Thermal Resistivity Testing Services

SEP Geophysical provides high-quality thermal resistivity testing services to help our clients obtain an accurate and reliable picture of the subsurface. Thermal resistivity tests are typically performed as part of the testing requirements prior to the installation of high voltage power lines or heated pipelines.

Understanding the thermal behaviour of the subsurface is essential for many engineering projects. Thermal resistivity testing is a safe and effective way to obtain this information.

SEP Geophysical has extensive experience performing soil thermal resistivity tests in a variety of environments. Our advanced equipment and experienced personnel allow us to obtain accurate measurements even in difficult to access areas.

Applications of Thermal Resistivity Testing

There are several applications for measuring the thermal resistance of a material, a few of which are highlighted below:

Pipeline and Cable Route Selection and Design

Understanding the thermal behaviour of the soil is essential when it comes to pipeline and cable design and insulation. The data aids in the design of cable alignments, selection of cable backfill materials, and helps to determine the required thickness of insulation.

Helps to specify suitable cable backfill material
Specifies the minimum level of insulation required to minimise thermal dissipation
Informs decisions on whether to go above or below ground

Monitoring Changes in Soil Properties

Produces long-term records of changes in soil conditions that can be used to assess the impact of soil changes on infrastructure

Thermal Resistivity as a Proxy for Other Geotechnical Properties

Thermal resistivity is often used as a proxy for other geotechnical properties such as moisture content, void ratio, and unit weight. This is because these properties all have an impact on the material's ability to conduct heat.

Thermal Resistivity Testing FAQs

What is thermal resistivity?

Thermal resistivity is a measure of a material's ability to conduct heat. This property is important for many engineering applications, such as determining the suitability of materials for use in insulation or predicting heat flow through soils.

Thermal testing can be used to measure the thermal properties of a wide range of materials, including rocks, soils, concrete, and asphalt.

Is thermal resistivity the same as thermal conductivity?

No. Thermal resistivity (R) and thermal conductivity (k) are related by the equation R = 1/k. In other words, thermal resistivity is the inverse of thermal conductivity.

Why is thermal resistivity important?

The thermal properties of natural soils are critical in the design of underground power transmission systems.

The purpose of the TR testing is to provide the thermal conductivity (in W/m oK) or thermal resistivity (in oK cm/W) of soils at a selected depth. The tests, performed in-situ, are performed using the transient heat method and are conducted in accordance with IEEE Standard 442-1996.

How do you test thermal resistivity?

There are several thermal testing methods that can be used, but the most common is the transient heat method. This involves passing an electrical current through the porous materials and measuring the resulting temperature change.

The TEMpos Thermal resistivity meter used by SEP Geophysical is ASTM 5334- and IEEE 442-compliant and is engineered using ISO 2008 standards. It takes accurate readings of thermal conductivity, thermal resistance, thermal diffusivity, and specific heat.

What is the difference between thermal diffusivity and thermal conductivity?

Thermal diffusivity (α) is a measure of how quickly heat can travel through a material. It is related to thermal conductivity (k) by the equation α = k/ρC, where ρ is density and C is specific heat capacity.

In general, materials with high thermal conductivity will also have high thermal diffusivity. However, there are some materials, such as water, that have a high specific heat capacity and low density.

Get in touch

TR testing is an important tool for understanding the subsurface.

At SEP Geophysical, we have the experience and equipment to provide accurate and reliable measurements. Contact us today to learn more about our services.

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