SIST EN ISO 13786:2017 PDF

Overview

EN ISO 13786:2017 (ISO 13786:2017, corrected version 2018-03) defines methods to calculate the dynamic thermal characteristics of complete building components. It specifies which information on building materials and component assembly is required, gives calculation procedures for dynamic properties (such as periodic thermal transmittance and thermal admittance), and provides a simplified method for plane components made of homogeneous layers. The standard applies to whole building components - not to individual building materials or unfinished elements - because dynamic behaviour depends on the way materials are combined.

Key topics

• Dynamic thermal characteristics: definitions and standardized terms applicable to any building component (one- and multi-dimensional cases).
• Calculation methods: general procedures and numerical approach to compute time-dependent thermal responses of components.
• Heat transfer matrix: method for assembling layer and cavity contributions into a component-level heat transfer description.
• Periodic thermal transmittance and decrement factor: measures for assessing how cyclic thermal loads (daily or seasonal) are transmitted through components.
• Thermal admittance and periodic thermal conductance: dynamic surface-related properties used for thermal comfort and hygrothermal simulations.
• Areal heat capacity and heat capacity estimation: full procedures plus Annex C simplified methods for limited estimation cases.
• Simplified methods: specific simplified calculations for plane, homogeneous-layer components; Annex C gives approximations suitable for energy consumption estimation but not for precise product characterization.
• Reporting requirements: required output data, input selection, and templates (Annex A and B).

Practical applications

EN ISO 13786 is used to:

• Evaluate thermal performance of walls, roofs, floors and facade elements under dynamic (time-varying) conditions.
• Provide input data for building energy simulation and compliance checks against energy performance regulations (EPB/EPBD frameworks).
• Estimate the effect of thermal mass on indoor temperature swings and HVAC energy demand.
• Support product development where component-level dynamic properties are needed (with full methods rather than Annex C approximations).

Note: Annex C approximations are suitable for estimating energy consumption but are explicitly stated as inappropriate for formal product characterization.

Who should use this standard

• Building performance engineers and energy assessors
• Façade and envelope designers
• Thermal simulation specialists and researchers
• Manufacturers of prefabricated building components (for component-level assessments)
• Certification bodies and regulators implementing EPB/EPBD-related requirements

Related standards

• ISO 52000-1 (modular structure and context within EPB standards)
• EN ISO 13786:2007 (superseded)
• EPBD-related CEN/EPB standards for energy performance of buildings

Keywords: ISO 13786:2017, EN ISO 13786, dynamic thermal characteristics, thermal performance of building components, periodic thermal transmittance, thermal admittance, heat capacity, building energy simulation.