IMG 6475

The minimum ignition energy is the lowest voltage spark that is capable of igniting a dust cloud at its most easily ignitable concentration in air. A capacitive generated spark is used in place of processing plant sparks such as propagating brush discharges, brushes and mechanical and electrical sparks.

Testing Principle and Methodology

A small quantity of the material to be tested is dispersed in a 1.2L glass tube pressurized with compressed air, and a spark of known energy is activated to attempt to ignite the material. The spark energy is decreased from typically 1000mJ to the lowest energy typically 1mJ or until the material does not ignite.

Different concentrations of the material are tested at the lowest spark energy to determine the MIE. ASTM recommends the particles size of the material to be tested to be at least 95% less than 75 microns and less than 5% moisture. In certain unique cases where there is no chance of segregation of the material during normal operation, the material can be tested as received. In case of uncertainty on how to perform the testing please contact Prime Process Safety Center for guidance. About 150g of the material is required to perform the MIE test. Once ignition is obtained at 1000mJ, the energy of the spark is decreased and the concentration of the dust varied until ignition does not occur to establish the MIE.


Typical Minimum Ignition Energy Graph


The MIE test is conducted in accordance with the American Standard Testing Method (ASTM) E2019. ‘’Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air’’

Data interpretation

The MIE is determined at the lowest possible voltage spark capable of igniting the material at its most ignitable concentration. Materials with MIE < 1000mJ are sensitive to ignition by electrostatic discharges, materials with MIE < 30mJ are very sensitive to ignition by electrostatic discharges and materials with MIE < 3mJ are extremely sensitive to ignition by electrostatic discharges. Materials with MIE > 1000mJ are considered to be not sensitive to ignition by electrostatic discharges.

When to perform (MIE)

MIE is performed when assessment of likelihood of ignition during powder handling is required and has specific application for the assessment and control of electrostatic hazards. Whenever the avoidance of Ignition Source is a basis of safety for the operation and handling of materials in a processing plant, the minimum ignition energy must be determined. The result is used to determine how sensitive the materials are to ignition sources such as electrostatic discharge and  mechanical sparks.

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 dust MIE test, ensuring accurate and reliable results.
  • We have state-of-the-art explosibility 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 Minimum Ignition Energy (MIE) in relation to combustible dust?

Answer: MIE represents the minimum amount of energy required to ignite a dust-air mixture, leading to combustion or an explosion. It’s a critical parameter in assessing the ignition hazards associated with combustible dust particles.

Why is knowing the Minimum Ignition Energy (MIE) of combustible dust important?

Answer: Understanding the MIE helps in assessing the potential ignition risks of combustible dust. It aids in risk assessment, hazard analysis, and implementing safety measures to prevent dust-related explosions.

How is the Minimum Ignition Energy (MIE) of combustible dust determined?

Answer: The MIE is determined through specialized testing methods that involve igniting a dust-air mixture with varying energy levels and observing the minimum energy required for ignition under controlled conditions.

What factors influence the Minimum Ignition Energy (MIE) of combustible dust?

Answer: Factors such as the type of dust, particle size distribution, moisture content, chemical composition, and specific characteristics of the dust particles significantly impact the MIE.

How is knowledge of the Minimum Ignition Energy (MIE) utilized in workplace safety?

Answer: Understanding the MIE aids in developing safety protocols, risk mitigation strategies, regulatory compliance, and implementing measures to prevent dust-related incidents in workplaces dealing with combustible dust.