What is a dust explosion?
Dust explosions occur when combustible dust is airborne in a room or inside equipment. When mixed with oxygen, these fine particles can be ignited by a spark, metal ember, cigarette butt, or other ignition source. This quick combustion process is known as deflagration, and results in a high-pressure airwave. These factors are illustrated as a “Dust Explosion Pentagon” below:
As the airwave explodes out of its enclosed space, it will likely dislodge or stir up combustible dust elsewhere in the facility. This will mix the dust with the oxygen in the air, which will make the explosion bigger, and potentially fuel a second dust explosion – or even several. Some of these may occur inside other machines or containers, as the pressure wave and the fire propagate through the duct system.
Imperial Sugar Video; https://www.youtube.com/watch?v=fI-jlNqpCQ8
Dust explosions can be deadly and cause major destruction to plant and equipment. Unfortunately, combustible dust is usually a natural by-product of various common materials and manufacturing processes and cannot be avoided. However, what can and must be prevented is the potential accidents that this dust can create.
Identify the hazards:
There are a number of ways to determine if your workplace is at risk of combustible dust explosions, including:
- Review of information such as material safety data sheets (MSDS) or product information sheets
- Workplace inspections
- Consultation with employees
- Review of past incidents, health concerns, hazard reports
- Industry association information
- Incident reports from WorkSafe or other work health and safety regulator
- Specialist audits
- Look out for combustible dust thicker than a paperclip over more than 5% of surfaces
Preventing combustible dust explosions
Awareness of the issue among the personnel, proper housekeeping routines, and having the right equipment in place, are all key measures in preventing dust explosions from causing damages, injuries, or even loss of human lives.
WorkSafe recommend the following Specific controls :
- Separation of hazardous processes from other work areas
- Ventilation systems (especially local exhaust ventilation near the source)
- Dust collection equipment
- Vents on equipment where a dust explosion could occur
- Dust extraction on hand-held tools
- Separation of heat and ignition sources from combustible dusts
- Cleaning program (including areas where dust may be unseen)
The Right Equipment
The Australian Standards specify that IECEx certified equipment must be used in areas that have been deemed as potentially explosive atmospheres. This internationally recognised standard ensures that equipment is intrinsically safe and suitable for the collection of combustible dusts. At AIV we offer the largest range of IECEx Certified vacuum systems in Australia. Check out our Delfin DG50 EXP IECEx here!
(For more information on the importance of IECEx, please see our blog: IECEx The New Standard – Are You Covered?)
While the obvious place to clean may be the floor, there are lots of unseen areas in which combustible dusts can build up to dangerous levels. Accumulation of combustible dust at heights in powder processing facilities is a major concern for both primary and secondary explosion incidents. Do not neglect the highest parts of buildings as these are the areas where the finest and most hazardous dust can be found. Our AIV Antistatic Carbon Fibre Pole Kits provide a fast, cost efficient and safe way of cleaning high-level areas inside and out from the safety of the ground floor. For more info; https://industrialvac.com.au/blog/workplace-safety/carbon-poles-saving-money-time-improving-safety/