Overview
EN ISO 15548-3:2008 (ISO 15548-3:2008) specifies the system characteristics and verification methods for general-purpose eddy current equipment used in non-destructive testing (NDT). The standard defines functional characteristics of an eddy current system (instrument, probes, interconnects, mechanical arrangements and accessories) and gives procedures for measuring and verifying these characteristics so that equipment description and performance are comparable and traceable. It does not set acceptance criteria or verification extents - those are defined in application-specific documents.
Key topics and requirements
- System scope: A system comprises the instrument, probe arrangement, cables/slip rings, mechanical fixtures, accessories and reference pieces.
- System characteristics: Grouped into
- Physical characteristics (throughput speed, scanning path, mechanical settings and interactions with the test piece),
- Calibration-related characteristics (response to reference blocks and correlation with inferred parameters such as coating thickness or crack depth),
- Functional characteristics (instrument/accessory settings, balance and origin of complex-plane display, dynamic range in amplitude and phase).
- Accessories: Lift-off compensation, marking, magnetic saturation, demagnetizing, data acquisition/analysis - must be characterized and verified when they influence results.
- Verification levels: Three-tiered verification strategy:
- Level 1 - Global functional check: frequent, on-site checks using reference blocks (e.g., hourly/daily) to confirm stability.
- Level 2 - Detailed functional check and calibration: less frequent (typically annual or after repair) using calibrated instruments and reference blocks.
- Level 3 - Characterization: comprehensive verification (e.g., on release) against manufacturer specifications using laboratory-calibrated measuring equipment.
- Verification procedure & corrective actions: Procedures must specify characteristics, periodicity, trigger events (e.g., component replacement), measurement methods, acceptable limits and corrective steps (recalibration, extended verification, re-examination of products since last successful check).
Applications and users
- Practical uses: Designing and commissioning eddy current inspection systems, establishing verification programs, ensuring equipment comparability, and documenting system performance for quality assurance and regulatory compliance.
- Typical users: NDT engineers, inspection specialists, quality managers, equipment manufacturers, calibration laboratories and organizations developing application-specific NDT procedures.
- Sectors: Aerospace, power generation, oil & gas, rail, automotive and any industry using eddy current methods for surface and near-surface defect detection, coating/thickness assessment or conductivity evaluation.
Related standards
- ISO 15548-1: Instrument characteristics and verification
- ISO 15548-2: Probe characteristics and verification
- ISO 12718: Eddy current testing - Terminology
- ISO 15549: Eddy current testing - General principles
This standard enables consistent, verifiable eddy current NDT by defining what to measure and how to verify system performance, while leaving application-specific acceptance criteria to dedicated documents.
