The surface preparation industry does not use “dustless” or “dustless-free” blasting. Under normal operating conditions, abrasive blasting equipment produces dust.
According to air quality studies, vapor abrasive blasting machines suppress no more than 92% of the dust produced by dry blasting. You may be misled by manufacturers who claim their equipment is “dustless” or “dust-free”. For more information, visit sablagesanspoussiere.net.
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How Dust Occurs
A particle of abrasive media breaks into smaller particles when it shatters. During a blasting process, air turbulence produces air turbulence that prevents the smallest particles from making it to the ground.
The original particle is encapsulated to varying degrees in a water jacket during wet blasting. The ensuing wet sub-particles are weighed down by the water after the particle shatters, and gravity pulls them to the ground regardless of air turbulence.
However, some sub-particles are so small that even when encapsulated in water they do not take on enough mass to counteract the force of air turbulence, and they linger suspended in the atmosphere. Additionally, not all sub-particles are encapsulated in water jackets. The sub-particles emitted from the dry interior of the original particle may not become moistened at all. It is for this reason that there is no wet-based blasting system that can completely eliminate dust.
The Economic Risk
In the event that a blaster invests in equipment believing it will eliminate dust, his misconceptions can prove costly. Perhaps one could reasonably assume that, in the absence of dust, there would be no need to construct containment, saving both time and money.
SSPC classifies all vapor abrasive blasting systems in the same category, and although the requirements are less strict, they still exist. Even though the “dustless” hobbyist might be able to flout EPA standards and ignore containment requirements, a contractor working on a project that complies with the laws will be required to contain the site equally with other vapor abrasive blasters.
The Health Risk
Blasting operators wear breathing protection to protect their lungs from dust, heavy metals, and other harmful particulates. A particular concern is silica dust, which causes silicosis, a deadly occupational lung disease that kills over 100 Americans each year. More than 2 million U.S. workers are exposed to respirable crystalline silica, according to the CDC. If a blaster thinks his process does not produce dust, he may reasonably assume that breathing protection does not need to be worn.
Why not use silica sand instead of the other abrasives if his equipment is “dustless”? Silica sand blasting has a stigma attached to it because of silicosis caused by silica dust. It is difficult to imagine how dust-free conditions could pose a threat to silicosis. It’s important to be skeptical of manufacturers who claim their systems are “dustless” or “dust-free” but do not recommend blasting with silica sand. Why would they recommend anything other than the most cost-effective abrasive?
Silica was the subject of a new OSHA rule, which took effect on June 23rd, 2016. OSHA’s website states that the final rule was created to curb lung cancer, silicosis, chronic obstructive pulmonary disease and kidney disease among Americans by limiting their exposure to respirable crystalline silica.
When manufacturers claim their blasting equipment does not produce dust, they tread on a dangerous slope: when blasters believe their blasting system does not create dust, they may make potentially fatal decisions.
What You Can Do To Protect Yourself
Request that the manufacturer provide you with an air quality report written by a respected, neutral third party before you invest in abrasive blasting equipment. Conscientious manufacturers who make dust-suppressing claims will have taken the time to research to what extent their product suppresses dust, and will never make indefensible claims that endanger the health of their customers