McDowell Thomas W, Welcome Daniel E, Warren Christopher, Xu Xueyan S, Dong Ren G
Health Effects Laboratory Division, National Institute for Occupational Safety and Health (NIOSH), 1095 Willowdale Road, Morgantown, WV 26505, USA
Health Effects Laboratory Division, National Institute for Occupational Safety and Health (NIOSH), 1095 Willowdale Road, Morgantown, WV 26505, USA.
Ann Occup Hyg. 2016 Apr;60(3):371-86. doi: 10.1093/annhyg/mev084. Epub 2015 Nov 30.
Mechanical arm systems are commonly used to support powered hand tools to alleviate ergonomic stressors related to the development of workplace musculoskeletal disorders. However, the use of these systems can increase exposure times to other potentially harmful agents such as hand-transmitted vibration. To examine how these tool support systems affect tool vibration, the primary objectives of this study were to characterize the vibration emissions of typical portable pneumatic grinders used for surface grinding with and without a mechanical arm support system at a workplace and to estimate the potential risk of the increased vibration exposure time afforded by the use of these mechanical arm systems. This study also developed a laboratory-based simulated grinding task based on the ISO 28927-1 (2009) standard for assessing grinder vibrations; the simulated grinding vibrations were compared with those measured during actual workplace grinder operations. The results of this study demonstrate that use of the mechanical arm may provide a health benefit by reducing the forces required to lift and maneuver the tools and by decreasing hand-transmitted vibration exposure. However, the arm does not substantially change the basic characteristics of grinder vibration spectra. The mechanical arm reduced the average frequency-weighted acceleration by about 24% in the workplace and by about 7% in the laboratory. Because use of the mechanical arm system can increase daily time-on-task by 50% or more, the use of such systems may actually increase daily time-weighted hand-transmitted vibration exposures in some cases. The laboratory acceleration measurements were substantially lower than the workplace measurements, and the laboratory tool rankings based on acceleration were considerably different than those from the workplace. Thus, it is doubtful that ISO 28927-1 is useful for estimating workplace grinder vibration exposures or for predicting workplace grinder acceleration rank orders.
机械臂系统通常用于支撑电动手动工具，以减轻与工作场所肌肉骨骼疾病发展相关的人体工程学压力源。然而，使用这些系统会增加接触其他潜在有害物质的时间，如手部传递的振动。为了研究这些工具支撑系统如何影响工具振动，本研究的主要目的是表征在工作场所使用和不使用机械臂支撑系统进行表面磨削的典型便携式气动砂轮机的振动排放，并估计使用这些机械臂系统所带来的振动暴露时间增加的潜在风险。本研究还根据ISO 28927-1（2009）标准开发了一个基于实验室的模拟磨削任务，用于评估砂轮机振动；将模拟磨削振动与实际工作场所砂轮机操作期间测量的振动进行比较。本研究结果表明，使用机械臂可通过减少提起和操作工具所需的力以及减少手部传递的振动暴露来提供健康益处。然而，机械臂并没有实质性地改变砂轮机振动频谱的基本特征。在工作场所，机械臂使平均频率加权加速度降低了约24%，在实验室中降低了约7%。由于使用机械臂系统可使每日任务时间增加50%或更多，因此在某些情况下，使用此类系统实际上可能会增加每日时间加权手部传递的振动暴露。实验室加速度测量值明显低于工作场所测量值，并且基于加速度的实验室工具排名与工作场所的排名有很大差异。因此，怀疑ISO 28927-1是否有助于估计工作场所砂轮机振动暴露或预测工作场所砂轮机加速度等级顺序。
