Characterization of different consumable wires in a novel thermal spray coating aerosol generator and inhalation exposure system.

Details

• Personal Author:
  Afshari A ; Allen C ; Antonini JM ; Cumpston JB ; Cumpston JL ; Friend S ; Jackson M ; Kodali V ; Lee EG ; Leonard HD ; McKinney W ; Meighan TG
• Description:
  Thermal spray coating (TSC) involves spraying a metal coating product that is melted by extremely high temperatures and then applied under air pressure onto a surface. Large amounts of a complex metal aerosol comprised of Fe, Cr, Ni, and Zn are formed during the process, presenting a potentially serious risk to the operator. Information about the health effects associated with exposure to aerosols generated during TSC is lacking. Even less is known about the chemical and physical properties of these aerosols. The goal was to construct and characterize an automated TSC aerosol generator and inhalation exposure system that would simulate workplace exposures. An electric arc wire-TSC aerosol generator and exposure system was designed and separated into two areas: (A) an enclosed room with a closed spray booth where the spray coating occurred; (B) an exposure chamber with different particle characterization devices. The physicochemical properties of aerosols generated during electric arc wire-TSC using five different consumable wires were examined. The metal composition of each was determined by 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 generated particles, regardless of composition, were poorly soluble, complex metal oxides and mostly arranged as chain-like agglomerates of primary particles in the ultrafine range (<100 nm). The MMAD as determined by a MOUDI was similar when comparing the generated particles from the different wires and ranged from 290-378 nm. To allow for continuous, sequential coating within the spray booth during a 2-hr testing period, a motor rotated the metal feedstock pipe to be coated in a circular and up-and-down direction. The spray gun was controlled by computer software and fired at programmed 1-sec intervals for up to a total of 12 sprays during the testing period. A targeted exposure chamber concentration of 25 mg/m3 was achieved and maintained during the 2-hr period, along with minimal fluctuations in relative humidity, temperature, and CO2 levels. This exposure system will generate continuous, controlled metal spray coating aerosols for future animal exposure studies. [Description provided by NIOSH]
• Subjects:
  Aerosols Metals Occupational Health Safety Toxicology
• Keywords:
  Toxicology; Spraying operations; Sprays; Metals; Metal fumes; Aerosols; Aerosol particles; Exposure assessment; Metal oxides
• ISSN:
  1096-6080
• Document Type:
  Text
• Genre:
  Abstract or Summary
• 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:
  88
• Volume:
  186
• NIOSHTIC Number:
  nn:20064924
• Citation:
  Toxicologist 2022 Mar; 186(S1):88
• CAS Registry Number:
  Chromium (CAS RN 7440-47-3) ; Iron (CAS RN 7439-89-6) ; Nickel (CAS RN 7440-02-0) ; Silica (CAS RN 7631-86-9) ; Zinc (CAS RN 7440-66-6)
• Federal Fiscal Year:
  2022
• NORA Priority Area:
  Manufacturing
• Peer Reviewed:
  False
• Source Full Name:
  The Toxicologist. Society of Toxicology 61st Annual Meeting & ToxExpo, March 27-31, 2022, San Diego, California
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:865da08254eb1c078ea18c0b3f2c9ef868dbefc76fb4539d5957460bab57c225e5343829b3900d6322fb138c545e5468fb504b4c9d3d8ef316596c0a735392f2
• Download URL:
  https://stacks.cdc.gov/view/cdc/248764/cdc_248764_DS1.pdf
• File Type:
  [PDF - 240.29 KB ]