Acceptance sampling under ISO 2859-1 counts defects against acceptance numbers, usually with separate AQL levels for critical, major and minor defects. The standard gives the sampling plans; it does not decide which faults are major or minor. That is up to the buyer and should be written in the defect list. If broken stitches on a load-bearing seam are counted as minor, an order can pass with a fault that leads to returns.

How to classify

A common approach is to treat a defect as major if it is likely to make the garment fail in use or lead a customer to return it, and minor if it is a small departure from standard that is unlikely to do so. By that logic, an open seam, a hole or a run of broken stitches on a seam that takes strain is generally major. A single skipped stitch on a decorative topstitch, away from stress, may be minor.

Location matters

Write the classification by location. For hoodies, side seams, underarm points, pocket corners, cuff and hem joins take the most strain. For underwear, waistband joins, crotch seams and leg openings matter most. For tees, shoulder and neck seams. A fault in those areas should rank higher than the same fault elsewhere.

Look for patterns

Several pieces with broken stitches on the same seam suggest a machine, needle, thread or tension problem. The inspector should note the seam and ask the factory to check the line, even if the order passes.

Check seams under stress

Ask the inspector to stretch key seams gently by hand to see whether stitches crack. Washing a few pieces with a named procedure such as ISO 6330 can reveal weak seams that look fine when new.

Write it into the defect list

List each seam fault with its classification and location, and share the list with the factory before production. Ask for the defect classification to be used in the inspection report.

Review the defect list after each season, using returns and complaints to adjust what is treated as major.

If returns rise on one seam, raise its classification for the next orders and ask the factory for corrective action on that operation.