsed by or sponsored by the American Petroleum Institute (API), the American Welding Society (AWS), ASNT, ASME, OSHA, PHMSA, or any other organization named in this article; names are used only to identify the organizations and documents referred to.