Sewing strength tests determine the breaking strength or the highest resistance to breakage of the connection of one or more fabrics and stitches in the sewed fabrics.

While performing the tests, fabric samples which are taken from ready-to-wear woven fabric samples and which have pre-determined stitches or sewn with certain stitches are subjected to tests using various devices in order to determine the breaking strength and breaking strength of the stitches. For these tests, tools such as constant speed drawing device, sample elongation rate constant drawing device or loading rate constant drawing device are used.

For physical tests performed by accredited laboratories, many standards issued by local and foreign organizations are complied with. In this context, the standards which are taken as basis in the seam strength and seam flexibility tests are as follows:

• TS EN ISO 13935-1 Textile - Stitching properties of fabrics and finished textile articles - Part 1: Determination of the maximum force for seam break using the ribbon method
• TS EN ISO 13935-2 Textile - Stitching properties of fabrics and ready-made textile articles - Part 2: Determination of the maximum force for seam breaking using the clutch method
• TS EN ISO 13934-1 Textiles - Tensile properties of fabrics - Part 1: Determination of maximum force and length elongation under maximum force by strip method
• TS EN ISO 13934-2 Textile - Tensile properties of fabrics - Part 2: Determination of the greatest force using the coupling method
• ASTM D1683 Standard test method for failure of sewing of woven garment fabrics

Sewing efficiency of each fabric is different according to its properties. Therefore, to compare the stitch strength and stitch flexibility of different types of fabrics, one of the standard stitch groups specified in the relevant standard should be used.