Tolerances increase as the nominal size increases. For example: Over 30 to 120 mm: ±1 mm0;9f5; Over 400 to 1000 mm: ±2 mm
Some training centers and universities offer comparison tables between DIN 8570 B and ISO 5817 Level B. These are useful for reference but not for official compliance. din 8570 b pdf
For weld edge preparation, the relevant international standard is ("Welding and allied processes — Types of joint preparation"). Tolerances increase as the nominal size increases
Since DIN 8570 is a withdrawn standard, it is no longer sold by official publishers like DIN Media. However, here are the most realistic ways to access it or its modern equivalent: din 8570 b pdf