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Our Solutions: Testing

Thermal Stability Testing & Analysis

Apparatus for thermal stability testing of chemical substances.

Our Thermal Stability Testing Laboratory provides critical data to assess the reactivity and stability of your chemicals under various thermal conditions, helping to prevent and mitigate chemical reaction hazards, explosions, and fires.

We conduct the following thermal stability tests to simulate thermal hazards, reaction risks, and assess heat sensitivity:

  • Air Over Layer Testing
  • Bulk Powder (Diffusion Cell) Testing
  • Aerated Cell Testing

Please contact us if you have specialized thermal stability testing needs, or if you require a full Chemical Reaction Hazards Testing (CRH) or other services related to chemical reactivity and safety.

Thermal stability testing

Why Thermal Stability Testing is Essential

Thermal Stability Testing is essential for industries dealing with thermally reactive substances. With thorough Thermal Stability Testing, you can:

  • Evaluate the heat sensitivity of materials to identify substances prone to thermal degradation, thermal runaway reactions, or other reactivity issues.
  • Assess thermal hazards by determining how materials respond to changes in temperature, including their potential for decomposition or violent reactions.
  • Determine safe processing conditions by identifying temperature thresholds at which materials become unstable, reactive, or pose safety risks.
  • Ensure regulatory compliance by performing regular thermal stability tests to meet safety standards, industry regulations, and risk management protocols.


By incorporating Thermal Stability Testing into your safety protocols, you can better manage thermal risks and protect both your workforce and the environment.

Discover Our Range of Thermal Stability Testing Services

Protecting your people, workplaces, business, and the environment from thermal stability hazards that could lead to fires, explosions, or other risks depends on the identification, mitigation, and management of thermal reactivity risks.

We provide a range of thermal stability testing services conducted in accordance with internationally recognized standards, ensuring accurate and reliable results. Our testing helps you identify and assess the potential thermal hazards of reactive materials, with a turnaround time of 7-10 business days from receipt of the sample.

Learn more about our testing services below and contact us for a free, no-obligation consultation today.

Air Over Layer

The air over layer test is conducted to establish the onset temperature of exothermic activity on thin layers of materials when exposed to elevated atmospheric temperatures. It replicates thin layer (up to 15 mm) deposits in a drying situation i.e. drier walls or roofs where hot air may rush over the surface.

Using a small tray test cell, a sample is placed inside a cell and thermocouples are placed into the material at three locations. This assembly is then placed into a digitally controlled horizontal laboratory tube oven with a controlled heated air supply.

Either of the below tests can be performed using a data acquisition system to monitor, detect and record any exothermic activity. 

An environmental temperature is digitally increased from ambient conditions up to 400°C at 0.5°C.min-1. This test configuration is used for estimating exothermic activity for onset temperature.

The loaded test cell is placed into a heated oven and set to a specified temperature for a duration of 24 hours. The temperature selected can be based on working or proposed process conditions, plus factors for safety. Alternatively, full determination can be undertaken, whereby several isothermal tests can be conducted to establish a definitive ignition temperature.

Not only is the air over layer test a necessity in evaluating whether current or proposed drying and process temperatures are safe, it can also confirm the possibility of using higher temperatures to increase productivity.

Bulk Powder (Diffusion Cell)

The bulk powder diffusion cell test is conducted to establish the onset temperature of the potential exothermic activity of a material when exposed to elevated atmospheric temperatures. It replicates small bulk deposits in any drying situation where air is naturally available.

Using an open cylindrical glass test cell with a sintered glass bottom and a sample is placed inside the cell. Thermocouples are then inserted through the wall into the material at four locations from the bottom upwards. This assembly is placed into a digitally controlled laboratory oven and either of the below tests are performed using a data acquisition system to monitor, detect and record any exothermic activity.

An environmental temperature is digitally increased from ambient conditions up to 400°C at 0.5°C.min-1. This test configuration is used for estimating exothermic activity for onset temperature.

The loaded test cell is placed into a heated oven and set to a specified temperature for a duration of 24 hours. The temperature selected can be based on working or proposed process conditions, plus factors for safety. Alternatively, full determination can be undertaken, whereby several isothermal tests can be conducted to establish a definitive ignition temperature.

Not only is the bulk powder diffusion cell test a necessity in evaluating whether current or proposed drying and process temperatures are safe, it can also confirm the possibility of using higher temperatures to increase productivity.

Aerated Cell

The aerated bulk powder diffusion cell test is conducted to establish the onset temperature of the exothermic activity of a material when exposed to elevated atmospheric temperatures. It replicates small bulk deposits in any drying situation where heated air is percolated through a material i.e. fluid bed driers.

Using a cylindrical glass test cell with a sintered glass bottom, the sample is placed inside the cell. Thermocouples are then inserted through its wall into the material at four locations from the bottom upwards. A glass lid is applied, and a regulated hot air supply that pushes air through the test material is connected. The assembly is placed into a digitally controlled laboratory oven and either of the below tests are performed using a data acquisition system to monitor, detect and record any exothermic activity.

An environmental temperature is digitally increased from ambient conditions up to 400°C at 0.5°C.min-1. This test configuration is used for estimating exothermic activity for onset temperature.

The loaded test cell is placed into a heated oven and set to a specified temperature for a duration of 24 hours. The temperature selected can be based on working or proposed process conditions, plus factors for safety. Alternatively, full determination can be undertaken, whereby several isothermal tests can be conducted to establish a definitive ignition temperature.

Not only is the aerated bulk powder diffusion cell test a necessity in evaluating whether current or proposed drying and process temperatures are safe, it can also confirm the possibility of using higher temperatures to increase productivity.

Can't find the thermal stability testing you need?

Get in touch with one of our experts to learn how our thermal stability testing services can help you prevent fires, explosions, and other thermal hazards.

From evaluating the heat sensitivity and reactivity of chemicals to assessing a material’s stability under varying temperatures, and from identifying potential thermal runaway reactions to evaluating the risks associated with hazardous thermal processes, we offer thermal stability testing solutions for any material, product, or chemical that may pose thermal hazards, including fire and explosion risks.

The Sigma-HSE Advantage

From exothermic effects to flashpoint testing, Sigma-HSE is your single solution provider for a range of thermal stability testing. Our dedicated team of experts are committed to helping you ensure and maintain compliance.

Request a Quote for Thermal Stability Testing

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How to test the thermal properties of your materials

Receive quick and accurate data in just a few simple steps

Contact us

Get in touch with one of our experts so we can learn more about your specific requirements. We’ll then generate and send you a customized quote.

Prepare & ship

Prepare your samples and ship them to one of our global laboratories.

Test, analyze & report

Once we’ve received your samples, we’ll begin testing and analyzing. We’ll then create and send you a custom in-depth report with actionable insights.

Post-Project Support

If you need support after receiving your report, our after-sales support team will be on hand to assist you with any questions you may have.

Understand the thermal properties
of your materials

Testing for the thermal properties of your facilities materials is an important
aspect of safety compliance. Learn more about how we can assist you today.

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