Overview
ISO 9869-2:2018/Amd 1:2021 is an important amendment to the international standard focused on the in-situ measurement of thermal resistance and thermal transmittance in building elements. Specifically, this standard addresses the infrared (IR) method for frame structure dwellings, providing detailed guidance on the calculation of uncertainty analysis to improve measurement accuracy in thermal insulation assessments.
Developed by ISO Technical Committee ISO/TC 163, this amendment introduces an example for calculating the uncertainty in thermal transmittance measurements using infrared technology. This enhances the reliability of in-situ thermal performance evaluations in building frameworks, which is critical for energy efficiency and sustainable building design.
Key Topics
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Thermal Resistance and Thermal Transmittance Measurement
The document focuses on measuring heat transfer through building elements using the infrared method in real conditions, especially for framed structures. It guides on best practices for thermal insulation assessment without destructive testing.
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Infrared Method Application
ISO 9869-2 Amendment 1 expands on the use of IR cameras coupled with heat flux sensors and temperature probes to measure surface and environmental temperatures accurately.
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Uncertainty Analysis Calculation
A major contribution of this amendment is the detailed example demonstrating how to calculate the combined standard uncertainty and expanded uncertainty of thermal transmittance measurements. This includes:
- Identification of uncertainty factors from heat flow sensors, IR cameras, data loggers, and thermocouples
- Application of mathematical formulas for uncertainty combining sensitivity coefficients and measurement errors
- Preparation of uncertainty calculation sheets for practical use
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Calibration and Accuracy Enhancements
The annex emphasizes that while IR cameras alone may lead to up to 40% measurement errors, using calibrated thermocouples significantly improves accuracy and reduces uncertainty in thermal transmittance results.
Applications
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Building Energy Efficiency Assessments
The standard is highly relevant for professionals conducting energy audits and thermal performance tests to optimize insulation and reduce heating/cooling loads.
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Quality Control in Construction
Construction firms and inspectors can utilize this IR method and uncertainty analysis to verify insulation compliance and identify thermal bridging in frame structures.
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Research and Development of Building Materials
Material scientists and engineers working on innovative insulation products benefit from standardized measurement methods ensuring reliable in-situ thermal resistance data.
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Retrofitting and Renovation Projects
In existing building evaluations, the non-invasive IR technique supported by rigorous uncertainty calculations facilitates cost-effective diagnosis of insulation effectiveness.
Related Standards
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ISO 9869-1 - Covers the general principles for in-situ measurement of thermal resistance and transmittance using heat flow methods.
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ISO 6946 - Specifies the calculation methods for thermal resistance and transmittance of building components.
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ISO 13786 - Focuses on thermal performance of building components, including dynamic properties influencing energy use.
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ISO/IEC Directives, Part 1 and 2 - Outline procedural and editorial rules for standards development and maintenance, referenced for document preparation compliance.
Keywords: ISO 9869-2 amendment, thermal insulation measurement, infrared method, thermal transmittance uncertainty, building elements, in-situ thermal resistance, frame structure dwelling, heat flow sensor calibration, energy efficiency standards, building thermal performance.
Open preview (PDF)Thermal insulation — Building elements — In-situ measurement of thermal resistance and thermal transmittance — Part 2: Infrared method for frame structure dwelling — Amendment 1: Example of calculation of uncertainty analysis