The hazards of respirable silica dust are well known. There are now regulations and suggested engineering controls in place to help protect workers in various industries from these hazards. Using a water delivery system to boost dust suppression is common in both construction and general industry; however, there are many nuances to proper respirable dust suppression using water.

Droplet size is a major determinant in the effectiveness of dust suppression when using a water delivery system. While water alone may be able to suppress visible dust relatively well, it is not effective in suppressing harmful respirable silica particles–this is due, in part, to the standard droplet size delivered through most water systems. Typically, water droplets sprayed into the air range from 200 μm to 1000 μmin size. When these larger particles move through the air, they push away lighter silica particles, causing silica dust to remain airborne, or “fugitive.” This issue is called the “slipstream effect” because the silica particles literally slip past the water stream, avoiding suppression.¹ 

Spraying smaller water droplets (or a mist), ranging from 10μm to 200 μmin size, is the best solution to this problem. Because mist causes very little slipstream, it is a superior form of dust suppression. The best method to achieve a mist is by using an atomized nozzle. Atomized nozzles produce water droplets that maintain a high velocity over a long distance. These are widely considered the most effective nozzles at reducing dust, especially respirable dust.²

Using NeSilex with an atomized nozzle is the most effective solution for maximum silica dust control. If creating a mist is not an option in your operations, NeSilex is an even more important addition to your silica dust suppression efforts. NeSilex’s unique properties allow it to chemically change water droplets to make water more attractive to dust particles. One of the components of this chemical change is the reduction of surface energy. Lower surface energy allows the water to suppress the otherwise fugitive respirable dust because of its improved wetting ability. NeSilex is able to dramatically improve larger water droplet’s ability to suppress dust; however, combining this NeSilex with an atomizing nozzle is by far the most effective way to suppress respirable silica dust, protecting both workers and civilians.

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Sources:

¹ Silica Dust Control. Bosstek. https://bosstek.com/silica-dust-compliance/silica-spraying-problems/. Publish date not available. Accessed July 25, 2019.

² Gottesfeld, Perry, Kephart, John, Balakrishnan, Kalapna, and Rinehart, Richard. Reduction of Respirable Silica Following the Introduction of Water Spray Applications in Indian Stone Crusher Mills. Semantic Scholar. https://pdfs.semanticscholar.org/ce38/2f4ef3611bd74642497eb1ec85c69448eb67.pdf. Published April, 2008. Accessed July 25, 2019.