ISO 17638: Non-Destructive Testing - Weld Inspection Using Eddy Current Testing
International standard for eddy current testing of welds covering equipment, procedures, and acceptance criteria for detecting defects in welds.
The International Organization for Standardization (ISO) publishes the globally harmonised counterparts of regional NDT codes; ISO standards are the default outside the United States.
European, Middle Eastern, and Asia-Pacific procurement specifications routinely cite ISO standards directly; CE-marked equipment requires ISO compliance for entry into the EU market.
ISO 17638 is invoked when the scope of work matches its title — non-destructive testing - weld inspection using eddy current testing — and when the contract or regulatory regime cites it as the controlling document. On petroleum and petrochemical equipment, ISO 17638 usually feeds into a written mechanical-integrity program: inspection intervals, examination methods, and acceptance criteria are all traced back to a clause number in the document. Aerospace work treats the standard as a floor rather than a ceiling — most prime contractors layer their own internal procedures on top, with tighter acceptance criteria than the published code. In fabrication shops the standard is reproduced inside the written procedure book and referenced from every inspection report so that the auditor's paper trail leads back to the same paragraph the inspector worked from.
Methods covered
Industries
- Manufacturing
- Aerospace
- Oil & Gas
- Personnel qualification: examinations under ISO 17638 must be performed by inspectors qualified and certified to a recognised scheme (typically ASNT SNT-TC-1A, CP-189, or ISO 9712 depending on jurisdiction), with documented training hours, vision tests, and a controlling written practice.
- Written procedure: every examination requires a written, controlled procedure that names the method, equipment, calibration steps, scanning pattern, and acceptance criteria — and is qualified before first use.
- Eddy-current setup: probe selection, frequency, gain, and reference-standard calibration must be documented and verified against a reference standard with known artificial flaws prior to inspection.
- Acceptance criteria: indications are evaluated against the standard's tabulated limits (length, depth, alignment, frequency); any indication exceeding the criteria is recorded, dispositioned, and either repaired or evaluated for fitness-for-service.
- Documentation: examination reports must include enough information for a third party to reproduce the inspection — equipment serial numbers, calibration records, inspector ID, sketches of indications, and the controlling procedure revision.
- Conformity demonstration: where ISO 17638 is invoked under a CE-mark or third-party certification scheme, conformity must be demonstrated through documented examination records reviewed by a notified body.
ISO standards are revised on a five-year systematic-review cycle. Updates to ISO 17638 typically harmonise the document with parallel EN and ASTM publications, expand coverage of digital techniques, and clarify acceptance-criteria tables. EN-ISO dual-numbered standards reflect direct adoption by CEN; an EN-ISO citation is enforceable across the EU.
A typical refinery turnaround applies ISO 17638 to the inspection scope for high-temperature piping and pressure vessels: corrosion-monitoring locations are read with UT thickness gauges, girth welds on repaired sections are radiographed or PAUT-scanned, and any indication outside the standard's acceptance table is dispositioned through API 579 fitness-for-service before the unit restarts.
What does ISO 17638 cover?
ISO 17638 (Non-Destructive Testing - Weld Inspection Using Eddy Current Testing) is published by ISO. International standard for eddy current testing of welds covering equipment, procedures, and acceptance criteria for detecting defects in welds..
Is ISO 17638 mandatory or voluntary?
ISO 17638 is a consensus standard. It becomes mandatory when invoked by a contract, by another code that cites it (for example ASME Section V calling out an ASTM practice), or by a regulator that has adopted it into law in a specific jurisdiction.
Who is qualified to perform inspections under ISO 17638?
Inspections under ISO 17638 must be performed by personnel qualified and certified to a recognised NDT certification scheme — most commonly ASNT SNT-TC-1A or CP-189 in the United States, ISO 9712 in much of the rest of the world, and NAS 410 for aerospace work. The written practice that controls qualification must be in place before any examination is started.
Which other standards are commonly cited alongside ISO 17638?
ISO 17638 is most often cited together with the parent code that brings it into the contract — typically ASME Section V or VIII for U.S. pressure equipment, AWS D1.1 for structural welding, API 510/570/653 for in-service petroleum equipment, or the matching EN/ISO standard for European and international work.
Standard Code
ISO 17638
Organization
ISO
Methods Covered
1 method(s)
Industries
3 sector(s)
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