ISO 10211:2017

Overview

ISO 10211:2017 - Thermal bridges in building construction - Heat flows and surface temperatures - Detailed calculations - defines rigorous procedures for numerical calculation of heat flows and surface temperatures associated with thermal bridges. The standard describes both 3‑D and 2‑D geometrical models, the geometrical boundaries and subdivisions, thermal boundary conditions, and required thermal values and relationships. It is primarily intended to assess overall heat loss (including derivation of linear and point thermal transmittances) and to evaluate minimum internal surface temperatures for the risk of surface condensation.

Key assumptions of ISO 10211:2017:

• Material physical properties are considered independent of temperature.
• No internal heat sources are present within the modeled building elements.

Key Topics and Requirements

• Geometrical modelling: Specifications for cut‑off planes, dimension systems, auxiliary planes and rules to simplify or partition 2‑D and 3‑D models.
• Boundary conditions and input data: Defined requirements for surface resistances, boundary temperatures, thermal conductivities (including quasi‑homogeneous layers and equivalent air cavity conductivities).
• Calculation method: Numerical solution techniques, calculation time intervals, heat flow exchanges between cells, and procedures to obtain temperature distributions.
• Derived parameters: Methods to derive thermal coupling coefficients, linear and point thermal transmittances, and surface temperature factors from detailed calculations.
• Reporting and validation: Required output data, reporting templates (Annex A normative template; Annex B informative defaults), validation procedures (Annex C) and worked examples (Annex D, E).

Practical Applications and Users

ISO 10211:2017 is used to:

• Quantify additional heat loss due to thermal bridges in building envelopes.
• Calculate minimum internal surface temperatures to assess surface condensation and mold risk.
• Derive linear thermal transmittance (Ψ‑values) and point thermal transmittance for energy performance assessment and compliance calculations.
• Support design optimization of junctions (e.g., wall‑to‑floor, window frames, balconies) and specification of insulation details.

Primary users:

• Architects and building envelope designers
• Thermal engineers and energy modelers
• Building physicists and consultants
• Regulators and certification bodies setting energy performance requirements

Related Standards

• ISO 52000‑1 (EPB modular structure and context for energy performance of buildings)
• CEN/TS 16629 (basis for the 2017 revision)
• Other EPB (Energy Performance of Buildings) standards referenced for consistent methodology

ISO 10211:2017 is essential for professionals needing standardized, repeatable detailed calculations of thermal bridges to improve building energy performance and to prevent moisture/condensation issues.