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Thermal Resistivity Test, ASTM 5334 & IEEE 442

Thermal Resistivity Test

Thermal Resistivity Test​, ASTM D5334 & IEEE 442

Thermal resistivity is a heat characteristic and a measurement of the difference in temperature at which a substance or object opposes the flow of heat. The reciprocal of thermal conductivity is thermal resistivity.

The design of underground power systems largely depends on an understanding of the thermal characteristics of the materials involved. Designing underground electric transmission lines, the designer can choose the cable’s size and capacity by considering how well the concrete and/or soils can disperse the heat generated by the utility.

Determination of thermal characteristics is based on two specified test methods:

  • ASTM D5334: Standard Test Method for Determination of Thermal Conductivity of Soil and Rock by Thermal Needle Probe Procedure
  • IEEE 442: Guide for Thermal Resistivity Measurements of Soils and Backfill Materials

Terra Testing, LLC conducts laboratory testing in accordance with both mentioned standards. In collaboration with engineers throughout the design phase, material producers for prequalification, and contractors, Terra Testing has carried out thermal resistivity testing on intact or bulk soil samples from all over the country to produce dry-out curves of thermal resistivity versus soil moisture content.

Please contact Ajit Govindan ( at 806-777-0786 to discuss your sampling and testing needs.