Which test is crucial for determining fabric stretchability?

The correct choice is significant because ISO 13934 is specifically designed to assess the stretching and breaking strength of fabrics. This test measures the tensile properties of textiles, which include how much a fabric can stretch before it reaches its breaking point. Understanding the stretchability of a fabric is essential, especially in applications where comfort and fit are important, such as in activewear or fitted clothing.

Other tests mentioned, while relevant to various fabric properties, do not focus primarily on stretchability. ASTM D5034 evaluates the tearing strength of fabrics, AATCC Test Method 135 assesses the fabric's resistance to snagging, and ASTM D1234 covers various aspects but does not specifically address stretchability. Therefore, ISO 13934 stands out for its direct relevance to understanding and quantifying the stretch characteristics of fabrics.