Thermal Effusivity Meter

Portable Thermal Effusivity Meter for Textiles, Fabrics, and Solids. 

The TPS-EFF (Transient Plane Source-EFFusivity) is a portable meter for direct determination of thermal effusivity of textiles and other low effusivity materials, in accordance with ASTM D7984-16. With a single measurement of 2 or 10 seconds in duration, materials can be accurately measured for thermal effusivity.

The TPS-EFF uses a single-sided 30 mm diameter TPS sensor and short test times, to ensure one-dimensional heat flow. During the measurement, the sensor is heated using a constant current source, while the temperature rise of the sample is simultaneously recorded with time, by monitoring the change in electrical resistance of the wire spiral. The slope of temperature against a special function of time, is used to calculate the thermal effusivity of the material. For materials of relatively high effusivity, the slope will be lower, than materials of low effusivity.


  • Follows International Standard ASTM D7984-16
  • Portable, Economical, and Accurate
  • Easy to use
  • Test time 2 and 10 seconds
  • No user calibrations required


Materials Textiles, Fabrics and Solids
Measurement Capabilities 1-Dimensional
Thermal Effusivity Range 35 to 1700 W√s/m2K
Measurement Time 2 and 10 seconds
Reproducibility 2%
Accuracy 5%
Temperature Range1 -10 to 50°C
Minimum Sample Size 35 mm diameter x thickness dependent on Effusivity
Maximum Sample Size Unlimited
Moisture Range 0 to 90% (non-condensing)
Sensor Diameter 30 mm
Standards ASTM D7984-16
Test Method Transient Plane Source (TPS)