Overview
EN ISO 10456:2007 - "Building materials and products - Hygrothermal properties - Tabulated design values and procedures for determining declared and design thermal values" is a CEN-endorsed international standard that defines methods and tabulated data for the thermal and moisture-related (hygrothermal) properties of thermally homogeneous building materials and products. It supplies procedures to derive declared and design thermal values, and conversion coefficients to adapt measured or declared values to different service conditions. Key validity ranges: design ambient temperatures −30 °C to +60 °C; conversion coefficients for temperature and moisture valid for mean temperatures 0 °C to 30 °C.
Key Topics
- Declared thermal value: expected thermal property based on measured data at reference temperature/humidity and specified confidence level.
- Design thermal value: thermal conductivity or resistance adapted for specific internal and external design conditions.
- Conversion procedures:
- Temperature conversion (coefficients for mean temperatures 0–30 °C).
- Moisture conversion (moisture-dependent adjustments).
- Age conversion and considerations for natural convection in insulating materials.
- Tabulated design data: numerical tables (Clause 8, Tables 3–5) of design thermal and moisture values for commonly used materials and products, compiled and updated from EN 12524.
- Normative test references: ISO 7345 (quantities/definitions), ISO 8990 (guarded hot box), ISO 12572 (water vapour transmission).
- Annexes: Annex A (conversion coefficients review, e.g., XPS and PU), Annex B (calculation examples), Annex C (statistical methods).
Applications
EN ISO 10456:2007 is used where reliable hygrothermal input data are required for:
- Heat and moisture transfer calculations and hygrothermal modelling of building components.
- U‑value and thermal bridging assessments for building envelopes.
- Energy performance and compliance with building regulations and certification schemes.
- Material specification and product declarations (manufacturers deriving declared/design values).
- Quality control and laboratory testing when converting measured data to in‑service conditions.
Who should use it
- Building designers, energy assessors and consultants
- Thermal and hygrothermal modelling engineers
- Insulation and building product manufacturers
- Test laboratories and standards bodies
- Regulatory authorities and certification bodies
Related standards
- ISO 7345 - Thermal insulation: physical quantities and definitions
- ISO 8990 - Determination of steady‑state thermal transmission properties
- ISO 12572 - Water vapour transmission properties
- EN 12524 - Building materials - Hygrothermal properties (source for tabulated data)
EN ISO 10456:2007 provides authoritative, conversion‑ready hygrothermal data and procedures that improve consistency and accuracy when specifying materials, performing energy calculations, or preparing product thermal declarations.
