Overview
ISO 10293:1997 specifies a standardized test method for the determination of steady-state U values (thermal transmittance) of multiple glazing using the heat flow meter method. U value testing is essential in building construction, where energy efficiency and thermal insulation performance of glazing systems are increasingly important for compliance and sustainability. This standard applies to multiple glazing units with flat, parallel surfaces, and can also be extended to patterned glass surfaces considered flat. The method outlined enables objective comparison and evaluation of thermal performance for different glazing products in typical operational conditions.
Key Topics
- Thermal Transmittance (U Value): Defines the rate of heat transfer through a material per unit area and temperature difference, indicating how well glazing units insulate buildings.
- Heat Flow Meter Method: Utilizes a calibrated test apparatus to measure heat flow through glazing samples, offering precise and repeatable results.
- Sample Preparation and Measurement: Details strict requirements for specimen dimensions, flatness, and conditioning to ensure reliable, standardized testing.
- Surface Heat Transfer Coefficients: Addresses variables like internal and external surface heat transfer to ensure comparability of test results.
- Reporting Requirements: Specifies mandatory test report elements for traceability and assurance, including sample identification, test conditions, measurement results, and critical dimensions.
Applications
ISO 10293:1997 is widely utilized in the following practical scenarios:
- Energy Efficiency Certification: Verifying compliance of insulating glass units (IGUs) and multi-pane glazing with national and international building energy codes.
- Product Development: Assisting manufacturers of architectural glass and window systems in benchmarking and optimizing thermal performance.
- Building Design and Specification: Supporting architects, builders, and specifiers in selecting suitable glazing products for optimal thermal insulation in residential, commercial, and industrial buildings.
- Quality Assurance: Establishing reproducible quality control benchmarks in production or third-party testing laboratories.
- Environmental Sustainability: Contributing to green building initiatives by facilitating accurate thermal measurement for façade and window products.
Related Standards
To ensure comprehensive evaluation and consistency in the determination of thermal properties of glazing, the following international standards are closely related:
- ISO 8301:1991 - Thermal insulation - Determination of steady-state thermal resistance and related properties - Heat flow meter apparatus: Basis for heat flow meter method used in ISO 10293.
- ISO 8302:1991 - Thermal insulation - Determination of steady-state thermal resistance and related properties - Guarded hot plate apparatus: Calibration reference for thermal resistance measurement.
- ISO 10292:1994 - Glass in building - Calculation of steady-state U values (thermal transmittance) of multiple glazing: Complements ISO 10293 by providing procedures for calculated rather than measured U values.
By adopting ISO 10293:1997, organizations in the building and glazing industry can ensure transparent, reliable, and comparable U value measurements, reinforcing both regulatory compliance and market confidence in the energy efficiency of glazing systems.
Open preview (PDF)Glass in building — Determination of steady-state U values (thermal transmittance) of multiple glazing — Heat flow meter method
