Flynn Michael R, Susi Pam
Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, NC 27599-7431, USA.
Ann Occup Hyg. 2012 Aug;56(7):764-76. doi: 10.1093/annhyg/mes018. Epub 2012 Mar 29.
Arc welding is a common unit operation in the construction industry, where frequent changes in location and welding position make it more difficult to control fume exposures than in industries where fixed locations are the norm. Welders may be exposed to a variety of toxic airborne contaminants including manganese (Mn) and hexavalent chromium (CrVI). Local exhaust ventilation (LEV) is a well-known engineering control for welding fumes but has not been adopted widely in the construction industry. This literature review presents data on the performance of a variety of LEV systems for welding fume control from the construction (five references), shipyard (five references), and other industries. The studies indicate that LEV can reduce fume exposures to total particulate, Mn, and CrVI to levels below currently relevant standards. Field studies suggest that 40-50% or more reduction in exposure is possible with portable or fixed LEV systems relative to natural ventilation but that correct positioning of the hood and adequate exhaust flow rates are essential. Successful implementation of extraction guns for gas metal arc welding (GMAW) and flux core arc welding has been demonstrated, indicating that a successful balance between extraction airflow and shielding gas requirements is possible. Work practices are an important part of achieving successful control of fume exposures; in particular, positioning the hood close to the arc, checking exhaust flow rates, and avoiding the plume. Further research is needed on hood size effects for controlling welding fume with portable LEV systems and identifying and overcoming barriers to LEV use in construction.
电弧焊是建筑业中常见的单元操作，与固定场所为常态的行业相比，其位置和焊接位置频繁变化使得控制烟尘暴露更加困难。焊工可能会接触到多种有毒空气污染物，包括锰（Mn）和六价铬（CrVI）。局部排风通风（LEV）是一种众所周知的控制焊接烟尘的工程控制措施，但在建筑业中尚未得到广泛应用。这篇文献综述展示了来自建筑行业（五篇参考文献）、造船厂（五篇参考文献）和其他行业的各种LEV系统控制焊接烟尘性能的数据。研究表明，LEV可以将总颗粒物、锰和六价铬的烟尘暴露降低到当前相关标准以下的水平。现场研究表明，相对于自然通风，便携式或固定式LEV系统有可能将暴露降低40%-50%或更多，但烟罩的正确定位和足够的排气流量至关重要。已证明成功实施了用于气体保护金属极电弧焊（GMAW）和药芯焊丝电弧焊的抽气枪，这表明在抽气气流和保护气体要求之间实现成功平衡是可能的。工作实践是成功控制烟尘暴露的重要组成部分；特别是，将烟罩靠近电弧定位、检查排气流量并避免羽流。对于使用便携式LEV系统控制焊接烟尘的烟罩尺寸效应以及识别和克服建筑业中使用LEV的障碍，还需要进一步研究。
