Overview
ISO 13787:2003 specifies how to determine and verify the declared thermal conductivity (as a function of temperature) for thermal insulation products used on building equipment and industrial installations. It defines the form of declared values (curve or table), measurement principles, verification procedures and informative annexes with alternative and statistical methods. Not applicable to building-envelope insulation (see ISO 10456 for that application).
Key topics and technical requirements
- Declared thermal conductivity: Manufacturer supplies a temperature-dependent curve or table representing expected thermal conductivity for the product conditioned at standard atmosphere (23 °C, 50 % RH).
- Measurement methods: Measurements carried out per ISO 8301, ISO 8302 or EN 12667 for flat specimens, and EN ISO 8497 for cylindrical specimens.
- Temperature coverage and intervals:
- Measurements at three or more mean temperatures at least.
- For mean temperatures ≤ 500 °C: measurement intervals ≤ 100 K (and closer around inflexion points).
- For mean temperatures > 500 °C: intervals ≤ 200 K.
- Temperature difference during test:
- Flat specimens: ΔT between hot and cold faces 10 K to 40 K (choose ΔT to maximize accuracy).
- Cylindrical specimens: ΔT not less than 10 K.
- Verification procedure:
- Select three different samples, measure test specimen from first sample and compare with proposed declared curve/table.
- If all measured values ≤ declared values → pass.
- If any measured value exceeds declared by ≥ 10 % → fail.
- If some exceed but < 10 %, measure two additional specimens (one from each remaining sample), convert/average results and re-evaluate per the standard’s decision rules.
- Data handling rules:
- No extrapolation beyond measured temperature range.
- Measured thermal conductivities rounded up to nearest 0.001 W/(m·K).
- Informative annexes:
- Annex A: curve comparison method.
- Annex B: optional statistical method to establish declared curve.
- Annex C: illustrative verification examples.
Practical applications
- Establishing manufacturer-declared thermal conductivity curves for product data sheets and performance declarations.
- Quality control and factory acceptance testing by test laboratories.
- Supporting thermal performance calculations for piping, HVAC equipment and industrial process insulation systems.
- Basis for procurement specifications, compliance checks and certification of insulation products used on mechanical/industrial installations.
- Insulation manufacturers and product developers
- Independent testing laboratories and certification bodies
- Mechanical/HVAC and industrial insulation engineers
- Specification writers, procurement teams and regulators
Related standards
- ISO 10456 - procedures for building-envelope materials (different scope)
- ISO 8301, ISO 8302, EN 12667, EN ISO 8497 - referenced test methods for thermal conductivity measurements
Keywords: ISO 13787, thermal conductivity, declared thermal conductivity, thermal insulation, building equipment, industrial installations, thermal conductivity curve, measurement, verification.