Electrical contractor putting on an FR jacket on the way to work.


Identifying and Reducing the Impacts of Combustible Dust Hazards

23 Dec 2019

Combustible dust is a significant concern across various industries and with good reason. Combustible dust incidents can lead to serious property damage and cause life-threatening injuries. Analyzing your work environment and enacting preventative measures, such as robust housekeeping and engineering control protocols, can make all the difference. Even with these safety precautions in place, incorporating FR/AR PPE as the final layer of defense can help mitigate the risk of injuries should the worst happen.

When a dust combustion occurs, any of the following events can occur: explosion, deflagration, and flash fire.

  • An explosion is a deflagration under pressure. It needs oxygen, fuel (in this case, dust), a thermal ignition source, a dispersion of fuel, and confinement. These five components lead to pressure buildup in process equipment and cause an explosion, which then can agitate fuel throughout the facility and trigger subsequent deflagrations or flash fires.
  • A deflagration has the above requirements except confinement and does not have the excessive damaging pressure associated with explosions.
  • A flash fire is a short-duration, rapidly moving flame front that spreads through a diffuse fuel, such as a dust, with no damaging pressure.

Dusts that are combustible or explosive require additional testing to support a Dust Hazard Analysis (DHA). The DHA provides vital information on lowering the risk of a dust combustion event and how to protect against it. Numerous tests are used to determine various dust characteristics and include the KST which is the deflagration index—or explosive power—of a dust. Even if a dust’s KST value is low, there is still a risk of explosion and subsequent fire threats. According to the 2019 edition of NFPA 652, Fundamentals of Combustible Dust, a DHA shall be performed for all new processes and existing facilities by September 7, 2020 and reviewed and updated every five years by a qualified individual.

Any combustible dust-related incident can not only damage property but also cause serious burn injuries if employees are not adequately protected. Implementing a robust FR/AR PPE program that works in tandem with combustible dust protocols help create a well-rounded mitigation program that clearly accounts for these risks.

Consider the following best practices to ensure your combustible dust hazard mitigation program comprehensively addresses your worksite’s needs:

  • Verify the KST value and other key test characteristics of all dusts and perform a DHA to help determine the necessary risk controls to protect against dust hazards.
  • Employ the hierarchy of risk controls to implement a program that helps reduce the likelihood of a dust combustion and use FR/AR daily wear as the final layer of defense to mitigate the severity of burn injury from potential deflagrations and flash fires.
  • Review NFPA 2112, the standard on flame-resistant clothing, to guide your FR/AR PPE selection.

Fully understanding potential impacts of combustible dust hazards in the workplace can help guide safety managers in their efforts to protect against them and foster a safe work environment for employees.

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