Many manufacturing processes create very small particles of dust that may become airborne, where they settle on surfaces and in crevices throughout the plant. Eventually, these particles not only create a housekeeping issue, but if the particles are combustible, they can represent a potentially explosive dust cloud if disturbed.
It is essential for manufacturing factory managers to understand the risks of combustible dust and ensure they manage combustible dusts in their facilities. A well-designed, maintained, and operated dust collection system is an integral part of your effort to comply with this and other standards and regulations.
Donaldson can supply dust collectors to support your combustible dust control strategy by interfacing with you and your experts on fire and explosion protection equipment and solutions.
1. Know your standards and codes. Many standards and codes may influence your decisions on dust control, including local, state, and European regulations. Knowing the regulations that apply to your facility is critical, and you should always research the regulation requirements in your area. A few commonly referenced standards for combustible dust risk management strategies include those issued by: ATEX, VDI, DSEAR, CRAM, DIN, EN, and INERIS.
Since each authority having jurisdiction may have a specific set of codes it references, you may need to have general knowledge of more than one standard or code. Some of the most commonly referenced standards are published by the European Union, including both design and operational standards focused on combustible dust. Since these standards are often cited by authorities and have been adopted as code in many areas of Europe, they can be a good starting point for consideration in developing your combustible dust management strategy:
Industry and Application Specific Standards (1999/92/EC)
Design Standards (2014/34/EU)
2. Assess your dust and process. Determine whether your dust is combustible. Testing an actual sample of dust with a qualified lab will give you the most reliable information. If a simple “go/no-go” evaluation proves it's combustible, further tests can determine if it’s explosible (can ignite in a cloud), how fast that explosion can happen, and how much force it can carry. This information could impact the type of mitigation equipment needed to mitigate the hazard. Next, audit your process to identify where nuisance dusts are generated, released, or tend to accumulate. These are often intake and mixing locations, bag dumps, and welding or cutting stations. In each location, analyze the production processes, housekeeping practices, dust control measures, and potential ignition sources present.
3. Understand fire triangle, explosion pentagon. Fire management strategies traditionally focus on the control or elimination of one of the three key elements necessary for a fire (oxygen, heat, and fuel)—often represented by the “fire triangle.” Managing one or more of the elements in the triangle can decrease the fire risk.
Explosion risk management strategies consider a slightly expanded set of elements often represented as an “explosion pentagon.” In addition to the key elements from the fire triangle, the explosion pentagon includes two additional elements necessary for an explosion: “Dispersion of Dust” and “Confinement of Dust.”
While many explosion management strategies focus on controlling the same elements in the fire triangle, explosion risk management strategies that focus on the dispersion of dust, or the containment of dust alone, may require a separate strategy to address any remaining fire risks
4. Develop a mitigation plan. Once you have determined the combustibility of your dust, you can develop a plan to mitigate the risks in your process. First, identify ways to limit dust accumulations—however, housekeeping is only a partial solution. Also, consider the design of your dust collection system; for example, the physical location of the dust collector—outdoors versus indoors—will depend on the process hazards and risk assessment. Additionally, consider adding mitigation devices to your system, such as ignition controls or explosion vents. A wide range of fire and explosion mitigation equipment is available. Solutions focus on reducing the likelihood of an incident (prevention) and/or reducing the severity of an incident (protection). Selection should be based on the risks associated with the process. You can learn more about these in the interactive graphic below.
Donaldson can help review your mitigation strategies and integrate Donaldson equipment into your dust management strategy.
It’s essential to have a comprehensive plan to manage and mitigate potential combustible dust risk. Learn more about prevention strategies that focus on ways to reduce the potential for a combustion event to occur in a dust collector.
Dr. Chris Cloney from Dust Safety Science recently interviewed Chrissy Klocker, Applications Engineering Manager at Donaldson, for his popular podcast series. The episode, called "Five Misconceptions About Collecting Combustible Dust," covers five areas of combustible dust collection that seem to generate a lot of confusion for process owners.