Ultrasonic Testing (UT) Requirements Under API 653

Sensitivity setting is the auditable step: the reference block used must itself be in calibration and traceable, and its identity recorded on the report. API 653, enforced by American Petroleum Institute is the certifying agency for the Authorized Inspector under.: Split, but differently from API 510 and 570.

An auditor examining UT asks for instrument, probes, cables, couplant, and the calibration and reference blocks used to set sensitivity. API 653 is the one code in this set that names an independent contract organization as an acceptable authorized inspection agency, so a tank inspection company can itself be the AIA for an owner-operator — a materially different commercial position from API 510 or 570. Three normative annexes carry most of the service-provider obligation: the Authorized Inspector Certification annex, which makes API the certifying agency for the inspector; the NDE Requirements Summary annex, which maps each method to where it is required, to its acceptance standard and to its examiner-qualification requirement; and, informatively, the annex on qualification of tank bottom examination procedures and personnel, which is where floor-scanning contracts are won and lost. The code recognises fitness-for-service assessment under API 579-1/ASME FFS-1 for degradation it does not itself address.

Source: API 653 Exam Administration Publications Effectivity Sheet for the March, July and November 2025 exams, api.org — verified for API Standard 653, 5th Edition, November 2014, with Addendum 1 (April 2018), Addendum 2 (May 2020) and Addendum 3 (November 2023), and for the referenced editions of API RP 571 (3rd, March 2020, listed mechanisms only), RP 575 (4th, July 2020), RP 576 (4th, April 2017, sections 4.3.2 and 6.6 only), RP 577 (3rd, October 2020), API Standard 650 (13th, March 2020 with Errata 1, January 2021), RP 651 (4th, September 2014), RP 652 (5th, May 2020), and ASME BPVC 2023 Edition Section V Articles 1, 2, 6, 7 and 23 (SE-797 only) plus Section IX, welding only. A fourth addendum has appeared in reseller listings; confirm against the current API effectivity sheet before relying on it. API publisher's preview of the 5th edition, api.org — verified for the scope statement, the API 579-1/ASME FFS-1 relationship, and the full contents including Section 6.10 NDE, Section 12 Examination and Testing, Annex B (normative) evaluation of tank bottom settlement, Annex D (normative) Authorized Inspector Certification, Annex F (normative) NDE Requirements Summary and Annex G (informative) Qualification of Tank Bottom Examination Procedures and Personnel. The definitions of authorized inspection agency, authorized inspector, repair organization and critical zone, the structure of Annex F, and the recertification and actively-engaged rules were verified against the 3rd edition (2003) full text published at law.resource.org — the most recent complete text in the public domain — and cross-checked against API's current ICP recertification policy; re-check the exact wording against the 5th edition with addenda. Commonly cited interval formulas (external at five years or RCA/4N; ultrasonic thickness at RCA/2N or fifteen years; internal capped at twenty years, thirty with a release prevention barrier) come from secondary summaries only and are not stated as verified. API ICP Schedules & Fees for fees and 2026 exam windows.

Ultrasonic Testing under API 653 — procedure, personnel and evidence
Item	What applies	Why it matters
Regime	API Standard 653, Tank Inspection, Repair, Alteration, and Reconstruction — Aboveground Storage Tank Inspection Programme	Enforced by American Petroleum Institute is the certifying agency for the Authorized Inspector under the code's normative Authorized Inspector Certification annex; the inspection programme is owned by the tank owner-operator and, where the state has adopted API 653, overseen by the state environmental or fire-safety authority
Method	Ultrasonic Testing (UT)	Needs its own procedure and its own qualified personnel
Procedure approval	The employer's Level III, qualified in this method	The signature an auditor traces
Other methods in scope	UT thickness, MFL floor scanning, Vacuum box testing, RT, MT, PT	Each needs separate qualification
Renewal	No company certificate. The API 653 Authorized Inspector certificate runs three years. Recertification requires the inspector to remain actively engaged — defined in the code's certification annex as a minimum of 20 percent of time spent performing or supervising API 653 inspection activities over the most recent three-year certification period — and inspectors who have not been actively engaged must recertify by written examination. Once every second recertification period, that is every six years, an actively engaged inspector must demonstrate knowledge of the revisions made in the previous six years; API currently satisfies this with a 25-question open-book web quiz. Published API fees are $875 member and $1,125 non-member initial, $745 and $855 recertification. The 2026 API 653 exam windows are 13 March–3 April and 10–31 July 2026.	Applies to the personnel certification behind this method

Does API 653 require a separate procedure for UT?

Yes. Every method in scope needs its own written procedure, approved by someone qualified in that method, describing technique, equipment, calibration, scanning or coverage, acceptance criteria and reporting. A single combined "NDT procedure" covering several methods is a finding under every regime that names procedures individually.

Who can approve a UT procedure under API 653?

A Level III qualified in UT. Because API 653 accepts employer-based certification, that Level III may be contracted rather than employed — but their own qualification must cover UT, and an auditor will check that before accepting the signature.

What UT records does a API 653 audit sample?

The approved procedure, the technician's UT certification on the date of work, and the equipment evidence — instrument, probes, cables, couplant, and the calibration and reference blocks used to set sensitivity. The auditor works backwards from a finished job, so every item has to reconcile with the report and its stated acceptance criteria.

What is the most common UT finding at audit?

An in-calibration instrument used with an unidentified or out-of-calibration reference block. It is a records failure rather than a technique failure — the examination was performed correctly and the evidence supporting it cannot be produced, which under API 653 is recorded the same way as not having done the work.

Can a technician certified elsewhere perform UT under API 653?

Not automatically. Employer-based certification ends when the holder leaves, so the new employer must certify them under its own written practice. Prior training and documented experience transfer as evidence; the certificate itself does not.

What equipment evidence does UT need under API 653?

Calibration status traceable to the day of use, covering the instrument and its accessories — probes, cables, blocks and reference standards for ultrasonics; sources and densitometers for radiography. An in-calibration instrument with an out-of-calibration reference block fails the same way as an uncalibrated one.

How do UT requirements differ from the other methods in API 653?

Scope, qualification and evidence are method-specific, so the differences are real rather than administrative. API 653 also covers UT thickness, MFL floor scanning, Vacuum box testing, RT, MT, and each carries its own procedure, its own personnel qualification and its own equipment evidence.

Personnel certification for UT

Split, but differently from API 510 and 570. The Authorized Inspector is centrally certified by API under the code's normative certification annex — API is the certifying agency, and the inspector must be an employee of an authorized inspection agency. Critically, that agency may be an independent organization or individual under contract to and under the direction of the owner-operator, recognised or not prohibited by the jurisdiction, provided the owner-operator's inspection programme provides the necessary controls. NDE examiner qualification is not routed through a single scheme: the normative NDE Requirements Summary annex sets the requirement method by method, and for several methods defers to API 650's requirement for an examiner with adequate vision who is competent in the examination, interpretation and evaluation of results. Employer-based certification governs, and an outsourced Level III can approve the procedures and certify the examiners.