Dimensional Stability and Shrinkage Under Heat
topic
Outer shell fabric dimensional stability under thermal exposure is assessed by measuring dimensional change after oven ageing at 260 degrees Celsius per ASTM F2894 and after flame exposure, with excessive shrinkage reducing garment coverage and exposing previously protected skin areas, while para-aramid fabrics exhibit excellent dimensional stability and meta-aramid fabrics show moderate shrinkage at temperatures approaching their thermal degradation range.
Role
Ensures that outer shell fabrics maintain adequate coverage of the body during thermal exposure conditions that cause some fibre types to shrink significantly, with dimensional stability being particularly critical at sleeve and trouser leg terminations where shrinkage would expose wrist and ankle areas previously covered by the garment, with EN 469 and NFPA 1971 specifying maximum allowable dimensional change after thermal conditioning.