Overview
EN ISO 18099:2022 - "Thermal insulating products for building equipment and industrial installations - Determination of the coefficient of thermal expansion" (CEN adoption of ISO 18099:2022) specifies the equipment and procedures to determine the coefficient of linear thermal expansion of thermal insulating products. The standard covers testing across a wide temperature range (−196 °C to 850 °C), subject to the limitations of the specimens, and excludes materials that change dimensionally due to loss of hydration water or other phase changes.
Key Topics
- Scope and exclusions: Applicable to thermal insulating products for building and industrial installations; not applicable when irreversible dimensional changes (e.g., dehydration, phase transitions) occur during the test.
- Test principle: Measurement of reversible linear dimensional changes as a function of temperature - either continuously over a temperature range or between two specified temperatures to obtain a mean coefficient.
- Apparatus requirements:
- Dilatometer (tube or rod type; vitreous silica commonly used)
- Micrometer calliper or displacement transducer for length measurement with specified accuracy
- Electrical furnace (for high temperatures) and test chamber (for low/cryogenic temperatures), each able to control mean specimen temperature and limit temperature-change rates to 1 °C/min
- Calibrated thermocouples connected to continuous recording devices (accuracy: ±0.5 K from −196 °C to 200 °C; ±1 K from 200 °C to 500 °C; ±2 K from 500 °C to 850 °C)
- Specimen preparation:
- Typical specimen size guidance (e.g., (50 ± 1) mm length with 10 mm cross-section), with dimensions chosen to match dilatometer geometry and product characteristics
- Conditioning and number of specimens as per product standard or agreement between parties
- Results and accuracy:
- Definitions for mean coefficient and instantaneous coefficient at temperature
- Reporting requirements and limits on measurement uncertainty
Applications
Who uses EN ISO 18099:2022 and why:
- Manufacturers of thermal insulation to validate dimensional stability with temperature changes
- Testing laboratories and quality control teams performing dilatometer tests
- Specifiers and engineers designing building services and industrial installations who need predictable thermal movement data
- R&D teams assessing new insulation materials across cryogenic to high-temperature applications
Practical use cases include thermal expansion data for pipe insulation, equipment insulation, cryogenic systems and high-temperature process lines.
Related Standards
- Supersedes EN 13471:2001 and integrates earlier ISO work (ISO 18099:2013).
- Prepared by ISO/TC 163 (Test and measurement methods) in collaboration with CEN/TC 88 (Thermal insulating materials and products).
Keywords: EN ISO 18099:2022, coefficient of thermal expansion, linear thermal expansion, thermal insulating products, dilatometer testing, temperature range −196 °C to 850 °C, thermocouple accuracy.
