Washing Shrinkage and Relaxation Testing

Washing shrinkage testing (ISO 5077 with ISO 6330 domestic washing procedures) measures permanent dimensional change of fabrics and garments after standardised laundering cycles, providing the data for garment care label instructions and quality compliance with retail specification limits. ISO 6330 domestic washing procedures: Program 1A (40°C cotton cycle, top-loading, AATCC reference detergent, 63 L water, 12 min wash), 2A (40°C with phosphate), 4N (40°C non-phosphate, standard EU program), and tumble drying cycle A (low heat 60°C ± 5°C) or line dry — program selection determined by product care label and buyer specification. Specimen preparation: fabric cut 500×500 mm with 3 benchmarks in warp (50 mm from selvedge, 150 mm, 350 mm) and 3 in weft, measured pre and post test at standard atmosphere (20°C, 65% RH, 24 hour conditioning). Result calculation: % change = (after − before) / before × 100 (negative = shrinkage, positive = extension). Wool knitwear felting shrinkage (ISO 6330 5A/5B, 40°C wool program with gentle agitation, Superwash treated wool shrinkage <3% versus untreated wool 15–40% felting shrinkage — felting caused by ratchet effect of scale-covered wool fibres under wet agitation). Residual shrinkage measurement for sanforised cotton (Sanforizer mechanical pre-shrinking, target residual shrinkage ≤1.0% warp per ISO 5077 at 60°C wash) — Sanforize shrinkage below 1% required for US apparel market jeans and shirting.