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The effect of two ventilation methods on weld fume exposure in a shipyard confined-space welding task.
Wurzelbacher-S; Johnston-O; Hudock-S; Blade-L; Shulman-S
American Industrial Hygiene Conference and Exposition, June 2-7, 2001, New Orleans, Louisiana. Fairfax, VA: American Industrial Hygiene Association, 2001 Jun; :36-37
Recent NIOSH studies have indicated that shipyard confined-space welding presents unique fume exposure control problems. Limited options for worker positioning (in reference to the air flow direction) and posture (in regards to the weld fume plume) can significantly affect weld fume exposure, resulting in eight-hour TWAs for PBZ concentrations that exceed evaluation criteria for welding fume and individual metals. To determine the effectiveness of available ventilation options for a specific shipyard, two ventilation methods were studied on three volunteer welders (2 male, 1 female) who performed confined-space stick welding as part of their typical work. The first method, which was currently being employed at the shipyard for this task, was a type of forced turbulence which directed air into the confined space with an electric blower. The second method, which was suggested by NIOSH, involved local exhaust of the confined space through a newly placed opening in the bulkhead via an air horn. In addition to evaluating ventilation methods, the welders' full shift exposures to welding fume were also assessed. Local exhaust was associated with significantly lower (p < .05) PBZ total particulate concentrations than forced turbulence for subjects using the same air horn. Although the performance of air horns varied, the overall reduction due to local exhaust method versus the current method was estimated to be 75 % (two sided confidence limits = 58 %, 85 %). Eight-hour TWAs for PBZ concentrations were determined to exceed evaluation criteria for welding fume (ACGIH: 5 mglm3) and individual metals using either ventilation method. Current PPE (half-face respirator) that was being used provided adequate protection at these levels.
Shipyard-workers; Shipyard-industry; Confined-spaces; Welding; Fumes; Exposure-levels; Workers; Work-environment; Work-areas; Air-flow; Posture; Metal-compounds; Metal-fumes; Metal-workers; Metallic-fumes; Ventilation; Humans; Men; Women; Exhaust-ventilation; Particulates
American Industrial Hygiene Conference and Exposition, June 2-7, 2001, New Orleans, Louisiana