Sandblasting is a dry abrasive blasting process involving forcefully projecting a stream of abrasive particles onto a surface, usually with compressed air or steam. The purpose of sandblasting is to smooth surfaces, removed jagged edges or burrs, apply texture to material or prepare a surface for coating. Silica sand is commonly used in this process, and workers who perform abrasive blasting are known as sand blasters. Sandblasting is a high-risk profession for potential development of silicosis. Due to the lack of a definite treatment of silicosis, prevention of the disease should be the main target and Global Road Technology provides innovative and effective solutions that deal with silica dust at its source. Silicosis is a major health problem associated with sandblasting and to put everything into perspective these are the occupations that utilize sandblasting:
- Denim sandblasters
- Dental laboratory technicians
- Paint removal workers
- Metal polishing
- Raw glass workers
- Teflon-pot workers
- Lathe workers
- Foundry casting workers
- Ceramic workers
In this article, GRT evaluates sandblasting based on the different occupations and provides solutions to how it can provide sandblasting dust control solutions.
Types & challenges of Sandblasting
There are different types of sandblasting, and each presents the similar challenge of exposure to different types of dust which leads to dust-related lung diseases such silicosis and pneumoconiosis. The major drawback is a lack of awareness of the hazards of silica outside of the traditional occupations with silicosis. We will focus on three occupations namely, denim sandblasters, dental technicians and surface coating removal workers.
1. Denim sandblasting
There is high-risk exposure to respirable silica particles in denim sandblasters in the occupational environment of a denim sandblaster. In denim sandblasting, workers are exposed to silica because they project silica or silica-containing sand as an abrasive onto denim (blue jean) surfaces to produce a “worn-in” appearance. This kind of exposure is very dangerous because of intense exposure during long hours of work up to 10 hours a day, 6 days a week under very poor hygienic conditions without any serious respiratory protection, ventilation systems or dust control measures in place. The other challenge experienced in almost all silicosis victims was that all cases were unregistered and uninsured and most of the workplaces tend to be unregistered or unlicensed. Research from Turkey shows that, Among the 145 former sandblasters studied in 2007, 83 were reassessed in 2011. In the 4-year follow-up period, nine (6.2%) had died at a mean age of 24 years. Of the 74 living sandblasters available for reexamination, the prevalence of silicosis increased from 55.4% to 95.9%.
2. Dental laboratory sandblasting
Dental laboratory technician as a profession has several occupational risks, primarily dust. During the prosthesis making process different types of dusts are generated and exposure to these dusts can lead to dust-related occupational diseases, if necessary, precautions are not taken. Local and general ventilation is very important in the prevention of dust exposure in dental laboratory sandblasting procedures such as grinding, preparation of metal framework for porcelain bonding and polishing methacrylate surfaces of dental prosthesis. The use of ventilation and regular vacuuming to get rid of the dust is often lacking. The use of personal protective equipment by technicians is very low and the efficient use of masks is seldom followed which increases the uptake of respirable dusts. The general working hours of dental laboratory technicians which means exposure time to dust is quite long hence the health risk is very high in dental laboratory technicians. Dental laboratories are pneumoconiosis risky environments in which various dusts such as silica dust occur. Research from Turkey shows that of 23.6% of the chest X-rays of dental laboratory technicians were compatible with pneumoconiosis. The departments that pose risk to pneumoconiosis include acrylic levelling, metal levelling, porcelain, acrylic former, plaster cast and wax pattern.
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3. Surface coating sandblasting
Coatings are used in many applications and with their use in ships, buildings, bridges and road markings they wear out and lose properties. When a surface is coated in grease, paint or another undesired veneer, a sandblaster can completely remove the residue and restore the item to its original condition. When machining leaves sharp burrs on an object, sandblasters can smooth it until it is safe to handle. Sandblasting is a common coating removal technique. Cleaning and removing paint from aircrafts, ship hulls, stone buildings, civil steel structures and road markings utilizes silica sand which fractures into fine particles and becomes airborne. Inhalation of silica dust fugitive silica dust particles and its lodging into the deepest parts of the lungs contributes to the development of acute and accelerated forms of silicosis among surface coating sandblasters. The challenges faced in surface coating sandblasting are mainly based on the % crystalline silica in silica sand which is used as a dry abrasive blasting material.
How can sandblasting dust be reduced?
Respirable crystalline silica content in silica sand used in sandblasting is the main concern, which, when breathed by sandblasters, leads to serious illness of the respiratory system. Reducing sandblasting dust can be done in the following ways:
- Wet dust suppression
- Ventilation controls
- Barriers and curtain walls
- Blast rooms or blast cabinets
- Restricted areas
- Tighter legislative controls
- Compulsory real-time silica dust monitoring
- Proper respiratory equipment
- Use of relevant semiotics
- Increased awareness of sandblasting-related dust diseases
GRT’s solutions & products
GRT solutions focus on creating wet sandblasting conditions that target the surface chemistry and charge of silica dust particles in dealing with the dry conditions associated with silica sand used in dry sandblasting. Wetting with water alone is also commonly attempted using directional sprays or even misted water sprayed directly onto the material or into the surrounding atmosphere. GRT acknowledges that there are surmountable challenges to using water alone for dust suppression. Where post sandblasting exposure to silica dust is a concern, liquid polymers are available to form a 3D network that keeps fugitive silica dust particles out of suspension. The GRT marketplace has different GRT products available for sandblasting dust control. GRT: Activate suppresses sandblasting silica dust by wetting the material to an optimal moisture content, preventing fines from being carried off into the air, or to the air above the sandblasted material, to return airborne fines to the source of sandblasting dust generation. The incentive to using GRT products is that the material does not have to be handled again. The suppressed dust returns to the main body of sandblasted material without requiring additional material handling equipment.
Conclusions
Abrasive blasting with silica sand containing crystalline silica can cause serious and fatal respiratory disease. Death from silicosis in workers exposed to silica dust due to sandblasting operations suggests that overexposure and unsafe working conditions are prevalent because of a lack of dust suppression solutions.
Find out more about wet dust suppression from Daniel Grundy and further understand how GRT can help you deploy corrective dust suppression solutions to deal with sandblasting silica dust. If it cannot be trapped, it becomes airborne and must be suppressed.
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