Tx Thermal Effusivity Touch Tester

SKU: TXTETT Category:

Quantify the Warm-Feel / Cool-Touch Sensation of Textiles and Fabrics according to ASTM D7984

C-Therm’s touch tester is the only product for quantifying touch performance that fully complies with ASTM D7984. The Tx Touch Tester is employed by the top global sports apparel brands and textile testing labs including Adidas, Columbia Sportswear, Marks (Canadian Tire), Intertek, the Taiwan Textile Research Institute, and Bureau Veritas.

Touch is a critical performance attribute in material selection and quality control for bedding textiles, automotive, and fabrics apparel sectors. Thermal effusivity quantifies how materials feel to the touch, whether warm or cool, taking away the guesswork for industries that want to improve product performance.

This testing was traditionally performed using panels of people, who could subjectively verify whether one material felt warmer or cooler than another, as the thermoreceptors in the human hand can detect the difference between materials. However, such human touch testing is extremely subjective to people doing the touch testing, and having an instrument that can accurately measure thermal effusivity takes away this variability for testing a wide range of materials for different use cases and applications.

Materials with a low thermal effusivity feel warmer and materials with a higher thermal effusivity feel cooler. Testing materials for their thermal performance and touch properties has a broad range of applications, including activewear, diapers, denim, and personal protective clothing, to name a few.

Thermal effusivity testing for textiles has been standardized by the American Society for Testing Materials (ASTM). The industry led standard, ASTM D7984, utilizes C-Therm’s patented Modified Transient Plane Source (MTPS) technology for measurement. C-Therm’s MTPS sensor, employed by the TX Effusivity Touch Tester, is the only standardized instrument for characterizing the thermal touch properties of textiles and other materials.


Tx Effusivity Touch Tester: Simplify Thermal Effusivity Testing with the Modified Transient Plane Source (MTPS) Technique

Measure the thermal effusivity of textiles with the Tx Effusivity Touch Tester by C-Therm, creators of industry-leading thermal conductivity equipment who helped develop the ASTM D7984 standard. The Tx Effusivity Touch Tester is the only instrument that conforms to the standard.

This thermal effusivity instrument is equipped with the patented Modified Transient Plane Source (MTPS) sensor, a single-sided sensor that measures the thermal effusivity of a broad range of textiles and fabrics in 1 to 3 seconds. Industry leaders rely on the MTPS sensor to test product performance including Mark’s, Under Armour, adidas, Columbia, Tempur Sealy, and 3M.


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How It Works

The Tx Effusivity Touch Tester employs the Modified Transient Plane Source (MTPS) technique. The one-sided, interfacial heat reflectance sensor applies a momentary constant heat source to the sample. Thermal effusivity is measured directly, providing a detailed overview of the thermal characteristics of the sample.


Principles of Operation

Trident’s primary sensor employs the Modified Transient Plane Source (MTPS) technique in characterizing the thermal conductivity and effusivity of materials. It employs a single-sided, interfacial heat reflectance sensor that applies a momentary constant heat source to the sample. Typically, the measurement pulse is between 1 to 3 seconds. Thermal conductivity and effusivity are measured directly, providing a detailed overview of the heat transfer properties of the sample material.


  1. A known current is applied to the sensor's spiral heating element, providing a small amount of heat.
  2. A guard ring surrounds the sensor coil to support a one-dimensional heat transfer into the sample. The applied current results in a rise in temperature at the interface between the sensor and the sample, which induces a change in the voltage drop of the sensor element.
  3. The rate of increase in the sensor voltage is used to determine the thermal properties of the sample. The voltage is factory-calibrated to temperature. The thermal conductivity is inversely proportional to the rate of increase in the temperature at the point of contact between the sensor and the sample. The voltage is used as a proxy for temperature and will rise more steeply when lower thermal conductivity materials (e.g. foam) are tested. Conversely, the voltage slope will be flatter for higher thermal conductivity materials (e.g. metal). With the C-Therm Tx Effusivity Touch Tester, tabular thermal conductivity results are reported in real-time making thermal conductivity measurement fast and easy. No regression analysis is required.