Dust explosions are a result of the rapid burning of flammable mixtures, such as those found in dust clouds in a workshop environment when mixed with the surrounding air. When this mixture is combined with an ignition source, e.g. a flame, and the dust particles have gathered into a big enough group to keep the flame sustained, the dust cloud becomes combustible. Research has shown that 70% of all powders are flammable, owing to their particle size and density which allows them to sustain the flame long enough for combustion.
If the dust particles are freely moving and are heated sufficiently, this will cause a flash fire which will momentarily combust. However, if the dust particles are concentrated within a small area, such as a vent or inlet for machinery, this will cause an explosion and can result in complete destruction of the machinery and even the building.
Because it takes time for enough dust to build up and result in an explosion, proper precautions and vigilance can reduce the likelihood of an explosion from happening.
What is special about dust explosions?
The biggest cause of dust explosions is from friction and mechanical failure. Unlike gas or solvents, dust particles pose a bigger risk to workshop machinery and workers' safety. Whereas gas and solvent particles can dissipate into the air and fall below flammable levels, dust particles are heavier than air and therefore fall onto surfaces until a strong enough air current raises them back into the air where they can regroup with other dust particles. If a big enough collection of particles is made and the conditions for combustion are met, this can result in an explosion. This is why finer particles are more of a danger, because larger particles are less likely to enter the free flowing air again, whereas smaller particles are much lighter, and therefore easier for the air to carry.
This poses a very real risk for machinery such as sanders, saws, and lathes where wood waste is produced.
Invest in a Dust Extraction System
As you can see, there is plenty of reason to invest in a dust extraction system. Not only are the potential dangers to machinery and your working environment a real problem, but with all of that dust floating about in the air, improper ventilation could also affect the health of your workers and put them at undue risk.
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Dustraction are leaders in the dust extraction and wood waste management industry, located in Leicestershire and serving the UK. http://www.dustraction.co.uk
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