Echt Alan S, Sanderson Wayne T, Mead Kenneth R, Feng H Amy, Farwick Daniel R, Farwick Dawn Ramsey
a Division of Applied Research and Technology, National Institute for Occupational Safety and Health , Cincinnati , Ohio.
b Department of Epidemiology , University of Kentucky , Lexington , Kentucky.
J Occup Environ Hyg. 2016 Sep;13(9):718-24. doi: 10.1080/15459624.2016.1177644.
Rotary-type percussion dowel drilling machines, which drill horizontal holes in concrete pavement, have been documented to produce respirable crystalline silica concentrations above recommended exposure criteria. This places operators at potential risk for developing health effects from exposure. United States manufacturers of these machines offer optional dust control systems. The effectiveness of the dust control systems to reduce respirable dust concentrations on two types of drilling machines was evaluated under controlled conditions with the machines operating inside large tent structures in an effort to eliminate secondary exposure sources not related to the dowel-drilling operation. Area air samples were collected at breathing zone height at three locations around each machine. Through equal numbers of sampling rounds with the control systems randomly selected to be on or off, the control systems were found to significantly reduce respirable dust concentrations from a geometric mean of 54 mg per cubic meter to 3.0 mg per cubic meter on one machine and 57 mg per cubic meter to 5.3 mg per cubic meter on the other machine. This research shows that the dust control systems can dramatically reduce respirable dust concentrations by over 90% under controlled conditions. However, these systems need to be evaluated under actual work conditions to determine their effectiveness in reducing worker exposures to crystalline silica below hazardous levels.
用于在混凝土路面钻水平孔的旋转式冲击销钉钻孔机，已被证明会产生高于推荐接触标准的可吸入结晶二氧化硅浓度。这使操作人员面临因接触而产生健康影响的潜在风险。这些机器的美国制造商提供了可选的粉尘控制系统。在受控条件下，在大型帐篷结构内运行机器以消除与销钉钻孔操作无关的二次接触源，评估了粉尘控制系统对两种钻孔机上可吸入粉尘浓度的降低效果。在每台机器周围的三个位置，在呼吸区高度采集区域空气样本。通过随机选择控制系统开启或关闭的相同数量的采样轮次，发现控制系统可将一台机器的可吸入粉尘浓度从几何平均值每立方米54毫克显著降低至每立方米3.0毫克，另一台机器则从每立方米57毫克降低至每立方米5.3毫克。这项研究表明，在受控条件下，粉尘控制系统可将可吸入粉尘浓度大幅降低90%以上。然而，这些系统需要在实际工作条件下进行评估，以确定它们在将工人接触结晶二氧化硅的水平降低到危险水平以下方面的有效性。
