Dust Explosion Hazards
Can Flour Explode?
Did you know that flour dust is more explosive that gunpowder, and 35 times more combustible than coal dust? This doesn’t mean that the pack of flour in your cupboard poses the threat of explosion to you, there needs to be a much larger quantity for that. But in a processing or storage setting, a dust cloud of any combustible material is likely to explode if:
- the concentration of dust in air falls within the explosion limits
- a source of ignition is present of the required energy
Explosive dusts in the food industry include materials like: flour, instant coffee, custard powder, dried milk, sugar, powdered potato and soup powder. Food industry explosions and fires from combustible dust are a well known hazard that can have devastating and irreversible effects.
Food Industry Explosions & Fires Caused by Dust
A report released in 2021 by Dust Safety Science, showed the indisputable facts around the hazards of combustible dust. Incidents from around the globe include:
A total of 163 fires and 53 explosions caused 215 injuries and 69 fatalities during 2021
In 2020 60 explosions and 165 fires were the cause of 88 injuries and 10 fatalities
2019 saw 250 fires and 75 explosions cause 118 injuries and 8 fatalities
In around 4 years Dust Safety Science logged 960 fires, 357 explosions, 720 injuries and 126 fatalities from over 40 countries
In 2021, the increase in injuries and fatalities were due to a mine explosion and fire in Gramoteino, Russia. This catastrophic event accounted for over 49% of the injuries and 73% of the fatalities that year.
Reduction of Hazardous Dust in Food Processing Plants
Almost 75% of the fires and explosions recorded were related to food and wood products, although these materials accounted for only 23% of the injuries and 12% of the fatalities. The research found that the most deadly material was coal dust, responsible for over 53% of the injuries and 87% of fatalities in 2021. Again, this is largely due to the mine explosion and ventilation fire in Russia. Other figures include two separate aluminium dust explosions resulted in twelve metal dust injuries, and one fatality. Also four injuries were the result of an explosion at a zinc powder facility.
Nine injuries from textiles were sustained when there was an explosion at a packaging production plant. Materials ignite more readily or at low energy where solid substances are finely ground. When contained materials ignite a violent explosion can occur, uncontained materials igniting can cause a fireball.
Proactive Risk Reduction, Proper Plant Maintenance & Staff Training
Hazard reduction includes eliminating one of the five elements responsible for a flour dust explosion (dust, ignition source, dispersion, confined space and oxygen). In places like fully operational flour mills, this is extremely difficult. There are factors like static electricity, pulleys that rub and friction sparks. Flour handling systems such as bucket elevators, transfer bins and baghouses increase the risk of combustion.
Risk can be reduced in a number of ways, such as:
- Preventative maintenance, training and education of workers
- Implementation of processes that generate less flour dust
- Improving work policies to decrease dust accumulation
- Implement warning signs
- Improve cleaning practices
- Ensure any required processing plant modifications are carried out