Dust Explosion Mitigation and Prevention
In order to understand dust explosion mitigation and prevention, you must understand what combustible dust is. A combustible dust is a finely divided combustible particulate solid that presents a flash fire or explosion hazard when suspended in air. Particle Size and Moisture Content play a pivotal factor in explosibility and ignition potential. Materials considered to be a combustible dust can be found in a variety of industries and can arise from handling everyday materials such as sugar, plastics, and sawdust.
Dust Explosions occur when all five of the legs of the Dust Explosion Pentagon are present.
- Fuel – Combustible Dusts serve as fuel for combustion. Examples include grain dust, plastics, cornstarch, coal, wood dust, and
- Oxygen – Air is the most common oxidizing medium. O2 must be present in sufficient concentration to support the combustion.
- Dispersion – A suspended cloud of explosive dust with sufficient concentration will allow combustion to occur more rapidly than in a layer.
- Confinement – A suspended dust cloud must be enclosed in order to build pressure that is characteristic of a dust explosion. Without confinement, the rapid combustion is a Flash Fire.
- Ignition – Ignition source is often the only leg of the pentagon not readily present. Possible ignition sources include open flame, hot surfaces, static or electrical discharges, and heat from friction or mechanical impact.
Dust Explosion Mitigation Techniques
NFPA 652, Standard on the Fundamentals of Combustible Dust (2019), requires that facilities and processes are designed to mitigate the dangerous consequences of fires and explosions that are a hazard of handling combustible dust. To meet this . requirement, facilities can elect to utilize either a Prescriptive approach or a Performance-Based approach.