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Combustible Dust Hazards

Combustible dust is any material capable of igniting when released into the air. Many factories and facilities process materials that are not considered explosive or flammable could include combustible dust hazards. During the processing or transportation of these otherwise benign materials, dust is released and accumulates. These particles or dust can be ignited by a spark (including static electricity) or fire anywhere in the facility resulting in a dust explosion.

Combustible dust explosions are a constant hazard in certain factories, coal mines, and grain processing facilities. The explosions can cause enormous overpressures inside structures, causing major structural damages and dangerous flying debris. Many people have been fatally injured in combustible dust explosions.

Common Types of Combustible Dust Hazards are:

 

  • Sugar Dust
  • Malt Dust
  • Wood Dust
  • Grain Dust

 

 

  • Metal Dust
  • Iron Dust
  • Coal Dust
  • Grain Dust

 

Primary dust explosions can cause secondary dust explosions. The primary dust explosion disturbs accumulated dust that is launched into the air. This released dust is ignited in a second explosion, which can be more dangerous than the initial, primary explosion.

Sugar

Sugar dust is created during the commercial refining and processing of sugar beets. There are numerous examples of workplace injuries resulting from the buildup of this dust. One of the worst industrial accidents in United States history was a sugar refinery explosion in Georgia in 2008. This combustible dust explosion was triggered underneath a sugar storage silo and resulted in the deaths of 14 people as well as 40 people injured. A Hazard Review incorporating combustible dust should be performed at any sugar processing facility to qualify the hazards and determine required mitigation strategies.

Malt

Malt (fermented grain), because of its fine particle size and organic composition has combustible dust properties including flash fire and explosion hazards. In a laboratory, malt will ignite and propagate combustion when dispersed over a spark igniter. A Hazard Review incorporating combustible dust should be performed at any facility utilizing malt to qualify the hazards and determine required mitigation strategies. Some simple strategies could include process revisions and a stepped-up housekeeping program to eliminate accumulated dust. Ino-Tek can offer more information.

Wood Dust

Wood dust is created during wood milling resulting in several wood dust explosions at wood mills across the country. A Hazard Review incorporating combustible dust should be performed at any facility creating explosive dust to qualify the hazards and determine required mitigation strategies. There are several steps, which should be taken by any facility milling wood and creating wood dust with a small particle size to insure that this material does not ignite. These steps should be formalized in a written dust safety plan and combined with a dust-monitoring system that can monitor the dust concentration in the air. Ino-Tek has designed and installed systems for this application.

Grain Dusts

Combustible dust explosions in Grain Storage Facilities have killed many people across the country. In 1976 alone, there were 16 major grain elevator explosions in the United States resulting in 19 deaths and 82 injuries in just one year. Nine people died and thirty-two were injured in one single grain elevator explosion in Texas. A Hazard Review incorporating combustible dust should be performed at any facility grinding grain to qualify the hazards and determine required mitigation strategies. This includes distilleries, bakeries, and other baking and processing facilities. These steps should be formalized in a written dust safety plan that includes provisions for housekeeping requirements to minimize the accumulation of dust.

Metal Dusts

Surprisingly to many people, metal dusts are flammable under certain conditions. One example of a flammable metal dust is aluminum. In 2003 a series of explosions were triggered at an aluminum manufacturing plant in Huntington Indiana. One step in the process of manufacturing aluminum wheels was grinding each wheel, which produced aluminum dust. Two workers were severely burned and one later died of his injuries. A Hazard Review incorporating combustible dust should be performed at any facility creating metal dust to qualify the hazards and determine required mitigation strategies.

Iron Dust

Iron dust is combustible and many accidents have been documented. The Chemical Safety Board has documented three separate combustible iron dust accidents at a single facility and determining the root cause of each to be combustible dust. A Hazard Review incorporating combustible dust should be performed at any facility creating explosive metal dust to qualify the hazards and determine required mitigation strategies. The need for adequate process design and careful housekeeping measures is critical. Ino-Tek can assist facilities in the development of these designs and procedures.

Coal Dust

Coal dust is one byproduct of mining for coal and is one of the causes of underground coal mine explosions. There are also fire and explosion risks from coal as it is transported to and utilized at power plants. There are proven methods for controlling explosion risks from coal including engineering design considerations, housekeeping procedures, and maintenance procedures. A dust hazard review is the first step in the design of these types of system. From this hazard review, a detailed safety plan should be developed. Ino-Tek has designed and installed systems to mitigate these dangers.

Resins

The manufacture of many plastic products involves the use of phenolic resins. The dust from these phenolic resins can be explosive when released into the atmosphere and exposed to an ignition source. In 2003, an explosion fueled by resin dust at a fiberglass manufacturing plant in Kentucky resulted in the deaths of 7 workers. A Hazard Review incorporating combustible dust should be performed at any facility utilizing resins to qualify the hazards and determine required mitigation strategies.

Plastics

Specialty plastics production can create polymer dust that meets the criteria of a combustible dust. A Hazard Review incorporating combustible dust should be performed at any facility utilizing polymers to qualify the hazards and determine required mitigation strategies. A dust hazard review is the first step in the design of these types of system and the hazard review must consider the explosive characteristics of the dust. Some specialized products require actual dust testing to determine these properties. There are dust-monitoring systems that can monitor the dust concentration in the air. Ino-Tek has designed and installed systems for this application.