Combustible Dust Reduction

While dust may appear benign, recent headlines prove otherwise. For example, a 2008 sugar dust explosion at a refinery in Georgia resulted in 14 worker deaths, 36 injuries and the near-destruction of the facility’s packing buildings. The loss is estimated at $275 million.

After a number of recent tragedies, safety professionals and regulators are devoting careful attention to the explosion and fire risks associated with combustible dust.

According to the U.S. Chemical Safety Board, the Georgia incident was the result of sugar accumulation within a confined, unventilated conveyor belt. An explosion, likely caused by an overheated bearing, traveled to nearby packing buildings and triggered secondary explosions fueled by sugar dust accumulations and spills near equipment and production floors.

Understanding the Risk

Several solid substances can create explosions if they become airborne in the form of a fine dust. Organic materials such as grain, sugar, sawdust or coal can combust, as can substances such as plastics, foam, chemicals, aluminum, magnesium and others.

Understanding the properties of the materials used in your facility’s production line is a critical step in reducing the potential for combustion. The Material Safety Data Sheet (MSDA), for instance, will provide important information.

It’s also important to realize that, depending on the substance, it can take very little dust to trigger an explosion. A layer of less than one millimeter can create a hazard, so if you can trace your name with your finger in dust, you need to correct that situation immediately.

Housekeeping Is Critical

The most important and effective way to address this exposure is preventing the accumulation of dust in the workplace. Dust should be contained and removed, and effective housekeeping is required to prevent dust from accumulating and reaching combustible levels.

While it is critical to contain combustible dust on the production floor, it is also important to routinely clean surfaces such as air ducts, overhead beams, light fixtures and the areas above false ceilings. Accumulated dust in easily overlooked areas can fuel combustion in areas that otherwise appear clean.

For example, six workers were killed in a 2003 explosion at a North Carolina pharmaceutical plant that investigators attributed to the accumulation of dust above a drop ceiling.

It is also important to pay attention to how housekeeping is performed. Instead of spraying dust off industrial equipment with compressed air, workers should vacuum the dust and dispose of it properly.

A Kentucky manufacturer of automotive acoustic insulation experienced an explosion when routine cleaning of equipment generated a combustible dust cloud that reached a malfunctioning production line oven.

Production equipment used for grinding, machining or sanding should also be equipped with hoods and vacuum equipment connected with a dust collection system. The dust collection equipment should also be inspected and cleaned on a regular basis.

Similarly, proper and routine equipment maintenance can help reduce the risk of overheating and other potential ignition sources. Companies should also make sure production and storage equipment is grounded to prevent static electricity.

Workplace design can also play an important role in reducing the combustible dust hazard. Fire suppression systems and equipment can be critical, as can the use of explosion vents in rooms, buildings and storage facilities to help dissipate energy from any explosions that may occur.

By taking protective measures, and increasing awareness among workers about the potential dangers, companies can reduce much of the risk presented by the accumulation of potentially combustible dust.

To learn more:

Next: Hazardous Materials Handling