Development of an inhalation exposure system for resistance spot welding using an anti-spatter spray

Details

• Personal Author:
  Afshari A ; Antonini JM ; Chen BT ; Cumpston A ; Cumpston J ; Frazer DG ; Jackson M ; Leonard HD ; McKinney W ; Schwegler-Berry D ; Zeidler-Erdely PC
• Description:
  A common metal joining process is resistance spot welding (RSW). In RSW, two copper alloy electrodes squeeze pieces of sheet metal together and pass high levels of current through the metals to create a weld. The process generates a complex aerosol. The chemical properties of the aerosol are dependent on the metal profile of the welded sheet metal as well as the composition of anti-spatter agents used during the process. Anti-spatter treatment protects the electrodes and improves the welding surface finish. However, anti-spatter chemicals contain ingredients known to be harmful to health. Respiratory disease has been observed in RSW welders. The goal was to design an RSW inhalation exposure system that includes an anti-spatter spray system and determine if the anti-spatter agent contributes to lung responses associated with RSW fume. This system will be used for animal toxicology studies. The system is divided into different areas: (1) enclosed automated spot welder; (2) exposure chamber with aerosol characterization equipment; (3) sheet metal driving system; (4) computer control room and (5) anti-spatter spray unit. The anti-spatter agent was sprayed before welding on the surface of two strips of low carbon steel. A fume injector was used that is controlled by a data acquisition system. Generated RSW fume was delivered to the animal exposure chamber. A real-time aerosol monitor was used to measure and maintain a RSW particle mass concentration of 25 mg/m3. SEM/EDX revealed the RSW aerosols to be primarily composed of iron and arranged as chain-like agglomerates. Analysis of the size distribution indicated the MMAD of the generated particles was approximately 0.258 microm. Two distinct particle morphologies were observed; a reddish-brown metal particle (likely iron) observed in the nanometer size range and a yellowish particle in the larger micron/submicron range (likely from anti-spatter agent). The exposure system has been designed to assess the potential toxicity of anti-spatter spray used in RSW. [Description provided by NIOSH]
• Subjects:
  Aerosols Chemistry Electricity Environmental Monitoring Inhalation Exposure Laboratories Metals Occupational Health Particulate Matter Respiratory Tract Diseases Safety Toxicology Welding

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• Keywords:
  Aerosol-dispensers Aerosol-generators Chemical-composition Dose-response Electrical-conductivity Exposure-assessment Inhalants Laboratory-animals Laboratory-testing Metal-compounds Metal-finishing Metal-fumes Morphology Nanotechnology Particulates Respiratory-system-disorders Sprays Welders-lung

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• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• Place as Subject:
  California ; OSHA Region 3 ; OSHA Region 9 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  144
• Issue:
  1
• NIOSHTIC Number:
  nn:20045983
• Citation:
  Toxicologist 2015 Mar; 144(1):338
• CAS Registry Number:
  Iron (CAS RN 7439-89-6)
• Federal Fiscal Year:
  2015
• NORA Priority Area:
  Construction
• Peer Reviewed:
  False
• Source Full Name:
  The Toxicologist. Society of Toxicology 54th Annual Meeting and ToxExpo, March 22-26, 2015, San Diego, California
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:f1cfc2c7746a73b91f6258c04bfb6a65dbfbbad405094e3f488a53324108d5917e6c9bfe5fc224a669d71ad00b43c863097784f5f7dc33f280cd0b4aca5f0d18
• Download URL:
  https://stacks.cdc.gov/view/cdc/201182/cdc_201182_DS1.pdf
• File Type:
  [PDF - 218.32 KB ]