What is dust?

Dust and fume can be generated in a variety of different ways and occur in almost all process and production applications. Dust generation takes place in many ways and can include interaction with solid materials such as grinding and fettling, sawing, sanding and polishing, or where hot metal processes such as welding, plasma or laser cutting are being undertaken. Melting metal processes that use electric arc or gas furnaces can also generate fume.

Dust generating applications also include, but are not limited to, powder coating, shotblasting, mixing, weighing, crushing, size reduction, sack tipping, punching and folding and wire drawing.

Material handling processes such as conveyor transfer points, screening, sieving and the handling of displaced air from vessels can also generate dust.

Why is dust dangerous?

Dusts and fumes consist of small solid particulate which, when airborne and not controlled, present a serious health hazard to workers.

These include conditions which can lead to lifelong debilitating illnesses and, in some cases premature death.

Airborne particulate can also lead to increased maintenance requirements and therefore additional unnecessary cost for the upkeep of plant and machinery. It can also mean the unnecessary uprating of ATEX zoning in production and processing areas leading to further additional costs to businesses.

Dust control – factors to consider

Dust and fume clouds are made up of a variety of different characteristics with each one needing to be taken into account when selecting a correct LEV (Local Exhaust Ventilation) solution. This includes whether the particulate is fine or coarse, dry or sticky, dense and heavy or light and fly away, inert or potentially explosive, produced intermittently or on a constant basis, etc. At the core of any LEV system is the design of the hooding required to capture the airborne contaminant as this determines the extraction air volume which, when coupled with the dust or fume characteristics, leads to the selection of the specification of the filter unit and the size of the extraction fan set.

Other factors include the materials of construction for the filter unit and interconnecting ductwork, together with how to protect the filter unit and plant should the dust be potentially explosive.

This can include the use of sacrificial explosion relief panels, or internal flameless vents to protect the filter unit body, as well as non-return valves in the ductwork to de-couple the filter unit from the extraction process.