IMG 6501

The Minimum Autoignition Temperature (MAIT) of a dust cloud stands as a pivotal parameter in assessing the propensity for spontaneous combustion within environments where airborne combustible dust particles are prevalent. This temperature represents the lowest threshold at which a dust-air mixture, suspended in the atmosphere, can ignite spontaneously without the need for an external ignition source. The test is used to assess the maximum operating temperature for electrical and non-electrical equipment used in areas where test material is present.


A small quantity of the material to be tested is dispersed under defined air pressure in a Godbert Greenwald Furnace that is preheated to a defined temperature. At the ignition of the material, the temperature of the furnace is reduced until there is no ignition at which point the concentration of the material and the pressure of dispersion are varied until the non-ignition is independent of the sample concentration and air pressure. 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 50-100g worth of material is typically required to perform this test. The test typically begins at an oven temperature of 500 degrees Celsius and once ignition is observed the temperature of the oven is reduced in steps of 20 degrees Celsius until ignition is not observed. At the oven temperature where ignition is not observed, the concentration of the material as well as the air pressure is varied to obtain at least 10 non-ignitions to establish the MAIT value.


Typical Minimum Autoignition Temperature (MAIT) Data

Applicable Standard

The MAIT test is conducted in accordance with the American Standard Testing Method (ASTM) E1491. ‘Standard Test Method for Minimum Autoignition Temperature of Dust Clouds’’

Data Interpretation

Materials with MAIT values between 400ᣞC and 500ᣞC are common for most organic solids and some metal powders. Other organic solids such sulfur powder may be very sensitive to hot surface temperature and can have MAIT values of less than 250ᣞC. Factors such as the composition, particle size, moisture content, and specific characteristics of the dust significantly influence this critical ignition temperature. Industries handling combustible dust rely on the knowledge of the MAIT values to design operational controls, select appropriate equipment, and establish safe temperature thresholds to minimize the risk of spontaneous ignition and prevent fire hazards associated with combustible dust clouds.

When to perform (MAIT)

MAIT is performed when the assessment of the likelihood of ignition during powder handling is required and have specific application for the assessment and control of hot surface ignition.

The results obtained from the Minimum Autoignition Temperature test are used to assess the susceptibility of a dust cloud to ignition by heated environments, such as hot surfaces and grinding sparks.  It is also used in the selection of suitable electrical equipment for Class II locations.

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 MAIT 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 Autoignition Temperature (MAIT) of Dust Clouds?

Answer: MAIT refers to the lowest temperature at which a dust cloud can ignite spontaneously in the air without an external ignition source, leading to combustion.

How is MAIT Determined for Dust Clouds?

Answer: MAIT is determined experimentally by subjecting a dust cloud to various temperatures in a controlled environment and identifying the lowest temperature at which self-ignition occurs.

Why is MAIT Important in Industrial Settings?

Answer: Understanding MAIT is crucial for assessing the fire and explosion risks associated with handling combustible dusts. It helps in implementing preventive measures and safety protocols to avoid dust cloud ignition.

What Factors Influence the MAIT of Dust Clouds?

Answer: Several factors affect MAIT, including the particle size distribution, dust concentration in the air, moisture content, chemical composition, and the specific conditions under which the dust is dispersed.

How is MAIT Used in Industrial Safety Practices?

Answer: MAIT data is used in hazard assessments, process design, and safety measures within industries handling combustible dusts. It assists in establishing safe operating conditions, ventilation systems, and explosion prevention strategies.