APEO and NPEO Limits How It Changes with Construction and Elastane Content
APEO and NPEO Limits does not stay constant when construction changes. Understanding the direction of change helps during development.
Effect of knit structure
Loop length and density move results first, usually before any yarn change is made. Working figures for APEO and NPEO Limits normally sit around usually below 100 ppm in mainstream production. Note extraction then LC-MS test on the tech pack so nobody tests against an older revision.
Effect of elastane content
More elastane raises recovery but changes the value measured by extraction then LC-MS test, so retest after any blending change. Record elastane content alongside APEO and NPEO Limits, because blends shift the measured value. A result outside usually below 100 ppm usually points to process drift rather than to the fibre itself.
Effect of finishing
Heat setting and softeners shift results, which explains differences between a hand sample and bulk. Keeping reference values for APEO and NPEO Limits lets suppliers quote without extra sampling rounds. Ask for conditioning details together with extraction then LC-MS test, since both affect the reading.
Typical range
Working values stay around usually below 100 ppm for mainstream activewear. Working figures for APEO and NPEO Limits normally sit around usually below 100 ppm in mainstream production. Note extraction then LC-MS test on the tech pack so nobody tests against an older revision.
Development advice
Change one variable at a time, then verify against extraction then LC-MS test before moving to the next sample round. Record elastane content alongside APEO and NPEO Limits, because blends shift the measured value. A result outside usually below 100 ppm usually points to process drift rather than to the fibre itself.
