August 21st, 2019
Sandblasting uses compressed air or water to bombard a surface with a high-velocity barrage of abrasive particles. Crystalline silicates have been used ubiquitously as an abrasive media in both architectural and industrial sandblasting for decades: in the removal of flaws or applied coatings; for the application of surface roughness and textures; and in the preservation of durable and historically-valuable stonework. However, silica-based blasting media have fallen out of favor for several reasons:
1. Crystalline silica is inefficient compared to novel engineered abrasives, requiring longer sandblasting periods and potentially multiple cycles to achieve the desired surface finish.
2. Silica-based blasting media degrades rapidly and cannot be recycled for multiple use cycles, representing a poor product service life and increased operating costs over time.
3. Free silica in sandblasting environments represent a significant health and safety risk for operating and incident personnel who may accidentally ingest free-flowing silica particles.
In this blog post, Saint Gobain will focus on the third point, exploring the hazards of free silica in sandblasting applications.
Sandblasting with abrasive media that contains crystalline silica has been linked to serious and fatal respiratory diseases due to inhalation of free silica.
Free silica refers to a portion of the crystalline silica particles that have been ejected from the nozzle of the sandblaster and entered the working environment. Some break down to smaller macro particles during processing while others become airborne as microcrystalline dust. It is the latter that causes such significant health and safety concerns for personnel in the operating environment.
The National Institute for Occupational Safety and Health (NIOSH) has established strict guidelines on preventing the propagation of free silica from sandblasting in a range of markets, due to causal links between crystalline silica inhalation and various respiratory diseases. General irritation of the respiratory system, silicosis, and lung-cancer have all been quantitatively linked to chronic exposure to free silica in working environments. In fact, due to these health risks, producers of silica sand products ceased supporting sandblasting applications as early as the 1990’s, leaving all liability with entities that continued blasting with sand thereafter.
NIOSH has established several engineering controls to limit the hazards of free silica and develop a safe working environment for operators of sandblasting equipment. Air compression techniques should be replaced with a waterjet, as abrasive slurries tend to generate less dust than air delivery systems. It is also prudent to isolate, contain, and ventilate dust from sandblasting working environments.
The preferred substitution, however, is to replace crystalline silica with a less toxic abrasive material.
Saint-Gobain Abrasive Materials has developed a proprietary abrasive media for sandblasting applications, based on a unique engineered particle system with low-dusting performance. It is delivered with a guaranteed 0% free crystalline silica, eliminating health and safety concerns associated with silicosis and silica-related illnesses. Spartan Blasting Media from Saint-Gobain puts personnel safety above all else, effectively eliminating the hazards of free silica from processing environments.