Overview
EN ISO 23993:2010 - "Thermal insulation products for building equipment and industrial installations - Determination of design thermal conductivity" - gives standardized methods to convert a product’s declared thermal conductivity into a design thermal conductivity for use in thermal-performance calculations. The methods apply to operating temperatures from −200 °C to +800 °C and use conversion factors that account for real-world influences on insulation performance. The standard is intended for CEN/ISO use in building equipment and industrial installations.
Key topics and requirements
- Declared → Design thermal conductivity: Procedures to start from the declared thermal conductivity (as determined per ISO 13787) and calculate a conservative design value for engineering calculations.
- Conversion factors (F): Defined factors for common influences that change thermal conductivity in service, including:
- Temperature dependence (non-linearity of λ over the operating range)
- Moisture effects
- Ageing
- Compression / mechanical stress
- Convection and thickness effects
- Regular joints and insulation-related thermal bridges (e.g., spacers)
- Equation-based approach: General equations combine declared λ and conversion factors to produce the design λ to be used in heat-loss and thermal-performance models.
- Annexes and guidance: Normative Annex A lists conversion factors; informative Annex B gives calculation examples; Annex C provides approximate values and material guidance.
- Scope limits: Valid for temperatures −200 °C to +800 °C; conversion factors apply within specified temperature ranges in the clauses or annexes.
Practical applications
- Use EN ISO 23993:2010 to derive conservative thermal conductivity values for:
- Heat-loss calculations of piping, ductwork, tanks and other building equipment.
- Thermal design of industrial installations (process piping, cryogenic systems, high-temperature systems).
- Energy performance simulations and compliance documentation where insulation behaviour under operating conditions matters.
- Typical users:
- Thermal engineers and energy modelers
- Insulation manufacturers and product certifiers
- Specifiers and consultants preparing design briefs and tender documents
- Testing laboratories and conformity assessment bodies
Related standards
- ISO 13787 - Determination of declared thermal conductivity (referenced for declared λ)
- ISO 7345, ISO 8497, ISO 9053, ISO 9229 - referenced for terminology, properties and test methods
- EN/ISO series on thermal performance of building components
EN ISO 23993:2010 helps ensure that thermal-performance calculations reflect realistic in-service behavior, improving reliability of heat-loss estimates, energy models, and insulation system design.