1. UNI EN 26520 (ISO 6520:1982) Classification of imperfections in metallic fusion welds.
2. ISO 5817:2014 Welding ‐ Fusion‐welded joints in steel nickel titanium and their alloys (beam welding excluded) ‐ Quality levels for imperfections.
3. ISO 10042:2018 Welding ‐‐ Arc‐welded joints in aluminium and its alloys ‐‐ Quality levels for imperfections.