Overview
ISO 19285:2017 - "Non-destructive testing of welds - Phased array ultrasonic testing (PAUT) - Acceptance levels" defines acceptance levels for phased array ultrasonic testing (PAUT) of full‑penetration welds in ferritic steels with a minimum thickness of 6 mm. The standard aligns PAUT acceptance criteria with the quality levels of ISO 5817 and applies to indications classified according to ISO 13588.
Key topics and technical requirements
- Scope: PAUT acceptance levels for full‑penetration welds in ferritic steels (t ≥ 6 mm).
- Acceptance levels: Three levels (1–3) mapped to ISO 5817 quality:
- Level 3 - corresponds to ISO 5817 quality C/D (more restrictive)
- Level 2 - corresponds to ISO 5817 quality B
- Level 1 - by agreement (criteria are specified only for length/height evaluation)
- Evaluation methods:
- By length and height (Clauses 7 and 9)
- Or by length and maximum amplitude (Clauses 8 and 10)
- TOFD permitted for length/height measurement per ISO 15626
- Fixed amplitude level technique (Annex B) for length measurement
- Sizing rules:
- Length measured along the weld using the focal law that gives maximum amplitude (or TOFD)
- Height measured at the scan position of maximum extent; diffracted signals preferred (upper/lower tips) or alternative sizing (TCG, DGS, 6 dB drop, time‑of‑flight)
- Acceptance criteria:
- Tables define maximum allowable length and height by thickness ranges and acceptance level
- Cumulative length rules: for t ≤ 50 mm, sum of acceptable indications over 12t must not exceed specified limits (e.g., Level 1: 3.5t, max 150 mm; Level 2: 4.0t, max 200 mm; Level 3: 4.5t, max 225 mm). For t > 50 mm, limits are % of weld length with maximums (500–700 mm depending on level)
- Grouping rules: when separate indications are close in length and thickness direction they may be treated as one indication
- Normative references: ISO 5577, ISO 5817, ISO 11666, ISO 13588, ISO 15626, ISO 17640
Applications and typical users
ISO 19285:2017 is used by:
- NDT engineers and welding inspectors implementing PAUT
- Quality managers and fabricators in oil & gas, power generation, pressure vessel, and pipeline industries
- Organizations seeking objective acceptance criteria for PAUT in procurement specifications, inspection procedures, and conformity assessment
Practical benefits include standardized acceptance decisions, consistent defect sizing (length/height or amplitude), and clear cumulative/grouping rules for weld integrity assessment.
Related standards
Keywords: ISO 19285:2017, PAUT, phased array ultrasonic testing, acceptance levels, weld inspection, ferritic steels, ISO 5817, ISO 13588, TOFD, fixed amplitude level technique.
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