Overview
EN ISO 9346:2007 - titled Hygrothermal performance of buildings and building materials - Physical quantities for mass transfer - Vocabulary - is a CEN-adopted International Standard that defines the vocabulary, physical quantities, symbols and units used for mass transfer (water vapour and related transport) in buildings, building elements and materials. It provides a harmonized set of terms and notation to support consistent measurement, calculation, reporting and communication in hygrothermal design, testing and simulation.
Key topics
- Standard scope: vocabulary and definitions for mass transfer relevant to buildings, building components and building materials.
- Physical quantities: authoritative list of quantities used in mass transfer analysis together with the corresponding symbols and units.
- Terms and definitions: harmonized definitions including revised terminology where “moisture” has been updated to “water vapour” in several terms.
- Notation rules: recommended subscripts and symbol conventions to ensure consistency across calculations, reports and software.
- Editorial updates: this 2007 edition supersedes earlier editions and incorporates amendments (addition of new terms and completion of the subscripts list). It also aligns the symbol for relative humidity with related standards (changed from φ to ϕ).
Applications
EN ISO 9346:2007 is primarily a vocabulary and notation standard but provides practical value across disciplines that address hygrothermal behavior:
- Building designers and architects - for consistent specification of hygrothermal parameters in design documents.
- HVAC and building-physics engineers - to ensure uniform use of symbols and quantities in calculations and simulations (moisture/water vapour transport, condensation risk assessments).
- Materials and façade manufacturers - to describe sorption, permeability and other mass-transfer related properties in product data sheets and test reports.
- Test laboratories and certification bodies - to standardize reporting and interpretation of mass-transfer test results.
- Software developers and researchers - to implement consistent variable names, units and indices in hygrothermal models and academic publications.
Related standards
- ISO 12572 and ISO 13788 (noted in EN ISO 9346:2007 for harmonization of relative humidity symbol)
- Other hygrothermal and building-physics standards and national regulations that reference consistent terminology and units for moisture and mass transfer.
EN ISO 9346:2007 is a foundational vocabulary reference for anyone working with hygrothermal performance, facilitating clearer communication, consistent data exchange and reliable hygrothermal analysis across design, testing and research.
