How do you test waterproof rating (mm) and breathability (g/m²/24h) for jackets?

Q: How do you test waterproof rating (mm) and breathability (g/m²/24h) for jackets?

Waterproof rating: the ISO 811 hydrostatic head test presses water against the fabric until it penetrates; the result in millimetres of water column is the 'mm' rating (10,000 mm = 10 metres of water pressure). Higher is better. Breathability: measured as moisture vapour transmission in g/m²/24h using JIS L 1099 B-1 (inverted cup, the most common factory spec), ASTM E96, or as Ret (resistance to evaporation) under ISO 11092. Never compare numbers across different test methods — a 20,000 g/m²/24h JIS result and an ASTM E96 result are not equivalent. Ask your factory which method each figure uses and request per-batch reports.

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Accepted Answer

Waterproof rating: the ISO 811 hydrostatic head test presses water against the fabric until it penetrates; the result in millimetres of water column is the 'mm' rating (10,000 mm = 10 metres of water pressure). Higher is better.

Breathability: measured as moisture vapour transmission in g/m²/24h using JIS L 1099 B-1 (inverted cup, the most common factory spec), ASTM E96, or as Ret (resistance to evaporation) under ISO 11092. Never compare numbers across different test methods — a 20,000 g/m²/24h JIS result and an ASTM E96 result are not equivalent. Ask your factory which method each figure uses and request per-batch reports.