ISO 22007-7:2023

Overview

ISO 22007-7:2023 - "Plastics - Determination of thermal conductivity and thermal diffusivity - Part 7" - specifies a transient, plane-heat-source method for measuring thermal effusivity of plastics and polymer-based materials. The method uses a self-heated planar probe (combined heater and resistance thermometer) embedded in or between specimens and records the transient temperature response after a single-step heat pulse. The standard covers materials with thermal effusivity roughly from 40 to 40 000 W·s1/2·m−2·K−1 and temperatures from 50 K to 1000 K.

Key topics and technical requirements

• Measurement principle: Single-step heat pulse with a planar probe acting as both heater and temperature sensor; analysis of temperature vs. time to derive the normal-direction thermal effusivity (b = sqrt(λ · ρ · cp)).
• Two experimental configurations:
  • Configuration A (rod-shaped specimens) - for higher-effusivity materials (≈ > 1 000 W·s1/2·m−2·K−1). Typical cross-section area ~7 mm² up to ~1 000 mm²; rod lengths ~3 mm to ~100 mm. Probe cross-section should match specimen cross-section.
  • Configuration B (bulk specimens) - for lower-effusivity materials (≈