Water Vapour Transmission (MVTR) How It Changes with Construction and Elastane Content
Water Vapour Transmission (MVTR) 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 Water Vapour Transmission (MVTR) normally sit around higher means more breathable in mainstream production. Note ISO 15496 breathability 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 15496 breathability, so retest after any blending change. Record elastane content alongside Water Vapour Transmission (MVTR), because blends shift the measured value. A result outside higher means more breathable 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 Water Vapour Transmission (MVTR) lets suppliers quote without extra sampling rounds. Ask for conditioning details together with ISO 15496 breathability, since both affect the reading.
Typical range
Working values stay around higher means more breathable for mainstream activewear. Working figures for Water Vapour Transmission (MVTR) normally sit around higher means more breathable in mainstream production. Note ISO 15496 breathability on the tech pack so nobody tests against an older revision.
Development advice
Change one variable at a time, then verify against ISO 15496 breathability before moving to the next sample round. Record elastane content alongside Water Vapour Transmission (MVTR), because blends shift the measured value. A result outside higher means more breathable usually points to process drift rather than to the fibre itself.
