Is My Dust Combustible? What to Know About Combustible Dust

combustible dust

Few people think about dust as something that may be combustible. But many manufacturing processes and industrial applications generate dust that may be combustible. As a result, combustible dust is a significant safety hazard across many industries, from food production to pharmaceuticals. 

What is Combustible Dust?

Combustible dust refers to any material consisting of distinct particles that may catch fire or explode when mixed with air. It’s defined as ‘a finely divided combustible particulate solid that presents a flash fire hazard or explosion hazard when suspended in air or the process-specific oxidizing medium over a range of concentrations.’

In rare instances, you may not even need an ignition source to start combustible dust fires or explosions. Many manufacturing processes can generate combustible dust when working with materials, such as:

  • Handling
  • Conveying
  • Dividing 
  • Crushing
  • Drying 
  • Compacting
  • Grinding
  • Pulverizing
  • Sanding
  • Sawing
  • Screening 
  • Transporting

While many processes may produce combustible dusts, you may be surprised by the materials that can create combustible dust. Coal, lignite, metals, and peat are obvious sources, such as soy flour, cornmeal, and coffee dust. OSHA has published a list of materials that may create combustible dust during the manufacturing process. 

Since dust is so minuscule, it’s easy to underestimate the combustible dust hazards. For example, a single combustible dust explosion in Georgia in 2008 resulted in 14 deaths and 38 injuries. This catastrophic event occurred at a sugar refinery, highlighting the dangers of combustible dust created from ordinary materials. 

Generally speaking, five factors must be present to result in a dust explosion. These include:

  • Combustible dust
  • Oxygen in the surrounding environment
  • Confinement of a dust cloud
  • An ignition source. 
  • Dispersion of the dust particles

If you remove or control these elements, you can prevent a dust explosion. 

Is My Dust Combustible? 

Aside from the different combustible and chemical dusts listed by OSHA, there may be other combustible dusts. To know whether a dust is combustible, you need a dust type test. Multiple reputable companies can test a dust sample from your facility. This test will evaluate the dust and calculate critical variables that determine whether it is combustible. 

If you think there is a risk of combustible dust at your facility or you have confirmed its presence, there are several standards that you should be familiar with, including:

  • NFPA 652 Standards on the Fundamentals of Combustible Dust: This standard requires companies to complete a dust hazard analysis for new and existing processes and facilities. It also contains instructions for all facilities that may generate combustible dust.
  • NFPA 654 Standard for the Prevention of Fire and Dust Explosions from the Manufacturing, Processing, and Handling of Combustible Particulate Solids: This standard defines combustible dust. Combustible particulate solids are defined as ‘any solid material composed of distinct particles or pieces, regardless of size, shape, or chemical composition that present a fire hazard.  
  • NFPA 61 Standard for the Prevention of Fire and Dust Explosions in Agricultural and Food Processing Facilities
  • NFPA 664 Standard for the Prevention of Fires and Explosions in Agricultural and Food Processing Facilities
  • NFPA 484 Standard for Combustible Metals
  • NFPA 655 Standard for the Prevention of Sulfur Fires and Explosions

How Can I Minimize the Risks from Combustible Dust?

OSHA has released guidelines to help employers understand policies to prevent dust fires and explosions. These policies include the following actions

  • Inspect and test for combustible dust.
  • Implement cleaning and control measures to prevent dust collection or the formation of dust clouds.
  • Use explosion-proof vacuum systems.
  • Use appropriate dust collection systems and filters.
  • Recognize dust that may escape from process equipment or ventilation systems and eliminate it. 
  • Reduce the number of surfaces that may collect dust and require cleaning.
  • Inspect for dust residue in both open and hidden areas. 
  • Provide access to hidden spaces to make inspections easier.
  • Do not place relief valves near dust deposits. 

Vacuum systems are often the best way to deal with combustible dust. You do not want to use push brooms, air compressors, or fans to create dust clouds. These tools do not eliminate the dust; they only move it around. 

Combustible dust is a very dangerous material. A dust explosion or fire can result in injury or death. If you believe your dust may be combustible, it’s crucial to verify this through a valid test. If found combustible, you must implement the proper precautions to keep your employees and property safe.

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