Combustible Dust and Its Hazard

Combustible Dust and Its Hazard

Combustible dusts are present in a great variety of industries. It is estimated there are about 13 million workers in the manufacturing industry and of these, thousands may be at risk of injury related to combustible dust.

 In the last decade there have been several serious explosions and hundreds of smaller explosions, all related to the dangers of combustible dust. The most recent explosions which have been more damaging are

•  Iimperial Sugar (Georgia) - 14 dead and 36 wounded, destruction of the sugar refinery and an 8 million fine to the employer for safety violations.
• West Pharmaceutical (North Carolina) - 6 dead and 38 wounded. Almost total destruction of the facility caused by dust explosion processes of plastics and resins
• CTA Acoustics (Kentucky) - 7 dead and 37 injured by explosion of powder phenolic resin, in addition to partial destruction of the facility.
• Hayes Lemmerz International (Indiana) - manufacturing aluminum wheels. The explosion caused one dead and six injured and extensive damage in the building.

These figures demonstrate the seriousness of a fire or explosion event in areas where combustible dusts are present

Important Concept

There are several definitions but all agree that it is a very small particulate that when dispersed in air has the ability to explode under certain conditions. The NFPA 654 (2006) defines it as a combustible dust particulate solid that presents a risk of fire or explosion, regardless of size or shape, when suspended in air (or other oxidant) at various concentrations. This was the definition adopted by OSHA for its National Emphasis Program, launched in 2008. There is evidence that even when the particulate is not spherical, but behaves as such, it will present an explosion hazard. The following will be considered as solid particulate matter

• dust

• fibers

• fragments

• flakes

• chips, or

• mixtures of any of the above mentioned.

Which industries are at risk?

As mentioned, any organic solid particulate, or inorganic in the case of metals, has the potential to cause an explosion under the right conditions. Recognized as common sources of particulate material are industries handling, metal, plastic and / or resins, wood and wood products, food, also drug manufacturing, and manufacturing of agricultural products among others.

How small is this particulate?

When compared to known materials, it can be as or smaller than

• a grain of sugar or sand                                          

• fine wood sawdust 

• the flour used for baking bread

• metal powder after grinding or cutting

How much accumulation is necessary to become dangerous?

As little as 1 / 32 "inch (less than the thickness of the coin) on horizontal surfaces can cause problems

How is the solid particulate generated?

Is generated as a result of mechanical processes where solid matter is cut, sanded, polished, crushed, ground or otherwise manipulated to generate fine particulate solid