Table of Content
- Introduction
- Eddy Current Testing Standards: Why Eddy Current Testing Standards are important
- The Four Categories of Eddy Current Standards
- ASTM Standards for Eddy Current Testing
- ASME Requirements: Section V, Article 8
- ISO and EN Standards
- Calibration and Reference Standards
- What a Compliant Eddy Current Procedure Must Contain
- Guidance on How to Determine Which Standard Will Be Used for Your Inspection
- Conclusion
- FAQ
Introduction
Eddy current testing (ECT) is used to inspect surface and near surface discontinuities, tubes and bars, to measure coating thickness, to determine electrical conductivity and to evaluate conductive material. Accurate inspection is dependent on the correct application of the eddy current testing standards, however.
Governed inspection requirements may be identified in a purchase order, construction code, material specification or client requirement. That document may refer to an NDT method standard which serves as the basis for a written inspection procedure.
This guide outlines the key requirements of the major ASTM, ASME, ISO and EN specifications for eddy current testing and how to determine which of those specifications is applicable to a specific inspection.
This same standards-governance logic applies across NDT methods, see our foundational guide to NDT as a discipline.
→ Read: What Is NDT? (Non-Destructive Testing)
Eddy Current Testing Standards: Why Eddy Current Testing Standards are important
Typically, an eddy current inspection process is carried out in a specific technical sequence:
Contract / purchase order → Construction / product code → NDT method standard → Written inspection procedure
The method of examination, necessary equipment and standards of reference, and means of recording and evaluating the results are dependent upon the applicable standard.
The appropriate standard also depends on the product. Although the principle of the eddy current is the same, the standards are not necessarily identical for tubes, bars, wire, coatings, heat-exchanger tubing, and conductive materials.
This same standards-governance chain applies across NDT methods, ultrasonic testing follows a comparable structure.
→ Read: Ultrasonic Testing Standards and Codes
The four categories of Eddy Current Standards
Eddy current standards can be categorized into four practical categories.
Method and technique standards
They provide the details of the manner in which the eddy current examination is carried out: examination techniques, equipment set-up, calibration concepts, and other technical aspects. This is the category of ASME Section V Article 8, various ASTM practices.
Practice and application standards
These are used to examine a specific product or application, for example, tubings, bars, wire rope, coating thickness or conductivity.
Personnel qualification standards
These set criteria for NDT personnel qualification and certification. For example, ISO 9712 deals with the qualification of personnel in industrial NDT, including eddy current testing. It does not specify the entire inspection process.
The inspection method may not be a personnel qualification standard.
Equipment characterisation standards
These focus on the characteristics and verification of instruments and probes. Of particular note is ISO 15548, which deals with eddy current general-purpose instruments and probes.
Separating these categories makes it easier to avoid mistakes in inspection procedures.Personnel qualification standards are covered in more depth in our dedicated training path.
→ Read: Eddy Current Testing Course
ASTM Standards for Eddy Current Testing
Under the umbrella of ASTM's NDT standards, a large number of standards for electromagnetic examination are being published. Depending on the material, product form and the purpose of the inspection, the applicable document may be different.
The standards illustrate why there are no single ASTM standards for eddy current testing.
For instance, ASTM E1004 is devoted to electrical conductivity and ASTM E376 to coating thickness. Standards for tubular products vary depending on material and type of product.
Thus, the ASTM document should not be chosen because an eddy current instrument is being used but should be chosen based on the inspection application.
ASME Requirements: Section V, Article 8
When invoked by the applicable referencing code or specification, the requirements for performing eddy current examination are provided in ASME BPVC Section V, Article 8.
Article 8 covers aspects including examination procedures, equipment, techniques, calibration, examination, evaluation and documentation. Specialty applications, like heat-exchanger tubing, are also covered by ASME Section V.
Acceptance criteria are not automatically in Article 8
This separation is crucial:
The acceptance criteria are not to be found in Article 8, but rather in the references code.
An eddy current examination may be required by a construction or piping code and may have its acceptance/rejection criteria specified in that code in addition to this Code.
Thus, Article 8 examination alone does not establish the compliance of a component to a construction code.
Article 21 for Pulsed eddy current
Article 21, Pulsed Eddy Current (PEC) Technique for Corrosion Screening is also part of ASME Section V. It should therefore be considered as a specific technique, with specific requirements to which it is applicable, and not just assumed to meet all the requirements that could be inferred from those designed for a conventional eddy current examination.
Article 8 sits within a much larger code, see the full structure of ASME Section V for context on where eddy current examination fits.
→ Read: ASME Section V Overview
ISO and EN Standards
ISO has several complementary standards related to eddy current principles, terms, equipment and personnel.
ISO 15548 — Equipment characteristics
The ISO 15548 series deals with the characteristics and verification of eddy current equipment.
The ISO 15548-1:2026 lays down the general purpose eddy current instrument characteristics and their verification, and ISO 15548-2 covers the characteristics of probes and their verification.
These are equipment standards, NOT universal product inspection standards.
ISO 15549 — General principles
This ISO document outlines general principles for eddy current examination of products and materials and serves as a basis for application documents.
ISO 12718 — Vocabulary
The ISO 12718:2019 gives the terminology used in eddy current testing. This is helpful when you have inspectors, manufacturers and standards from different systems that have different technical terms.
ISO 9712 — Personnel qualification
ISO 9712:2021 provides the qualification and certification needs for industrial NDT personnel including eddy current testing. It is not to be confused with an examination method standard.
EN product standards
Similar eddy current specifications are also found in European tube and product specifications. The series EN 10246 has historically included electromagnetic testing of steel products and some of the provisions were later replaced by EN ISO standards.
For instance automatic eddy current testing of steel tubes (EN 10246-3) was replaced by EN ISO 10893-2.
ASTM vs ISO terminology
ASTM and ISO may use different terms or use different structures to document similar technical concepts. The definitions and terminology in the specific standard and edition, therefore, should be examined by the inspector conducting the work on the international project, and not assumed to have the same meaning as other terms with similar names.
Calibration and Reference Standards
The term “standard” used in eddy current testing can also refer to a physical reference specimen, and not a published technical document.
A known response that can be used to check an inspection system is produced by an eddy current calibration or reference standard. It can be a notched tube, a machined specimen, a conductivity block, a coating thickness reference or other specified object.
For instance, ASTM E215 specifies the reference standards that should have artificial discontinuities in order to standardise the equipment for the examination of seamless aluminium alloy tubes. The reference standards with known electrical conductivity are used for ASTM E1004.
The general principle is, calibration must conform to the inspection standard that governs it. However, a generic reference block should not automatically be used because it provides a good signal.
Browse our full range of eddy current probes and calibration reference standards to match your procedure's requirements.
→ Read: Eddy Current Probes & Reference Standards
What a Compliant Eddy Current Procedure Must Contain
Generally, a written eddy current procedure will cover the following:
- Scope: Components, material and dimensions as well as inspection objective.
- Applicable documents: Construction code, product specification and NDT method standard.
- Personnel: Necessary qualification or qualification that must be gained.
- Equipment: Instrument, probes, coils, cables, software and accessories.
- Technique: Probe arrangement, frequency, sensitivity, scanning pattern, speed and coverage.
- Calibration: Reference standard and required calibrations.
- Examination: Surface condition, accessibility, scanning and coverage.
- Evaluation: Process for assessing relevant and non-relevant indications.
- Acceptance criteria: Construction code, product specification or client requirement.
- Recording: Signalling, instrument setting, indication locations and traceability.
- Reporting: Results of inspection, equipment, personnel, standard used, and acceptance requirements.
This is the typical form of a controlled ECT treatment. It is not a quotation or complete checklist from any one ASTM, ASME or ISO standard.
Guidance on how to determine which standard will be used for your inspection
When the selection of the standard has a logical sequence, it is easier to choose the correct one.
Step 1: Determine the component.
Identify if it is a tube, pipe, bar, wire, heat-exchanger tube, coating, weld or other item. Differentiate between ferromagnetic and non-ferromagnetic materials also.
Step 2: Determine the governing specification.
Identify which document governs the work – is it from ASME construction code, ASTM material specification, an EN/ISO product standard, a client specification or a purchase order?
Step 3: Identify the invoked ECT method
The governing document may then refer to the appropriate eddy current method or product standard.
The basic chain is:
The most reliable, well-known way to do this is to follow the order of the boxes: Component → Governing code/specification → ECT method standard → Inspection procedure.
Step 4: Set staff needs
Identify the appropriate personnel qualification system, e.g. ISO 9712 or a code/certification system chosen by the employer.
Step 5: Confirm equipment requirements and calibration needs
Verify the requirements for the instrument, probe, calibration setup, reference specimen, artificial discontinuities, and the verification checks.
Step 6: Make sure that the edition is confirmed
When in doubt, always check the exact edition that is mentioned in the contract or purchase order.
A new version is not necessarily the current version of an existing project. In the absence of any changes specified in the contract, this is the edition specified there, unless the parties concerned agree otherwise.
It is the contract edition, rather than the current one, that applies.
For the full method breakdown behind this selection process, see our complete eddy current testing pillar guide.
→ Read: Eddy Current Testing: A Complete Guide
Conclusion
It's not enough to know a list of ASTM numbers or ASME Article 8 to understand eddy current testing standards. Standards have a variety of levels.
ASTM gives the requirements for the product and the application. When called for in a referencing code, ASME Section V Article 8 is an important framework for eddy current examination. There are general principles, terminology, equipment-characterisation needs, and personnel qualification requirements provided by ISO, and product standards (EN/ISO) cover specific European applications.
The most safe approach to make sure that the need is appropriate is to begin with the component and governing contract or code, then locate the called ECT method standard, determine personnel and equipment requirements, and check the actual version of the contract.
This way, the inspection process, calibration standard, human resources qualifications and acceptance criteria are in line with the real project needs.
FAQ
Which is the primary ASTM Standard for eddy current?
No single ASTM standard applies to all applications of ECT. Various standards cover tubes, heat-exchanger tubing, conductivity, coating thickness, bars, wire rope and other uses.
What does ASME Section V Article 8 say?
It is an article from the ASME Section V, and outlines the requirements of ECT when invoked by the applicable referencing code or specification.
Are there any acceptance criteria in Article 8?
Not as universal sets of limits. Acceptance criteria are derived from the referencing construction code, product specification or governing requirement.
What is ISO 15548 used for?
ISO 15548 covers characteristics and verifications of equipment used in eddy current examination such as equipment and probes.
What is ISO 15549?
ISO 15549 lays out the general principles for eddy current examination of products and materials.
Is ISO 9712 an eddy current method standard?
No. ISO 9712 is a standard for personnel qualification and certification. It is not a substitute for the relevant ECT examination standard.
What is eddy current calibration standard?
It is a specimen of physical material for the purpose of standardizing or checking an ECT system. It should be designed and used in accordance with the governing inspection standard.
What is the right ECT standard to choose?
Find the component and material, find the governing code or specification, find the method standard that governs the ECT, check the staff and calibration requirements, and get the required contractual edition.
