Hard Metal Exposures. Part 1: Observed Performance of Three Local Exhaust Ventilation Systems

Details

• Personal Author:
  Booth DW Sr. ; Guffey SE ; Hibbard R ; Simcox N ; Stebbins A
• Description:
  Not every ventilation system performs as intended; much can be learned when they do not. The purpose of this study was to compare observed initial performance to expected levels for three saw-reconditioning shop ventilation systems and to characterize the changes in performance of the systems over a one-year period. These three local exhaust ventilation systems were intended to control worker exposures to cobalt, cadmium, and chromium during wet grinding, dry grinding, and welding/brazing activities. Prior to installation the authors provided some design guidance based on Industrial Ventilation, a Manual of Recommended Practice. However, the authors had limited influence on the actual installation and operation and no line authority for the systems. In apparent efforts to cut costs and to respond to other perceived needs, the installed systems deviated from the specifications used in pressure calculations in many important aspects, including adding branch ducts, use of flexible ducts, the choice of fans, and the construction of some hoods. After installation of the three systems, ventilation measurements were taken to determine if the systems met design specifications, and worker exposures were measured to determine effectiveness. The results of the latter will be published as a companion article. The deviations from design and maintenance failures may have adversely affected performance. From the beginning to the end of the study period the distribution of air flow never matched the design specifications for the systems. The observed air flows measured within the first month of installation did not match the predicated design air flows for any of the systems, probably because of the differences between the design and the installed system. Over the first year of operation, hood air flow variability was high due to inadequate cleaning of the sticky process materials which rapidly accumulated in the branch ducts. Poor distribution of air flows among branch ducts frequently produced individual hood air flows that were far below specified design levels even when the total air flow through that system was more than adequate. To experienced practitioners, it is not surprising that deviations from design recommendations and poor maintenance would be associated with poor system performance. Although commonplace, such experiences have not been documented in peer-reviewed publications to date. This publication is a first step in providing that documentation. [Description provided by NIOSH]
• Subjects:
  Air Movements Air Pollutants, Occupational Cadmium Metals Occupational Health Safety Ventilation
• Keywords:
  Airborne Particles Air Contamination Air Flow Author Keywords: Intervention Research Cadmium Compounds Cobalt Cobalt Compounds Exhaust Systems Exhaust Ventilation Hard Metal Hard Metals Industrial Ventilation Metal Compounds Metal Exposures Stellite Tungsten Carbide Ventilation Systems

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• ISSN:
  1047-322X
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Journal Article
• Place as Subject:
  California ; OSHA Region 10 ; OSHA Region 9 ; Washington
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  331-341
• Volume:
  15
• Issue:
  4
• NIOSHTIC Number:
  nn:20029827
• Citation:
  Appl Occup Environ Hyg 2000 Apr; 15(4):331-341
• Contact Point Address:
  School of Public Health and Community Medicine, University of Washington, Seattle, Washington
• Federal Fiscal Year:
  2000
• NORA Priority Area:
  Research Tools and Approaches: Intervention Effectiveness Research
• Performing Organization:
  University of Washington, Department of Environmental Health, Seattle, WA
• Peer Reviewed:
  True
• Start Date:
  19940401
• Source Full Name:
  Applied Occupational and Environmental Hygiene
• End Date:
  19971030
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:18dec764da7864a1e7d9929989f55986598d572adb8efffb49950ee4b3e61584de6f366b33c26f7e74befef6567024e21fd5b33898f0b87cf2ffc51b38ac3d63
• Download URL:
  https://stacks.cdc.gov/view/cdc/190732/cdc_190732_DS1.pdf
• File Type:
  [PDF - 390.33 KB ]