What Are Dust Explosions?
Dust explosions are the fast combustion of dust particles in an enclosed location. The most common dust explosions occur in coal mines, though they occur in a variety of industries. A dust explosion will occur anywhere where powdered combustible material is present. In order to prevent dust explosions, it is important to first understand what causes them.
In order for a dust explosion to occur, there are certain conditions that need to be present.
- Combustible dust molecules must be suspended in the air
- The dust in the air must be confined to a certain space
- Some type of oxidant is present (in most cases, the atmospheric oxygen provides this)
- A source of ignition (spark, open flame)
The most common cases of dust explosions have occurred with coal, sawdust, and magnesium. Other materials that can cause dust explosions include grain, flour, and pollen. Powdered metals can also be a concern for dust explosions.
Preventing Dust Explosions
There are precautionary measures that can be set into place in order to avoid dust explosions. Ultimately, the industry and type of dust that is being created determines the alternatives and processes to make a space safer.
“Inerting” – This is the process of maintaining an inert gas, or gas that is not chemically reactive, like nitrogen, confined in a space to decrease the probability of a combustion explosion. By reducing one of the central elements necessary to cause a dust explosion (oxygen concentration or fuel concentration) the chances of a dust explosion occurring are significantly lessened.
Proper Housekeeping – Limiting the amount of dust in a confined space can help prevent excessive amount of build up and ultimately a dust explosion. Industries where vast amounts of dust are produced must follow specific guidelines OSHA has set in place, including:
- Workplace inspection and dust testing
- Proper cleaning and dust control programs
- The use of proper dust collection systems
- Cleaning methods that avoid the production of dust clouds
- Controlling open flames and sparks