Control Technology Assessment Of Arc Welding Operations

This research fulfills a need for an updated assessment of engineering control technology used by the welding industry, to reduce worker exposures to toxic substances found in welding fumes and gases. The objectives of this investigation were to (1) identify and summarize research studies in the literature which provide information on the control of worker exposures to arc welding fumes and gases, and (2) provide recent data collected by the author on the effectiveness of existing control measures in the field. Prior to collecting data, the author conducted walk-through surveys at numerous welding shops to gain a basic understanding of various arc welding operations, hazards associated with these operations, and control measures that are currently in use by industry. Then, nine in-depth case studies were conducted of actual arc welding operations to identify worker exposures to toxic welding fumes and evaluate the effectiveness of existing engineering control measures in reducing welding fume exposures. This was accomplished by collecting industrial hygiene air samples, assessing control measure performance, and documenting work practices. Four of the case studies, representing four types of engineering controls for welding operations, are presented in detail in this paper. Pertinent data and observations collected during the other five case studies are also discussed. From the information presented, readers will gain an understanding of the actual effectiveness of certain engineering control methods in the field and whether the data does or does not support the findings of other welding fume control research (primarily laboratory-based). In addition, the data will show how typical welding fume exposures compare to current occupational exposure limits and will demonstrate the range of welding fume exposure levels for several of the more common base metals (carbon steel, stainless steel, aluminum) and four of the most common arc welding techniques (shielded metal, gas metal, flux cored, and gas tungsten). This paper is also a useful technical reference for occupational safety and health engineers and industrial hygienists who are unfamiliar with arc welding processes, their hazards and available control methods.