The THW method employs a line heat source sensor that applies a momentary constant heat source to the sample. Typically, the measurement pulse is between 1 to 3 seconds. The temperature behavior as a function of time is analyzed with an absolute model to give thermal properties of the sample. Thermal conductivity and diffusivity are measured directly, providing a detailed overview of the heat transfer properties of the sample material. This method is recommended for testing heat-transfer fluids used in the automotive sector. Measurement Range 0.01 to 2 W/mK Sample size Min. volume of 40 mL Temperature range -40 to 200 °C Material types Liquids, gels, and powders ASTM/ISO/EN Standards ASTM D7896-19
