Department of Occupational and Environmental Health, University of Oklahoma College of Public Health, PO Box 26901, Oklahoma City, OK 72126-0901, USA.
Division of Applied Research and Technology, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Cincinnati, OH 45226, USA.
Ann Work Expo Health. 2017 Jul 1;61(6):711-723. doi: 10.1093/annweh/wxx040.
Workers who fabricate stone countertops using hand tools are at risk of silicosis from overexposure to respirable crystalline silica. This study explored the efficacy of simple engineering controls that can be used for dust suppression during use of hand tools by stone countertop fabricators.
Controlled experiments were conducted to measure whether wet methods and on-tool local exhaust ventilation (LEV) reduced respirable dust (RD) exposures during use of various powered hand tools on quartz-rich engineered stone. RD samples collected during edge grinding with a diamond cup wheel and a silicon carbide abrasive wheel were analyzed gravimetrically as well as by X-ray diffraction to determine silica content. A personal optical aerosol monitor was used simultaneously with the RD samples and also for rapid assessment of controls for polishing, blade cutting, and core drilling.
On-tool LEV and sheet-flow-wetting were effective in reducing exposures, especially when used in combination. Sheet-flow-wetting with LEV reduced geometric mean exposures by as much as 95%. However, typical water-spray-wetting on a grinding cup was less effective when combined with LEV than without LEV. Mean silica content of RD samples from grinding operations was 53%, and respirable mass and silica mass were very highly correlated (r = 0.980). Optical concentration measures were moderately well correlated with gravimetric measures (r = 0.817), but on average the optical measures during a single trial using the factory calibration were only one-fifth the simultaneous gravimetric measures.
Sheet-flow-wetting combined with on-tool LEV is an effective engineering control for reducing RD exposures during engineered stone edge grinding and blade cutting. On the other hand, addition of LEV to some water-spray-wetted tools may reduce the effectiveness of the wet method.
使用手动工具制作石材台面的工人因过度接触可吸入结晶二氧化硅而有患矽肺的风险。本研究探索了在使用手动工具时抑制粉尘的简单工程控制措施的效果，这些措施可用于石材台面制造商。
进行了对照实验，以测量在使用各种富石英的工程石材的电动手动工具时，湿法和工具上局部排气通风（LEV）是否能减少可吸入粉尘（RD）暴露。用金刚石杯轮和碳化硅磨轮进行边缘磨削时收集的 RD 样品进行了重量分析和 X 射线衍射分析，以确定硅含量。个人光学气溶胶监测仪与 RD 样品同时使用，也用于快速评估抛光、刀片切割和芯钻的控制措施。
工具上的 LEV 和片状流润湿在降低暴露方面非常有效，尤其是当两者结合使用时。带 LEV 的片状流润湿可将几何平均值暴露降低多达 95%。然而，典型的磨削杯水喷雾润湿在与 LEV 结合时不如没有 LEV 时有效。研磨操作的 RD 样品的平均硅含量为 53%，可吸入质量和硅质量高度相关（r = 0.980）。光学浓度测量与重量测量中度相关（r = 0.817），但在使用工厂校准进行的单次试验中，光学测量值平均仅为同时进行的重量测量值的五分之一。
片状流润湿与工具上的 LEV 结合是减少工程石材边缘磨削和刀片切割时 RD 暴露的有效工程控制措施。另一方面，向某些水喷雾润湿工具添加 LEV 可能会降低湿法的效果。
