Decagon KD2 Pro

– thermal properties instrument

  • Soil Thermal ConductivityThermal Conductivity
  • Thermal Resistivity
  • Thermal Diffusivity
  • Specific Heat
  • Hire Options Available


The KD2 Pro is a fully portable field and lab thermal properties analyzer developed out of 30+ years of research experience on heat and mass transfer in soils and other porous materials. Tested against known standards, the KD2 Pro uses the transient line heat source method to measure thermal conductivity, resistivity, diffusivity, and specific heat.



The compact KD2 Pro controller is much more than a simple readout for time and temperature. A proprietary algorithm fits time and temperature data with exponential integral functions using a nonlinear least squares method. This fully mathematical solution delivers thermal conductivity/resistivity to within ±10%.


Soil Thermal Resistivitycorrect

The KD2 Pro corrects for temperature drift. Temperature changes of a thousandth of a degree per second—the sun warming the soil, or someone walking into the lab— destroy the accuracy of thermal properties calculations. Unlike other thermal needle systems, the KD2 Pro corrects for linear temperature drift that cause erroneous readings.


Complies with ASTM, and IEEE Standards

The KD2 Pro complies fully with ASTM D5334-14.
A certificate of compliance can be downloaded at


feature specification
Thermal Conductivity/Resistivity ± 5 to ± 10%
Specific Heat ± 10%
Thermal Diffusivity ± 10%
measurement range
Thermal Conductivity 0.02 to 4 Wm-1 C-1
Thermal Resistivity 0.25 to 50mC W-1
Specific Heat 0.5 to 4 MJ m-3 C-1
Thermal Diffusivity 0.1 to 1.0 mm2s-1
general specifications
Measurement Speed 1, 2, 5, & 10 min. read times depending on measurement type
Data Storage 4,095 readings, flash memory
Compliance to Standards ASTM Standard D5334-08 and IEEE Standard 442-1981
Operating Environment -50° to 150°C
Power Supply 4 x AA Batteries
Auto Read Mode Users can collect unattended data at user-defined intervals in the auto-read mode
Display Liquid Crystal Display (LCD) 7.5 cm x 4 cm
Case Dimensions 15.5 cm x 9.5 cm x 3.5 cm
Calibration Each KD2 Pro comes factory calibrated and includes performance verification standards
Included Accessories KS-1 Thermal Conductivity/Resistivity sensor (for liquids) | TR-1 Thermal Conductivity/Resistivity sensor (for solids) | SH-1 Dual-Needle Thermal Diffusivity and Specfic Heat sensor (for solids) | User's manual | Pelican carrying case | Readout stand | Performance verification standards | Thermal grease | Drill bit for drilling pilot holes in materials | Concrete pilot pin | KD2 Pro download utility | RS232 cable