ISO 17636: Non-Destructive Testing - Radiography of Welds
International standard for radiographic testing of welds covering procedures, equipment, and acceptance criteria. ISO 17636 is the international standard for weld radiography.
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 17636 is invoked when the scope of work matches its title — non-destructive testing - radiography of welds — and when the contract or regulatory regime cites it as the controlling document. On petroleum and petrochemical equipment, ISO 17636 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. 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
- Construction
- Manufacturing
- Oil & Gas
- Personnel qualification: examinations under ISO 17636 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.
- Image-quality verification: every radiograph or digital exposure carries a penetrameter / IQI of the type and thickness specified by the standard; the IQI must be visible and at the required sensitivity for the radiograph to be acceptable.
- Radiation safety: source handling, exclusion zones, dosimetry, and source recordkeeping must follow the licensing authority's rules in addition to the inspection standard itself.
- 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 17636 is invoked under a CE-mark or third-party certification scheme, conformity must be demonstrated through documented examination records reviewed by a notified body.
- Latest Edition
- ISO 17636-1:2022 (film) and ISO 17636-2:2022 (DDA/CR)
- First Published
- 2003
- Scope
- Radiographic testing of fusion welds — methods, IQI selection, exposure parameters, image quality classes A and B.
- Acceptance Criteria
- None — references ISO 5817 (acceptance for steel welds) and ISO 10675-1 (RT acceptance).
- Calibration / Qualification
- Personnel per ISO 9712; equipment per ISO 11699 (film) or ISO 17636-2 detector classes.
Key Clauses Inspectors Cite
- Sec. 6 — Source position and direction
- Sec. 7 — Image quality (with reference to ISO 19232)
- Sec. 8 — Examination procedures
- Annex B — Recommended techniques
Companion / Parent Standards
ISO 5817 (weld acceptance) · ISO 10675-1 (RT acceptance) · ISO 19232 (IQI) · ISO 11699-1 (film classification)
Sample Contract Language
“RT shall be performed per ISO 17636-1:2022 Class B technique; acceptance per ISO 10675-1 Level B.”
ISO standards are revised on a five-year systematic-review cycle. Updates to ISO 17636 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 17636 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 17636 cover?
ISO 17636 (Non-Destructive Testing - Radiography of Welds) is published by ISO. International standard for radiographic testing of welds covering procedures, equipment, and acceptance criteria.
Is ISO 17636 mandatory or voluntary?
ISO 17636 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 17636?
Inspections under ISO 17636 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 17636?
ISO 17636 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 17636
Organization
ISO
Methods Covered
1 method(s)
Industries
3 sector(s)
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