Overview
SIST EN ISO 10211:2017 (ISO 10211:2017) specifies detailed methods for calculating thermal bridges in building construction. It defines both three‑dimensional (3‑D) and two‑dimensional (2‑D) geometrical models and the numerical procedures needed to determine:
- heat flows for assessment of overall building or element heat loss, and
- minimum surface temperatures to evaluate the risk of surface condensation.
The standard sets the geometrical boundaries and subdivisions of models, thermal boundary conditions, and required thermal values and relationships. It assumes that physical properties are independent of temperature and that there are no internal heat sources within the element. ISO 10211:2017 can also be used to derive linear and point thermal transmittances and surface temperature factors.
Key topics and technical requirements
- Model definitions: detailed rules for 3‑D and 2‑D geometrical modelling (cut‑off planes, subdivisions, auxiliary planes).
- Input data specifications: required thermal conductivities, surface resistances, boundary temperatures, equivalent conductivity for air cavities and quasi‑homogeneous layers.
- Assumptions: material properties considered temperature‑independent; no internal heat sources.
- Calculation method: numerical solution techniques, heat‑flow balance between material cells and environment, rules for cut‑off planes and partitioning.
- Outputs: total heat flow, minimum surface temperatures, thermal coupling coefficients, linear/point thermal transmittances, and surface temperature factors.
- Simplification rules: conditions under which geometrical or material simplifications (e.g., quasi‑homogeneous layers) are acceptable.
- Context in EPB standards: positions ISO 10211 within the set of Energy Performance of Buildings (EPB) standards (see ISO 52000‑1).
Practical applications and users
ISO 10211:2017 is intended for professionals who require rigorous assessment of thermal bridging and surface temperatures, including:
- Building designers and architects - to reduce heat loss and condensation risk in details (junctions, corners, service penetrations).
- Energy assessors and modelers - to derive accurate linear/point thermal transmittances for whole‑building energy calculations and certification.
- Building physicists and consultants - for detailed thermal simulations and compliance with EPBD/energy‑performance requirements.
- Product manufacturers and façade/wall system designers - to evaluate junction performance and support product data.
- Retrofit planners and regulators - to quantify thermal bridging effects in renovation and verification of regulatory compliance.
Typical uses include compliance with energy performance regulations, detailed design of thermal insulation systems, assessment of condensation risk at junctions, and generation of input data for building energy simulation tools.
Related standards
- ISO 52000‑1 (modular structure of EPB standards) - shows ISO 10211’s role within EPB methodology.
- EPB standards developed under ISO/TC 163 and CEN/TC 89 - ISO 10211 is part of the EPB suite for energy performance of buildings.
Keywords: ISO 10211:2017, thermal bridges, heat flow, surface temperatures, linear thermal transmittance, point thermal transmittance, condensation risk, building energy performance, EPB standards.