Volume Resistivity Test – Powders and Solid Materials

Electrical volume resistivity is the electrical resistance measured across opposite faces of a cube of solid material with side length 1m.  Volume resistivity is used to predict, indirectly, the low-frequency dielectric breakdown and dissipation factor properties of some materials. Volume resistivity determines how easily or difficultly electrical current passes through a material. Higher resistivity values indicate poor conductivity, while lower values signify better conductivity. Electrical volume resistivity is an intrinsic property of a substance, dependent on its composition, structure, and temperature. Insulators typically exhibit high volume resistivity, while conductors have low resistivity.

Testing Principle and Methodology

Two rectangular electrodes, each having a surface area A, and distance between the electrodes D, are used and the volume resistivity of the material is calculated using the formula:


P       is Resistivity in ohm meters (Ωm)

R       Resistance

A       is electrode surface area in square meters

D      is distance between electrodes or thickness of test material

To determine the volume resistivity; a direct current voltage is applied to one electrode and current is measured through the sample to obtain the resistance, R through the other electrode. By measuring the electrode surface area and distance between the electrodes or thickness of the material, the volume resistivity can be calculated. Alternatively, the electrical resistance can be measured directly by utilizing a megger-ohmmeter.  The test is typically performed under different humidity conditions. The sample is typically tested in its commercial form or as received. In case of uncertainty on how to perform the testing please contact Prime Process Safety Center for guidance.

Applicable Standard

The volume resistivity test is conducted in accordance with the American Standard Testing Method (ASTM) D257. ‘Standard Test Methods for DC Resistance or Conductance of Insulating Materials’,  BS 5958: Part 1: 1991 and BS 7506: Part 2: 1996, EN ISO/IEC 80079-20-2, and NFPA 77.


Volume Resistivity Test Cell manufactured by ANKO.

Data Interpretation

The volume resistivity (Ωm) of the material is classified as follows:

<105 Conductive / Low Resistivity
105 to 109 Static Dissipative / Medium Resistivity
>109 Non-Conductive / High Resistivity

By knowing the volume resistivity of your material, measures can be put in place to safely handle the material. This can be achieved by handling these materials in a well earthed environment (earthed conductive or static dissipative containers, silos, hoppers, and plant equipment). The build-up and retention of charge on a material or equipment possess the biggest threat if the charge is suddenly released in the form of a spark discharge, which can cause an ignition of a flammable atmosphere. Therefore, it is imperative to know and understand the electrostatic properties of your materials to ensure they are handled correctly to prevent discharges and potential ignition of flammable atmospheres.

When to perform Volume Resistivity

It is recommended to perform the Volume resistivity testing during handling of bulk materials in which electrostatic charging of the powder or solid material can occur. Typically, the higher the volume resistivity value, the more resistive or less conductive the material is. High resistivity or Low conductivity materials tend to accumulate and retain charges. Low resistivity materials or static dissipative materials tend to conduct or dissipate charges easily.

Why work with Prime Process Safety Center

  • Prime Process Safety Center is a leader in process safety testing with very experienced laboratory personnel. At Prime Process Safety Center our goal is to provide accurate, reliable and defensible data that meets industry and regulatory standards. We understand the need for the quality of your data, and we work assiduously to achieve just that.
  • We are knowledgeable and experienced in performing volume resistivity test, ensuring accurate and reliable results.
  • We have state-of-the-art volume resistivity testing equipment, providing precise and sensitive measurements.
  • We follow strict testing protocols and quality control measures to ensure consistent and reliable test results.
  • Our team can interpret and analyze the data obtained from the tests, providing valuable insights and recommendations for your specific application or research.


What is Electrical Volume Resistivity?

Answer: Electrical Volume Resistivity, often simply called volume resistivity, refers to the material’s inherent property that describes its ability to resist the flow of electrical current through its volume.

How is Electrical Volume Resistivity Measured?

Answer: Volume resistivity is measured by applying a known voltage across a sample of material and measuring the resulting current passing through it. The resistance and dimensions of the sample are used to calculate the resistivity.

Why is Electrical Volume Resistivity Important?

Answer: Volume resistivity of powders and solid materials is crucial in determining a material’s suitability for electrical insulation, as well as in assessing its ability to conduct or resist electrical currents in various applications.

What Factors Affect a Material's Volume Resistivity?

Answer: Factors influencing volume resistivity include material composition, purity, temperature, relative humidity, and crystalline structure.

What Materials Typically Have High Volume Resistivity?

Answer: Insulating materials like ceramics, glass, and certain plastics usually exhibit higher volume resistivity values, making them suitable for electrical insulation.

What are the Applications of Volume Resistivity Testing?

Answer: Volume resistivity testing is essential in selecting materials for electrical insulators, cables, semiconductor devices, and other electrical components.

How Does Temperature Affect Volume Resistivity?

Answer: In general, volume resistivity tends to decrease with increasing temperature due to increased thermal agitation and mobility of charge carriers.