Development of a Thermal Spray Coating Aerosol Generator and Inhalation Exposure System

Details

• Personal Author:
  Afshari AA ; Antonini JM ; Cumpston JB ; Cumpston JL ; Friend S ; Jackson M ; Kodali V ; Lee EG ; Leonard HD ; McKinney W ; Meighan TG
• Description:
  Thermal spray coating involves spraying a product (oftentimes metal) that is melted by extremely high temperatures and then applied under pressure onto a surface. Large amounts of a complex metal aerosol (e.g., Fe, Cr, Ni, Zn) are formed during the process, presenting a potentially serious risk to the operator. Information about the health effects associated with exposure to these aerosols is lacking. Even less is known about the chemical and physical properties of these aerosols. The goal was to develop and test an automated thermal spray coating aerosol generator and inhalation exposure system that would simulate workplace exposures. An electric arc wire-thermal spray coating aerosol generator and exposure system was designed and separated into two areas: (1) an enclosed room where the spray coating occurs; (2) an exposure chamber with different measurement devices and controllers. The physicochemical properties of aerosols generated during electric arc wire-thermal spray coating using five different consumable wires were examined. The metal composition of each was determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), including two stainless-steel wires [PMET720 (82 % Fe, 13 % Cr); PMET731(66 % Fe, 26 % Cr)], two Ni-based wires [PMET876 (55 % Ni, 17 % Cr); PMET885 (97 % Ni)], and one Zn-based wire [PMET540 (99 % Zn)]. The particles generated regardless of composition were poorly soluble, complex metal oxides and mostly arranged as chain-like agglomerates and similar in size distribution as determined by micro-orifice uniform deposit impactor (MOUDI) and electrical low-pressure impactor (ELPI). To allow for continuous, sequential spray coating during a 4-hr exposure period, a motor rotated the metal pipe to be coated in a circular and up-and-down direction. In a pilot animal study, male Sprague-Dawley rats were exposed to aerosols (25 mg/m3 × 4 h/d × 9 d) generated from electric arc wire- thermal spray coating using the stainless-steel PMET720 consumable wire. The targeted exposure chamber concentration was achieved and maintained during a 4-hr period. At 1 d after exposure, lung injury and inflammation were significantly elevated in the group exposed to the thermal spray coating aerosol compared to the air control group. The system was designed and constructed for future animal exposure studies to generate continuous metal spray coating aerosols at a targeted concentration for extended periods of time without interruption. [Description provided by NIOSH]
• Subjects:
  Aerosols Lung Metals Occupational Exposure Occupational Health Particulate Matter Respiratory System Safety Toxicology
• Keywords:
  Aerosol Particles Author Keywords: Thermal Spray Coating Inhalation Studies Inhalation System Lung Irritants Metal Fumes Metal Oxides Occupational Exposure Particle Size Particulates Spraying Operations Sprays

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• ISSN:
  2214-7500
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division ; RHD - Respiratory Health Division
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  126-135
• Volume:
  9
• NIOSHTIC Number:
  nn:20064517
• Citation:
  Toxicol Rep 2022 Jan; 9:126-135
• Contact Point Address:
  James M. Antonini, Centers for Disease Control & Prevention, National Institute for Occupational Safety and Health, Health Effects Laboratory Division, 1000 Frederick Lane (Mailstop 2015), Morgantown, WV 26508, United States
• Email:
  JGA6@cdc.gov
• Federal Fiscal Year:
  2022
• NORA Priority Area:
  Manufacturing ; Services
• Peer Reviewed:
  True
• Source Full Name:
  Toxicology Reports
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:4dd7c96988d7c2975853aa359fd1a85bc90d076b7e57cab9dfd3c8a3394c6a5a2c420828326fd5ff6951429668776a5cb71f6c467d9f4072333d0d922307a9d7
• Download URL:
  https://stacks.cdc.gov/view/cdc/222965/cdc_222965_DS1.pdf
• File Type:
  [PDF - 5.69 MB ]