Overview
EN ISO 29768:2022 - "Thermal insulating products for building applications - Determination of linear dimensions of test specimens" - specifies how to measure the linear dimensions of test specimens taken from thermal insulation products. It defines suitable measuring equipment, minimum accuracy requirements, test conditions (including alternative tropical conditions), and basic procedures to obtain reliable, repeatable linear measurements for use in thermal‑insulation testing and product verification. This European adoption supersedes EN 12085:2013 and is identical to ISO 29768:2022.
Key topics and requirements
- Scope and principle: Measure the distance between defined points, parallel lines or planes on test specimens using apparatus that provides the required accuracy.
- Approved apparatus:
- Dial gauge (reading at least 0.05 mm; measuring pressure ≤ 1 kPa).
- Micrometer (reading at least 0.05 mm) with a device to indicate onset of contact force (example: low‑pressure aluminum plate arrangement).
- Sliding caliper (reading at least 0.1 mm), used only if it does not deform the specimen.
- Metal rule or metal tape (graduated in millimetres; reading to at least 0.5 mm).
- Accuracy guidance:
- Tabled maximum permissible errors are given both in absolute mm and percentage terms to guide instrument selection (e.g., dial gauge/micrometer for highest accuracy, sliding caliper for medium accuracy, metal tape/rule for coarse measurements).
- Specimen preparation and conditions:
- Number, size and conditioning follow the relevant product/test standard. If no product standard exists, parties should agree sampling.
- Tropical test conditions (if applicable) are specified as (27 ± 2) °C and (65 ± 5) % RH and must be recorded in reports.
- Measurement procedure:
- At least two measurement locations per specimen, widely separated to obtain representative mean values.
- Methods described for use of dial gauge, micrometer, caliper and rule/tape to minimise measurement error and specimen deformation.
- Reporting and accuracy:
- Results, equipment, test conditions and measurement locations are recorded; accuracy and conformity to the selected method are addressed (see clauses on calculation, expression of results and accuracy).
Applications and users
- Practical for laboratories and manufacturers performing dimensional checks on insulation test specimens prior to thermal performance testing (e.g., thermal conductivity, heat flow).
- Used by: test laboratories, certification bodies, product manufacturers, quality control engineers, R&D teams and standards committees involved in building insulation.
- Keywords: EN ISO 29768:2022, thermal insulating products, linear dimensions, measurement accuracy, dial gauge, micrometer, sliding caliper, insulation testing.
Related standards
- ISO 29465 and ISO 29466 - procedures for measuring dimensions of full‑size insulation products (referenced as complementary standards).
- EN ISO 29768:2022 replaces EN 12085:2013 and was prepared in collaboration between ISO/TC 163 and CEN/TC 88.
This standard ensures consistent, traceable linear measurements of insulation test specimens to support reliable thermal testing and product conformity assessment.