Experimental Evaluation of Three Local Exhaust Ventilation Systems Designed to Reduce Ultrafine Dust Emission During a Polishing Process

Aerosol transport is a fundamental phenomenon in many environmental and industrial applications. The study of the dispersion of aerosols, such as contaminants, in the workplace and the search for solutions to capture them are the biggest challenges currently faced in the field of occupational safety and health. In addition, laws and regulations that limit the level of worker exposure to contaminants in workplaces are becoming stricter. The aim of this study was to help reduce exposure to dust, including crystalline silica dust, emitted during the granite polishing process. During this process, the ultrafine particles generated are more difficult to capture than the fine ones, especially in rotational polishing, which causes the worst cases of dust exposure. An experimental test bench was set up to simulate ultrafine particle dispersion and assess three solutions for reducing worker exposure during the rotational polishing process. The use of the test bench allowed experiments to be performed while avoiding human exposure. Results showed that the test bench efficiently simulated the dispersion of ultrafine particle dust. Three solutions designed to reduce dust emissions, based on local exhaust ventilation, were evaluated on the test bench: a push–pull system, a dust shroud and a tool with integrated suction slots. They proved to be more than 95% effective. The results of this work highlight that the performance of local exhaust ventilation systems is very sensitive to the suction flowrate and the speed of the rotating disc, thus illustrating the complexity of dust removal associated with polishing processes in industrial environments.