Understanding the Dangers: The Risks and Prevention of Flour Dust Explosions 

On 19th May 2018, a flour mill explosion in NSW made headlines demanding attention to the risk of a flour dust explosion. Although nobody was injured, the disaster was a wake-up call for organisations and flour mills. The Police had handed over the investigation to the Mill and SafeWork.

As unbelievable as it may sound, flour dust is 35 times more flammable than coal dust and more explosive than gun powder. Hence, it is essential to understand the risk of flour dust explosion and implement strict measures to prevent the hazard.

In this blog, we discuss the dangers and risks of industrial flour dust explosions and prevention techniques to curb them.

Flour Dust Explosion

Flour Dust is mostly formed of starch, a complex carbohydrate composed of glucose molecules that is extremely combustible. The combination just needs one to two grammes of dust per cubic foot of air to ignite it.

Due to its flammable nature, flour dust has the potential to explode when exposed to certain substances. The buildup of flour dust over a period of time is one of the key reasons for the explosion.

These dust explosions pose major risks and have the potential to damage property and corporate assets as well as, more tragically, result in injuries and fatalities.

At practically every stage of the production process at flour mills, including initial grinding, loading, sifting, drying, and packing, airborne dust particles are discharged into the air.

Cause of Flour Dust Explosion 

Flour dust explosions are often caused by a combination of flour dust, an ignition source, a small space, dispersion, and oxygen.

All these components may come together in an environment produced during the manufacturing of flour. As a result, when combined with oxygen, wheat dust works as a fuel source that, when enclosed in a small space, can start a fire.

In other words, when flammable dust is airborne inside machinery or in a room, dust explosions might occur. These tiny particles may ignite using any kind of ignition source when combined with oxygen.

The use of sandpaper, brushed metal, saws, and cutting tools in environments with flour dust can generate sparks or friction, which can serve as ignition sources for a flour dust explosion if the dust concentration and other conditions are within the explosive range.

The risk does not just apply to flour mills. Commercial bakeries and food producers who use flour incur the risk of combustion as well as producing large amounts of flour dust.

Understanding Dangers and Risks of Flour Dust Explosion

Combustible dust explosions in mills and manufacturing plants have been the cause of several serious occurrences in Australia and the world.

The belief that a facility is safe because it has been in operation for years without experiencing a dust explosion in mills and manufacturing facilities is a typical error made with flour dust. Nevertheless, it’s crucial to understand that this cannot be used to assess how well you are truly preventing a dust explosion. The most likely scenario is that you have simply been extraordinarily lucky, and it hasn’t occurred yet. When employee safety is at risk, running a firm based on mere luck is not an option.

Risks Associated With Flour Dust

Although wheat dust is flammable and can explode, it can also be harmful to breathe in. Breathing in high amounts of grain and wheat for an extended length of time can have an adverse effect on employees’ health and general comfort, which can compromise safety and morale.

A person can suffer from a severe headache, muscle pain, chest tightness, and nausea when exposed to the flour dust. Asthma, inhalation issues, shortness of breath, baker’s lung, wheezing, lung fibrosis, irritated rhinitis, chronic bronchitis, and organic dust toxic syndrome are all potential complications in severe cases. Inhaling flour dust can also cause breast cancer.

Suffocation is another significant problem that many employees deal with; it is a leading cause of fatalities in the storage bin.

Risks Related to Flour Dust Explosion

Many people think that a mill must be safe if it has been operating for years without an explosion or fire. This is untrue since flammable dust debris can gather anywhere and at any moment.

Explosions using flour have been reported to seriously harm the plant and result in worker fatalities. Equipment including dryers, classifiers, mixers, conveyors, and hoppers are frequently where explosions occur.

Flour Dust Monitoring by Occupational Hygienist

Flour dust can also impact on the health of employees when the levels are above the occupational exposure limit. Occupational hygienists are able to monitor flour dust in workplaces to mitigate health risks to employees and prevent explosions. They use advanced air sampling techniques to measure airborne flour dust concentrations, ensuring they stay within safe limits. Regular monitoring helps identify high-risk areas where dust is generated, allowing for targeted occupational hygiene solutions such as improved ventilation and dust extraction systems. Hygienists also provide training on safe handling practices and the use of personal protective equipment (PPE) to reduce exposure. This comprehensive occupational hygiene management approach ensures a safer and healthier work environment.

Dust Explosion Prevention In The Workplace

Safeguard the area where you operate against hazardous dust explosions. This practical advice and solutions can help you ensure safety on your property and remove dust.

1)    Elimination Of Potential ‘Danger Spots’

Eliminating these horizontal gaps and concealed regions might result in the lives of your employees being saved because prevention is always preferable to treatment in the case of dust explosions. These regions and spaces consist of:

1. Light fittings.
2. Window.
3. Beams.
4. Ledges.

Avoid using compressed air hoses or brooms for cleaning. Use commercial vacuum cleaners that have been certified for collecting dust instead.

2)    Substitution Of Rough Surfaces With Smoother Ceilings

Dust is particularly attracted to rough surfaces. To reduce dust accumulation and to make routine cleaning simpler and more effective, smooth ceilings should be used as a replacements.

3) Curtain Wall Architecture or Cladding

Curtain wall architecture or cladding, also known as explosion isolation or containment systems, can be used in industrial settings to mitigate the effects of flour dust explosions. These systems create physical barriers between areas or equipment to contain explosions within a specific zone. The curtains are made of flame-resistant materials and are activated by sensors. Curtain architecture can also include venting systems to release explosion pressure safely. Reinforced construction techniques can be employed to enhance the system’s effectiveness, and monitoring and detection mechanisms should be in place. Qualified professionals should design and implement the system while adhering to safety standards. Regular maintenance and testing are essential for its functionality.

4)    Collaborating with Experienced Occupational Hygienists

Organisations should collaborate with an experienced service provider that has years of expertise setting up dependable dust-collecting systems and is knowledgeable about how to properly plan, develop, and install dust collection and extraction systems.

They should be capable to:

1. Use dust collection systems with the intake situated as close to the dust-producing process and Duce surfaces where dust might build.
2. Choose proper electrical and ventilation equipment and place dust collectors outside.
3. Bonding and grounding of equipment can reduce or completely eliminate sparks caused by static electricity.
4. Eliminate friction, heat sources, open flames, sparks, and other ignite sources.
5. To reduce the number of places where dust might collect, wrap pipes and cables in coverings or, if feasible, bury them in the walls.

5)    Installing Explosion Vent And Pressure Relief Systems

The installation of explosive vents is one of the most popular explosion prevention techniques. These aid by preventing explosives from exploding in all directions and instead channelling them down a path that has been selected to be kept free or minimised for use. Explosion panels can potentially save a lot of lives.

Select a business with knowledge and expertise in the design and choice of the proper explosive vents. Identify their technical capabilities to confirm the suggested installation design panels and recommended explosive vents satisfy standards.

6)    Electrical Connections to Prevent Explosion

Plant or project operators can take further precautions to prevent accidents in addition to preventative maintenance and constant cleaning, which are essential for preventing dust accumulation. Electrical connections can reduce dust explosions by preventing sparks from the connector from lighting the dust on fire. The possibility of a spark can be decreased by having a regulated and secure region where the wires enter the connector or where the contacts join. To prevent dust from entering the connector, connectors must also be ingress-protected.

The connector’s design to seal and protect the electrical components, rather than the materials used to manufacture it, is crucial in reducing the likelihood of dust explosions. For instance, caulking can eliminate the possibility of a spark where the cable wires interact with the contacts. Either a gland on a cable connection or a machine enclosure can be used for this.

7)    Scheduled Inspection, Repair and Maintenance 

The effectiveness of dust collecting and explosion venting in preventing and decreasing the effects of dust explosions relies on their efficiency in functioning. Hence, businesses should inspect, repair and maintain dust-collecting systems, explosion vents, and panels regularly.

The requirements for repairing the dust collector and its maintenance include the following:

1. Maintaining the integrity of all mechanical and electrical equipment.
2. Continuously checking the integrity of the bonds on all grounded and bonded equipment.
3. Inspecting equipment for potential wear items such as bearings and valves

8)    Developing Safety practices to Prevent Dust in the Workplace

To reduce dust formation and dust explosion prevention, organisations should develop a clear administration and business process in the workplace.

The below-given steps can help you in achieving the same.

1. Creating and implementing a combustible dust inspection and control programme that would specify the frequency of inspections and the manner in which, dust would be managed.
2. Creating and implementing an ignition control program to reduce, if not completely eliminate, potential sources of ignition.
3. Educating all employees about combustible hazards and how they can help reduce the risk of fire and explosions in the workplace.
4. Implementing the housekeeping program to ensure that dust is removed on a regular basis.

If you want Anitech’s experienced Occupational Hygienists to assist your Company in preventing flour dust explosions, contact us today at 1300 802 163 or email us at sales@anitechgroup.com

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