How to properly handle combustible dust

Combustible dust is a risk in many industrial processes

How you can prevent combustible dust from exploding

During the processing of a variety of raw materials, blasting, crushing, grinding, or sanding produces small particles of combustible dust. These particles are often too small for the human eye to see. The dust particles consisting of combustible material are more dangerous than the combustible material because their size contributes to an increase in surface area. This enlargement creates the risk of an explosion because the dust has a larger surface area and burns faster.

 

Metal grinding requires the right solution for combustible dust
Metal grinding requires the right solution for combustible dust

The risk of explosion in a work environment is caused by the high concentration of dust on surfaces and in the air. Over time, the dust particles accumulate and form multiple layers in the atmosphere and on surrounding surfaces. If the dust ignites, there is a risk of enormous explosions that can be triggered by the high concentration of combustible, ignitable and fast-burning dust.

Most of the organic materials used in industrial processes such as wood, sugar, and grains are combustible. Other small dust particles generated in the pharmaceutical, textile, rubber, plastic and some metals processing are also combustible.

Regulations on combustible dust

Having recognized the hazards posed by combustible dusts, the European and U.S. governments have developed policies for dealing with these dusts and have ensured that appropriate measures are taken to capture dusts from industrial processes to prevent the risk of fires.

Most workplaces are affected because most types of dust pose a fire risk. Therefore, employers are expected to take measures to protect their workers and their facilities from such accidents. Regulators are ensuring that all industries that generate combustible dusts have taken steps to capture the dust at its source. This prevents the dust from spreading and settling in hard-to-reach areas.

Employers are also expected to use safe dust extraction methods that prevent the risk of explosion during the extraction process.

How can you identify vulnerable areas or equipment?

Combustible dust can pile up on any surface in your facility.
Combustible dust can pile up on any surface in your facility.

Because dust particles are light, it requires minimal effort for the dust to be blown away either when cleaning or due to machine motions. When the dust is blown, it tends to accumulate and keep piling up on roofs, ceilings, or other areas.

These areas are the most vulnerable because they are usually hard to reach and it takes a lot of time before the dust can be noticed or exhaustive cleaning is conducted. According to regulators, the employer is responsible for establishing whether their industrial processes produce dust and if the dust is combustible.

Industries are also required to adopt production methods that minimize dust collection by using appropriate tools and production methods.

Proper prevention is key

To prevent the dust from igniting, it is crucial for all the machines operating in areas where the dust is generated to be earthed and not have any source of ignition that could start a fire. Excessively hot surfaces should also be insulated because hot surfaces may initiate combustion.

It is possible and easy to prevent accidents that could be caused by the dust catching fire and exploding. The best way to protect your facility is by investing in a good dust collection system. A good system ensures that the dust is collected from the source, thus minimizing the ability of the dust to escape and settle further away.

The dust should be captured by approved dust collection systems recommended and approved for the collection of dust that is combustible. If a poor quality system is used, there is always a risk of dust catching fire within the collection systems. This can result in an even bigger explosion due to the accumulation of particles at high pressure.

The right dust collection system for combustible dust

A dust collection system should also have appropriate fire-safe transfer methods that can safely transport the dust from the collection point to the location where the dust is trapped. Workers who work in such areas and handle such machinery should also have proper training and safety equipment. This will enable them to operate and handle the equipment in a professional manner to avoid hazards that could result from improper handling.

There are two categories of collection systems that meet regulatory requirements: passive and active devices. Passive devices respond to an event, while active devices detect and act before an explosion or fire occurs.

Passive devices are used to protect employees and contain the fire in the event of an explosion. Active devices, on the other hand, are useful for preventing fires and explosions in the first place. Active devices are better, but more expensive to purchase and maintain.

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The following are some of the passive devices

  • Explosion venting
  • Flameless venting
  • Passive float valve
  • Backdraft damper
  • Flame front diverts
  • Active devices include
  • Chemical isolation
  • Chemical suppression
  • Fast acting valve
  • High-speed abort gate