# ISO 5817 Quality levels for imperfections in welds

> ISO 5817, Welding - Fusion-welded joints in steel, nickel, titanium and their alloys (beam welding excluded) - Quality levels for imperfections, defines three quality levels, B (stringent), C (intermediate) and D (moderate), with limits for each type of imperfection.

- Source: https://amps.global/glossary/iso-5817/
- Type: Glossary
- Published: 2026-09-05
- Tags: standards

## Key facts

- Level B is the most demanding; the level is chosen by the design specification, not by the inspector
- Used directly for visual testing and, through ISO 17635, mapped to NDT acceptance levels in ISO 10675 (RT), ISO 11666 (UT), ISO 23277 (PT) and ISO 23278 (MT)
- Aluminium has its own standard, ISO 10042
- Common in European-designed equipment and in wind energy and rail projects

Also known as: EN ISO 5817, quality levels B, C, D.

## How it is applied

The drawing or specification states the quality level. The inspector measures each imperfection (undercut, porosity, excess weld metal, misalignment) and compares it with the limit for that level and thickness.

## In AMPS

Because AMPS generates reports from your own Word templates, the code clause, acceptance criteria and revision block stay exactly as your QA system wrote them, with job data filled in automatically.

## Related pages

- [ISO 10675](https://amps.global/glossary/iso-10675/)
- [EN ISO 17635 series](https://amps.global/glossary/en-iso-17635-series/)
- [Acceptance criteria](https://amps.global/glossary/acceptance-criteria/)

## Sources

- [ISO - International Organization for Standardization](https://www.iso.org/)