Hydrostatic Head How It Changes with Construction and Elastane Content
Hydrostatic Head 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 Hydrostatic Head normally sit around 1000-10000 mm depending on use in mainstream production. Note ISO 811 water penetration 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 ISO 811 water penetration, so retest after any blending change. Record elastane content alongside Hydrostatic Head, because blends shift the measured value. A result outside 1000-10000 mm depending on use 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 Hydrostatic Head lets suppliers quote without extra sampling rounds. Ask for conditioning details together with ISO 811 water penetration, since both affect the reading.
Typical range
Working values stay around 1000-10000 mm depending on use for mainstream activewear. Working figures for Hydrostatic Head normally sit around 1000-10000 mm depending on use in mainstream production. Note ISO 811 water penetration on the tech pack so nobody tests against an older revision.
Development advice
Change one variable at a time, then verify against ISO 811 water penetration before moving to the next sample round. Record elastane content alongside Hydrostatic Head, because blends shift the measured value. A result outside 1000-10000 mm depending on use usually points to process drift rather than to the fibre itself.
