Transient Line Source TLS-100

The TLS-100 is a portable meter used to measure thermal conductivity and thermal resistivity of a variety of samples, including soil, rocks, concrete, and polymers.

Standard 100 mm Sensor

Each TLS-100 comes equipped with the standard 100 mm sensor for testing of soil, soft materials, polymers and easy to drill materials. The needle sensor is fully inserted into an isothermal sample and a measurement is made with the push of a button. After 180 seconds, results are displayed for thermal conductivity and thermal resistivity. Saved results can also be exported to a computer, via convenient utility software and USB connection.

Standard 50 mm Sensor

The 50 mm sensor was designed for testing hard samples, like rock and concrete. Drilling the required 4 mm diameter x 50 mm hole in rigid samples is easy with the provided masonry drill bit. 

Optional 150 mm Sensor

Optional 150 mm sensor for in-lab and in-field testing of soil and soft materials according to IEEE 442-2017. It provides results about thermal conductivity and thermal resistivity.

Standard 100mm – vCp Sensor

The TLS 100 mm – vCp Sensor was designed for testing the thermal conductivity, thermal diffusivity, and specific heat of soil, soft or easy to drill materials.


MaterialsSoil, Rock, Concrete, & Polymers
Thermal Conductivity0.1 to 5 W/m•K
Thermal Resistivity0.2 to 10 m•K/W
Measurement Time3 min
Reproducibility± 2%
Accuracy± 5%
Temperature Range-40 to 100°C
Stanisław Gołębiewski
Application Engineer
Stanisław Gołębiewski
Application Engineer