How you can prevent combustible dust from an explosion during collection
During the processing of combustible raw materials, small particles of dust are created by the processes of blasting, crushing, milling, or grinding. These particles are often too small for the human eye to see. The dust particles made up of combustible materials are more dangerous than the combustible material because their size contributes to an increase in surface area. This increase poses the risk of explosion because the dust has more surface area and burns faster.
The risk of explosion in a work environment is brought about by the high concentration of dust in surfaces as well as in the air. As time goes by, specks of dust begin to accumulate forming several layers in the atmosphere and the surrounding surfaces. If the dust is ignited, there is a risk of enormous explosions that can be fueled by the high concentration of combustible dust that is ready to ignite and burns at a fast rate.
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
Upon realizing the risks posed by combustible dust, the European and American governments have come up with policies on dealing with this dust and ensuring that proper measures have been taken to collect the dust from industrial processes, thus preventing the risk of fire.
Most workplaces are affected because most types of dust generated pose a risk of fire. As such, employers are expected to set up measures to protect their workers and their facility from such accidents. The regulators ensure that all the industries that produce dust that is combustible have put up measures to collect the dust from the source. This prevents the dust from spreading and settling in hard to reach areas.
Employers are also expected to use dust collection methods that are safe and capable of preventing the risk of explosion during the collection process.
How can you identify vulnerable areas or equipment?
Because dust particles are light, it requires minimal efforts 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, ceiling, 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.
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 collection of dust that is combustible. If a poor quality system is used, there is always a risk of the dust catching fire within the collection systems. This can result in an even bigger explosion due to the accumulation of particles at high pressure.
A dust collection system should also have appropriate fireproof methods of transmission that can transmit the dust safely from the collection point to where the dust is contained. Workers who operate in such areas and handle these machines should also have adequate training and safety equipment. This enables the workers to operate and professionally manage the equipment to prevent hazards that might arise due to poor handling.
There are two categories of collection systems that are compliant with regulatory standards: the passive and active devices. Passive devices function by reacting to an event while active devices operate by detecting and acting before an occurrence of explosion or fire.
Passive devices are used to protect the employees and contain the fire in a case on a blast. Active devices, on the other hand, are useful in preventing fires and explosion from happening in the first place. Active devices are better but are more costly to acquire and maintain.
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