Textile Testing
Textile Testing covers sampling, conditioning, test methods, calculations and interpretation. The exam tests whether results are representative, comparable and correctly expressed in textile units.
Core concepts
- Sampling must represent the lot; random and systematic sampling reduce bias.
- Standard textile conditions are often 20 ± 2°C and 65 ± 4% RH; preconditioning matters for hygroscopic fibres.
- Tensile tests include strip, grab and ravelled strip methods; report breaking force, elongation and tenacity.
- Tear, burst, abrasion, pilling, colourfastness and dimensional stability each use distinct standards and specimen geometry.
- Colourfastness uses grey scales for change and staining; results are not interchangeable with strength tests.
- Results need mean, standard deviation, CV and uncertainty before comparison with specification.
Worked example
A 20 tex yarn breaks at 3.0 N. Tenacity = force/linear density = 3.0 N/20 tex = 0.15 N/tex = 15 cN/tex. If the test length is 500 mm and extension at break is 25 mm, strain = 25/500 × 100 = 5%. Report both tenacity and elongation: a strong but brittle yarn is not equivalent to a tough yarn.
Traps
- Testing without conditioning or after different relaxation.
- Confusing grab strength with strip strength.
- Using the wrong specimen width when converting to force per unit width.
- Reporting a single result without variability.