ISO 17697:2016 specifies two test methods for determining the seam strength of uppers, lining or insocks, irrespective of the material, in order to assess the suitability for the end use.
These methods are as follows.
- Method A: Needle perforations. For determining the force required to pull a row of needles through an upper material, in a direction perpendicular to the row.
- Method B: Stitched seams. For determining the breaking strength of stitched seams in shoe upper and lining materials. This method is applicable to seams cut from shoes or made up to simulate footwear constructions.