Thermal Effusivity Testing Services

ASTM D7984

What is Thermal Effusivity?

Thermal effusivity (also known as thermal inertia) describes the heat storing or dissipating capacity of a given material and has units of (Ws½/m²K). It is used to describe the one-dimensional heat transmission between two closely associated and touching objects. Thermal effusivity (typically denoted as e) combines thermal conductivity (k), density and heat capacity (Cp) into one value.

Why is Thermal Effusivity Important?

Our skin’s thermoreceptors give us good information about perceived feel, although highly variable between individuals. Thermal effusivity measurements quantifies warm and cool feel for you, making what was previously subjective into a metric that can be quantitatively measured. We are an industry leader in the measurement of thermal effusivity and experts in its many applications. TAL has worked with industry to establish ASTM D7984 as a global standard for characterizing the warm feel/cool touch of textiles. Quantifying comfort is of immense value and is helping to improve product design and give groups a competitive edge in a highly competitive market.

What Methods are Available for Thermal Effusivity Testing?

For thermal effusivity measurements there is a clear choice in method selection. The Modified Transient Plane Source (MTPS) provides a direct measurement without the need for additional user input and can accommodate a wide range of samples sizes. Particularly applicable to textile materials, the MTPS is the only method of analysis that conforms to ASTM D7984. For groups needing to characterize the warm feel/cool touch of their materials, the choice is simple – MTPS.

C-Therm MTPS Sensor

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    Thermal Effusivity Testing

    We offer MTPS testing for the thermal effusivity and conductivity of fabrics and other materials. Below is a selection of the measurement requirements for thermal effusivity testing services.


    Recommended Methods

    Modified Transient Plan Source (MTPS)

    Measurement Range 5 – 40000 Ws1/2/m2K
    Sample Size Min. diameter of 18 mm.
    Min. thickness is dependent on the thermal conductivity.
    Temperature Range -50 – 200 °C
    Recommended Material types Textiles, solids and powders
    ASTM/ISO/EN Standards ASTM D7984

    Other methods may be available. Contact us at info@thermalanalysislabs.com or call (506) 457-0498 to discuss.

    • Newell Brands- Writing (Sharpie, PaperMate, PrismaColor, Elmer's)

      Thermal Analysis Labs has provided great service for all our materials testing needs by providing quick turn-around testing results while also providing the service for a reasonable cost. TAL’s professional approach to our material testing request has also provided great insight to the materials being tested and the best method to achieve the measurements. TAL has been an invaluable resource for our product development process.

      Stan Chudzik,
      Fellow Engineer, Advanced Concepts

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