Overview
EN ISO 15496:2018 - Textiles: Measurement of water vapour permeability for quality control describes a comparatively simple, internationally recognized laboratory method for measuring the water vapour permeability of textile materials for in‑plant quality control. The method uses a water‑bath/dessicant‑cup arrangement with hydrophobic microporous membranes and a saturated potassium acetate solution (≈23 % RH) to quantify vapour transfer. EN ISO 15496:2018 clarifies limitations: it is not intended for physiological classification (e.g., comfort indices) or for evaluating personal protective equipment (PPE), and results do not correlate with other “dry desiccant” cup methods (see Annex C).
Key Topics and Requirements
- Scope & limitations: Designed for manufacturing quality control; not suitable for physiological performance classification or PPE standards; limited comparability with ISO 11092.
- Test principle: Specimen mounted with a waterproof, vapour‑permeable membrane; membrane contacts water in a controlled bath while a cup with saturated potassium acetate (≈23 % RH) is placed above. Net vapour transfer is measured by cup mass change.
- Apparatus essentials:
- Hydrophobic microporous membrane (two layers > 1.2 g/m²·Pa·h when tested per this method)
- Specimen holder (ring with groove and clamping rubber)
- Support frame with numbered holes and immersion depth control (immersed to (5 ± 2) mm)
- Water bath maintained at (23.0 ± 0.1) °C, with temperature monitoring at multiple positions
- Procedure details: Specimen and membrane equilibration, timed weighing of the cup before and after exposure (typical 15 min periods noted), and parallel apparatus control test to correct for membrane permeability.
- Calculation & precision: Results expressed as water vapour permeability (μWV) with corrections for apparatus permeability; document includes information on repeatability and reproducibility.
- Informative annexes: Annex A (applicability/classification), Annex B (physical principles), Annex C (comparison/explanation of dry desiccant cup methods).
Applications
- Primary use: On‑line or in‑plant quality control by textile manufacturers to monitor batch consistency of water vapour permeability.
- Who uses it:
- QC managers and laboratory technicians in textile production
- Textile testing laboratories performing routine acceptance tests
- R&D teams assessing finishing processes that affect breathability
- Practical value: Fast, reproducible screening test for production control; helps detect process drift, coating/finish defects, or fabrication issues that alter vapour transfer.
Related Standards
- ISO 11092 - referenced as a more comprehensive method for evaluating water vapour resistance (physiological relevance and comfort indices).
- Other dry desiccant cup methods - EN ISO 15496:2018 warns results will not correlate; see Annex C for explanation.
Keywords: EN ISO 15496:2018, water vapour permeability, textiles, quality control, breathability test, desiccant cup, ISO 11092, textile testing.