As a featured speaker at Dustiness Day 2024, Michel Vandeweyer will shed light on the complexities of dust explosions, unraveling their core principles, demonstrating the phenomenon live, and sharing lessons from a compelling case study. His combination of deep theoretical knowledge and practical experience—as a production supervisor and head of internal fire safety—positions him as an authoritative figure on ATEX regulations and industrial safety.
In this conversation, we’ll dive into the science behind dust explosions, the necessity of strict safety protocols, and the vital role of complying with ATEX directives. Michel will also offer a preview of his upcoming presentation, outlining key takeaways for professionals dealing with dust hazards.
Michel, you have an extensive background as an industrial engineer in chemistry and extensive experience in process chemistry and chemical logistics.
Q: How did your roles at BASF and Lawter shape your understanding of dust explosion risks?
A: Working at BASF and Lawter developed my understanding of the potential dangers associated with combustible dust and flammable gases. At Lawter, I oversaw daily operations in chemical installations as a production supervisor and recognized how industrial processes can generate hazardous dust clouds, even when the primary products seem relatively harmless. These environments must constantly balance efficiency and safety, but underestimating the risk is easy. A subtle shift in operations, like changing the type of material used in production or increasing throughput, can inadvertently create an explosive environment. Heading the internal fire department sharpened my focus on fire and explosion prevention. Training sessions showed me how quickly a fire could escalate into a dust explosion—and how challenging it was to control. The experience left a lasting impression. It wasn’t just about compliance; it was about engineering processes to inherently reduce the potential for dust accumulation and ignition.
Q: What exactly is a dust explosion, and why is it so dangerous?
A: A dust explosion is a rapid combustion event triggered when fine particulate matter becomes suspended in the air and meets an ignition source. It’s a highly volatile situation, and the conditions needed for an explosion are often present without people realizing it: All too often, thick layers of dust are hidden on support beams, and flexible connections that may fail, and the insides of installations are often covered with layers of dust, even if the transported product is coarse. The danger lies in the fact that most dust particles are combustible, and in industries like chemical processing, food production, or pharmaceuticals, fine powders are everywhere.
The explosion hazard comes not just from the initial event but from secondary explosions. In many industrial accidents, the first explosion disturbs settled dust layers on beams, ledges, or equipment. This newly airborne dust then ignites, creating a much larger, more destructive explosion. Secondary explosions can rip through entire facilities, demolishing structures and severely injuring or killing workers. That’s why dust explosions are so devastating—they evolve rapidly, often with no time to react between the first and subsequent explosions.
Q: What are the key factors that contribute to dust explosions?
A: Dust explosions are driven by five simultaneously occurring phenomena, which form what we call the “dust explosion pentagon”:
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Fuel (combustible dust):
Dust particles from organic materials like flour, sugar, and wood, or metals like aluminum and magnesium, can all serve as fuel. Even substances that aren’t typically flammable, such as plastics, can ignite if they are in fine particulate form.
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Oxygen (oxidizer):
(Atmospheric) oxygen is required to fuel a dust explosion. Even in environments with reduced oxygen levels (typically above 10%vol), a dust cloud can still ignite, though the explosion might be less severe.
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Ignition source:
Ignition sources in industrial settings are often varied and numerous. They can range from mechanical sources, like friction or impact sparks from equipment, to electrical discharges, static electricity, or even hot surfaces. Even something seemingly benign, like a motor overheating or welding operations nearby, can ignite most dust clouds or create a smouldering fire upon landing in a dust layer.
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Dispersion (suspension of dust):
The dust needs to be suspended in the air. Many dust explosions occur because dust accumulates in hard-to-reach places like rafters or ducts, and once disturbed, it becomes airborne. For example, compressed air used for cleaning can disperse settled dust into a combustible cloud, increasing the likelihood of an explosion.
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Confinement:
Explosions can be especially dangerous when they occur in confined spaces. Dust explosions inside silos, mills, or dedusting systems, for instance, can generate significant overpressure, leading to structural failures or catastrophic ruptures. The confined space allows pressure to build up rapidly, amplifying the destructive force of the explosion.
Q: How do you approach training for safety professionals on dust explosion preparedness?
A: The core of our training is understanding and eliminating the root causes of dust explosions before they can happen once the explosion starts, there’s little anyone can do to stop it. The key is prevention through proper design, maintenance, and operational protocols.
We focus on educating professionals about:
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Understanding material properties:
Not all dust behaves the same way. Professionals need to know the explosiveness of the materials they work with. The explosion characteristics taught in our training are geared towards teaching our students where and how to obtain the relevant value information, like MIE, MIT, and other critical parameters for their specific types of dust, and how to interpret them.
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Housekeeping and maintenance:
Explosion risks can be substantially reduced by simply keeping the work environment clean. Dust build-up on horizontal surfaces, especially in hidden or hard-to-reach areas, is a major hazard. In our training, we show how to identify and mitigate these hidden dust accumulation risks, for example, by using soft vacuums instead of compressed air when cleaning, but also by showing how to make an installation more dust-tight.
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Zoning and how to work safely in a zoned area:
To correctly asses an explosion risk, one must start by assessing the possibility of an explosive mixture. The possibility of an explosive dust cloud is higher inside of a dedusting filter, in comparison with the normal working environment, and therefore requires different measures and degrees of safety. There are a lot of misconceptions about how to work safely in a zoned area, and how to act accordingly.
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Emergency protocols:
We also train professionals on how to handle dust-related emergencies safely. For instance, using water to extinguish a dust fire must be done with caution, as high-pressure water can disturb dust layers and create dangerous dust clouds. Instead, a wide-spray water curtain is more effective.
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ATEX compliance:
ATEX directives are also covered in our training. Many professionals think that once their equipment is ATEX-certified, their plant is safe. But equipment is just one part of the solution. Ensuring the entire process—from material handling to dedusting—is correctly implemented, is vital. We help industries set up proper zoning , and correctly assess the explosion risks, including adequate isolation barriers.
Q: The ATEX directives are central to managing dust explosion risks. What should industries focus on for compliance?
A: Many misunderstand or only partially implement ATEX compliance. ATEX includes two essential directives:
ATEX 114 (Directive 2014/34/EU): This directive addresses equipment and safety measures used in potentially explosive atmospheres. Equipment manufacturers must ensure their products are designed to minimize ignition risks and meet the latest safety standards.
ATEX 153 (Directive 1999/92/EC): This directive focuses on the health and safety of workers in explosive environments. Employers must conduct risk assessments, train workers, and implement safety measures.
Industries must focus on:
Zoning: Proper zoning defines areas at risk of forming explosive dust clouds and classifies them accordingly. Both dust clouds and dust layers must be considered, as a dust layer can form a dust cloud. However, zones should remain as small as possible. Optimizing zoning reduces the number of ATEX-compliant equipment needed, lowers costs, simplifies compliance, and most importantly, directly impacts explosion risk.
Ignition control: Equipment must be properly grounded to prevent spark discharges, and tools used in hazardous zones must be appropriate for these atmospheres. But ignition control isn’t just about equipment—personnel must also be aware of how they can create ignition risks through clothing or by failing to follow procedures.
Explosion Protection Document (EPD): This document is essential for compliance. It records explosion risks at a facility, safety measures in place, and how often those measures are reviewed and updated. It includes data from dust explosion tests, detailed zoning plans, and an inventory of all ignition sources within explosive atmospheres. The EPD also covers training programs, emergency procedures, safety philosophies, and more. In short, the EPD is a comprehensive tool for managing explosion risks.
Q: What are some common misconceptions about ATEX safety measures?
A: One common misconception is the belief that if the dust layer is thin or only present intermittently, it doesn’t pose a threat. But even a thin layer of dust, when disturbed, can create a large enough cloud to ignite and cause an explosion. Another misconception is that “if it hasn’t happened yet, it won’t happen.” Many facilities operate for years without an incident, leading workers to become complacent, but this is a dangerous mindset. Dust explosions often occur after years of neglect or minor process changes that unintentionally increase the risk.
Another misunderstanding is that a zone is only present from time to time: “we only have a zone during certain periods or certain actions”. The zone class already takes this into account, but once defined, is always present. The explosive mixture, however, is not always present. To (temporarily) eliminate a zone, one must know very well what is the exact origin of the zone, and take away ALL reasons of the zone.
Q: What challenges do dynamic environments pose for controlling dust hazards?
A: One of the biggest challenges in dynamic environments is the constant change in material properties, production processes, and operational parameters. When a company switches from handling one type of powder to another, or when they scale up production, they often fail to re-evaluate the explosion risks. Even small changes, like increasing production rates or modifying equipment, can significantly increase the likelihood of a dust explosion.
For example, a minor change in the type of product being handled might seem insignificant but could introduce new risks. As an example: if the new product has a higher Kst value, the foreseen explosion protection systems might become under-dimensioned and no longer sufficient A decrease in MIE, which could also be the consequence of an increase in process temperature, could result in ignition sources becoming incandescent which where harmless before the change. If the facility’s explosion protection philosophies and risk analyses aren’t updated to account for this, the consequences can be catastrophic.
Q: How important is hands-on experience for professionals dealing with dust explosion risks?
A: It’s invaluable. There’s a huge difference between reading about explosion risks and seeing them firsthand. When professionals experience a controlled explosion, they quickly grasp just how dangerous dust can be. They leave our sessions with a greater respect for dust hazards and are likelier to follow safety protocols. Hands-on training also instills confidence. When you know what to expect and how to respond, you’re better equipped to prevent accidents.
Q: What do you hope attendees of DUSTINESS DAY 2024 will learn from your live demonstration of dust explosion principles?
A: The live demonstration will showcase just how quickly a dust explosion can escalate. Most people think explosions are loud and obvious, but in reality, a dust explosion can develop silently, with minimal warning. By witnessing the process from dust suspension to ignition and explosion, attendees will gain a better understanding of the risks involved. It is also just a fun thing to do.
Q: Is there anything else you’d like our readers to know?
A: Yes, I would strongly recommend that anyone involved in industries where combustible dust is present take the time to listen to our recent podcast episode on the Dust Safety Science Podcast with Dr. Chris Cloney. It provides further case studies and insights into dust explosion prevention, and it’s a great resource for learning about the latest safety strategies.
Thank you for taking the time to sit down with us and to share your experience with our audience.
You’re welcome.
In Conclusion
Industries are evolving, and they must not overlook the risks of dust explosions. Michel Vandeweyer emphasizes the importance of strict safety protocols, hands-on training, and constant vigilance. In his upcoming presentation at Dustiness Day 2024, he will provide practical solutions and insights that ensure attendees know how to safeguard their teams and facilities.
Dust explosions are preventable with the right knowledge and action. Michel’s talk will equip participants with the tools to tackle these risks head-on.
