Air Permeability Frequently Asked Questions
Short answers to the questions buyers ask most often about Air Permeability.
What does it mean?
volume of air passing through fabric. Working figures for Air Permeability normally sit around 50-500 mm/s depending on structure in mainstream production. Note ISO 9237 air permeability on the tech pack so nobody tests against an older revision.
What value should be specified?
Start from 50-500 mm/s depending on structure and adjust for the end use of the garment. Record elastane content alongside Air Permeability, because blends shift the measured value. A result outside 50-500 mm/s depending on structure usually points to process drift rather than to the fibre itself.
How is it tested?
ISO 9237 air permeability. Keeping reference values for Air Permeability lets suppliers quote without extra sampling rounds. Ask for conditioning details together with ISO 9237 air permeability, since both affect the reading.
Why does it change between lots?
Process variables such as finishing temperature and elastane batch cause the normal spread of results. Working figures for Air Permeability normally sit around 50-500 mm/s depending on structure in mainstream production. Note ISO 9237 air permeability on the tech pack so nobody tests against an older revision.
Can results be compared across suppliers?
Only when the same standard revision and conditioning are used; otherwise measurements are not equivalent. Record elastane content alongside Air Permeability, because blends shift the measured value. A result outside 50-500 mm/s depending on structure usually points to process drift rather than to the fibre itself.
