Overview
EN ISO 20339:2017 - Non-destructive testing - Equipment for eddy current examination - Array probe characteristics and verification - specifies the functional characteristics of eddy current array probes and their interconnecting elements and provides methods for measurement and verification. The standard enables clear description and comparability of array probes and, where relevant, gives recommendations for acceptance criteria.
Key topics
The standard addresses measurement, verification and characterization of eddy current array probes, including:
- Probe types and application - definitions of surface and coaxial array probes and their intended use.
- Physical and environmental characteristics - mechanical properties, safety and operating conditions.
- Electrical characteristics - coil element impedance, impedance of patterns, channel assignment and sequencing.
- Functional characteristics - reference signal, normalization, lift-off effects, resolution, length of coverage and effective depth of detection.
- Signal integrity - measurement and limits for cross-talk and defective elements.
- Verification methods - levels of verification, required characteristics to be checked and methods for measurement.
- Surface probe specifics - reference blocks, probe motion, edge effects, response to slots and holes, variation in sensitivity between patterns, minimum slot length and probe clearance effects.
- Coaxial probe specifics - reference blocks, end and eccentricity effects, homogeneity of axial response, fill effect and effective penetration depth.
- Interconnecting elements - influence of cables and connectors on probe performance.
- Informative annexes - simulation guidance (e.g., for surface probe resolution).
These topics are defined and organized to allow reproducible measurements and acceptance testing of eddy current array probes.
Applications and who uses it
EN ISO 20339:2017 is used by:
- NDT engineers and inspectors validating eddy current inspection systems.
- Probe manufacturers and designers for characterization, quality control and product data sheets.
- Testing laboratories and certification bodies performing acceptance testing and intercomparison.
- Asset owners and maintenance teams in industries such as aerospace, power generation, rail, oil & gas and manufacturing where eddy current array testing is applied for surface and near-surface defect detection.
Practical benefits include improved comparability of probes, documented verification procedures, and clearer acceptance criteria for procurement and routine quality assurance.
Related standards
- Other ISO and EN standards on non-destructive testing (NDT) and eddy current inspection complement EN ISO 20339:2017. Users should consult the broader NDT standards suite and national implementation documents for conformity and application guidance.
Keywords: EN ISO 20339:2017, eddy current array probes, non-destructive testing, NDT, probe verification, array probe characteristics, reference blocks, lift-off, cross-talk, impedance measurement.