Overview
EN ISO 12572:2016 - titled Hygrothermal performance of building materials and products - Determination of water vapour transmission properties - Cup method (ISO 12572:2016) - defines an isothermal cup-test method for measuring water vapour transmission. The standard specifies procedures to determine water vapour permeance of products and water vapour permeability of materials under controlled temperature and relative humidity. It is applicable to hygroscopic and non-hygroscopic building materials, including insulation materials, facing layers and integral skins. Results are intended for design, production control and inclusion in product specifications.
Key topics and technical requirements
- Test principle: cup method under isothermal conditions to measure mass change due to vapour flow.
- Apparatus and setup: requirements for test chambers, humidity control, and cup assemblies.
- Specimen preparation: dimensions, thickness, number of specimens and conditioning regimes (including provisions for insulation and core materials).
- Test conditions: defined temperature and relative humidity environments with specified test permutations.
- Calculations and output: mass change rate, vapour flow density, water vapour permeance, water vapour resistance, water vapour permeability, vapour resistance factor and equivalent air layer thickness.
- Accuracy and uncertainty: guidance on specimen area, thickness, weighing precision, sealing, environmental control and effects of barometric pressure.
- Reporting: required information to include in test reports for traceability and specification use.
- Normative annexes: dedicated methods or corrections for specific material types and test situations (self-supporting materials, loose fills, membranes/foils, mastics/sealants, paints/varnishes, edge corrections, air-layer resistance, etc.). Informative annexes cover weighing repeatability and unit conversions.
Applications
- Determining water vapour transmission properties for building material selection and hygrothermal design.
- Verifying product performance for manufacturers (quality control and production testing).
- Generating data for specifications, performance declarations and compliance documentation.
- Supporting building-physics assessments (moisture transport, condensation risk, hygrothermal modelling).
Who uses this standard
- Test laboratories and certification bodies performing vapour transmission tests.
- Manufacturers of insulation, membranes, coatings, sealants and other building products.
- Building physicists, façade and envelope designers, specifiers and regulatory authorities.
Related standards / context
- This European adoption (EN ISO 12572:2016) was prepared by CEN/TC 89 in collaboration with ISO/TC 163 and supersedes EN ISO 12572:2001. Use alongside national regulations and complementary hygrothermal standards for comprehensive moisture performance assessment.
Keywords: EN ISO 12572:2016, ISO 12572:2016, cup method, water vapour transmission, vapour permeance, vapour permeability, hygrothermal performance, building materials.
