Overview
ISO 29466:2022 specifies a reference method for the determination of thickness of full‑size thermal insulating products for building applications. The standard defines the equipment, specimen preparation, conditioning, measurement procedure and reporting requirements used by laboratories and manufacturers to obtain consistent, comparable thickness data. It also permits alternative methods (e.g., for quality control) provided they are correlated with this reference method (see Annex B).
Key topics and technical requirements
- Scope: Applies to full‑size thermal insulating products; reference method for thickness measurement.
- Principle: Thickness is the perpendicular distance between a hard flat reference surface and a pressure plate resting freely on the specimen.
- Apparatus:
- Dial gauge mounted on a rigid frame and base plate; maximum permissible error 0.5 mm.
- Square pressure plate 200 mm × 200 mm applying total pressures of (50 ± 1,5) Pa or (250 ± 5) Pa (including dial gauge force).
- Specimen preparation and conditioning:
- Full‑size product used; cutting allowed if necessary.
- Store specimens at least 6 h at (23 ± 5) °C; for disputes use (23 ± 2) °C and 50 ± 5 % RH.
- Tropical alternative: (27 ± 2) °C and 65 ± 5 % RH - must be stated in the test report.
- Compressed products: follow Annex A (specific preparation/drop-and-wait procedure) before measurement.
- Measurement procedure:
- Position specimen with facing/coating against the baseplate if applicable.
- Apply pressure plate and take measurements at designated points (number of measurements depends on specimen length: 2 for ≤600 mm; 4 for >600 mm up to 1 500 mm; +1 for each additional 500 mm).
- Record individual readings to instrument accuracy.
- Results and reporting:
- Express thickness in millimetres to the nearest millimetre as the mean of all points.
- Test report must reference ISO 29466:2022 and include product ID, conditioning, test conditions, pressure used, individual values and mean, and any deviations.
Applications and users
- Manufacturers of thermal insulation (mineral wool, foam boards, rolls, etc.) for product specification and quality control.
- Third‑party test laboratories performing conformity testing and product certification.
- Architects, specifiers and building professionals verifying product dimensions for thermal design and installation tolerances.
- Regulatory and compliance bodies assessing conformity with product standards that reference ISO 29466:2022.
Related standards and notes
- ISO 29466:2022 is a reference method and is intended to be used alongside relevant product standards (which may specify pressures, number of specimens, or tighter tolerances).
- Developed by ISO/TC 163 in collaboration with CEN/TC 88; consult the product‑specific standard for any higher accuracy or alternative test positions.
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