Hazards of Combustible Dust
Written By: Atanu Das on Tuesday, October 29, 2024
Combustible Dust: A Hidden Danger in the Workplace
Understanding Combustible Dust
Combustible dust is any material that can burn rapidly when in a finely divided form. Even materials that don't typically burn in larger pieces, such as aluminum or iron, can become explosible in dust form. Common examples include flour, sugar, and corn starch, which many workers might not recognize as potential hazards.
How Combustible Dust Forms
Combustible dusts can form in a wide range of industries and industrial processes, including agriculture, food production, textiles, chemical manufacturing, recycling facilities, woodworking operations, and metal works. These dusts are created when materials are transported, handled, processed, polished, ground, and shaped. Even a small amount of dust buildup on surfaces like rafters, roofs, ceilings, ducts, and windowsills can lead to a serious incident.
Causes of Combustible Dust Incidents
For a combustible dust incident to occur, several elements need to be present:
1. Fuel (the dust itself)
2. Oxygen
3. An ignition source (e.g., a spark from static electricity)
4. Dust particles suspended in the air at the right concentration
5. Confinement of the dust cloud in an enclosed or limited space
Secondary Explosions: A Major Threat
Secondary explosions are a significant concern in combustible dust incidents. An initial explosion can dislodge more accumulated dust into the air or damage containment systems, leading to a secondary explosion that is often far more destructive than the primary one.
Assessing and Controlling the Hazards
To mitigate the risks associated with combustible dust, employers should:
1. Conduct thorough hazard assessments
2. Use Safety Data Sheets and laboratory tests to determine dust explosibility
3. Perform dust hazard analyses with the help of subject matter experts
4. Implement dust containment measures, including dust collection systems and proper housekeeping methods
5. Use appropriate surfaces that minimize dust accumulation and facilitate cleaning
6. Regularly inspect for dust residues in open and hidden areas
7. Employ proper cleaning methods that don't generate dust clouds
8. Control ignition sources, including static electricity and open flames
9. Implement explosion protection methods such as deflagration venting or suppression
Regulatory Landscape
While OSHA doesn't have a specific standard on combustible dust, provisions in its general industry standards address certain aspects of combustible dust hazards. The agency also launched a National Emphasis Program on combustible dust in 2007, which was revised in January 2023
The National Fire Protection Association is currently consolidating six of its combustible dust-related standards into a single standard, NFPA 660, which could be issued as early as December 2024
By understanding the risks associated with combustible dust and implementing proper safety measures, employers can significantly reduce the likelihood of these potentially catastrophic incidents. Regular training, thorough inspections, and adherence to safety protocols are crucial in maintaining a safe work environment in industries where combustible dust is a concern