Fabric samples are tested in the warp (lengthwise) and weft (crosswise) direction. They are clamped in a machine and extended until they break. The breaking load and extension are measured. The extensibility of the fabric contributes to its comfort.
Questions to consider:
Why is it an advantage to have natural stretch in the fabric?
Lorraine Greer (
Tensile strength testing is where we cut a certain number of pieces of fabric in a strip, because that’s the only way we can fit them in the machine, 50mm across and a particular length. We cut 5 warp and 5 weft samples. Warp samples are samples that we have cut with the length in the warp direction, which is the machine direction or the length of the fabric. The weft are the yarns that go across the fabric.
We put them on the machine, clamp them, pull them, extend them until they break. So not only do we get a figure for the breaking load, we also get a figure for extension – how much the fabric stretches before it breaks – and that is a very important part of comfort of fabrics, which is why people use elastomeric fibres. This fabric, of course, stretches naturally so you don't have to put elastomeric fibres in it.