Use of tracer gas technique for industrial exhaust hood efficiency evaluation - where to sample?

Details

• Personal Author:
  Bartley, David L. ; Hampl V ; Niemela R ; Shulman S
• Description:
  A tracer gas method employing sulfur-hexafluoride (SF6) was developed to estimate the efficiency of industrial exhaust hoods controlling gaseous and vaporous emissions, and a study was performed to determine the minimum sampling distance from the exhaust hood at which the sampling probe should be located to minimize error caused by the nonhomogeneous dispersion of SF6 in the duct. SF6 was measured with a gas chromatograph equipped with an electron capture detector. It was found that the sampling probe should be located in the straight duct at a minimum distance of approximately 50 duct diameters, where SF6 was considered to be dispersed uniformly across the duct cross section, and sampling could be conducted at any depth in the duct. With a straight duct side branch combination, the SF6 dispersion was somewhat accelerated and the minimum sampling distance was reduced to 25 and 40 duct diameters at Reynolds numbers of 120,000 and 200,000, respectively. For a straight duct with one elbow, the minimum distance was significantly reduced to 7 duct diameters. When two elbows were present, a minimum distance of approximately 4 duct diameters was found. [Description provided by NIOSH]
• Subjects:
  Environmental Monitoring Hazardous Substances Occupational Health Safety Ventilation
• Keywords:
  Air-monitoring Air-sampling-techniques Analytical-methods Exhaust-hoods Industrial-hygiene NIOSH-Author Pollutants Quantitative-analysis Toxic-vapors
• ISSN:
  0002-8894
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DPSE - Division of Physical Sciences and Engineering
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  281-287
• Volume:
  47
• Issue:
  5
• NIOSHTIC Number:
  nn:00166471
• Citation:
  Am Ind Hyg Assoc J 1986 May; 47(5):281-287
• Contact Point Address:
  Vladimir Hampl, National Institute for Occupational Safety and Health, Division of Physical Sciences and Engineering, 4676 Columbia Parkway, Cincinnati, OH 45226
• Federal Fiscal Year:
  1986
• Peer Reviewed:
  True
• Source Full Name:
  American Industrial Hygiene Association Journal
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:52ce69062d6f269acf794c6a8d0d8e94537d27d83b0b19c0dd2c93ea144b511f59ef2015f3cc363a836218fcb5e92317954eb3b2dbdb81b15e4c58a5f0f05574
• Download URL:
  https://stacks.cdc.gov/view/cdc/185107/cdc_185107_DS1.pdf
• File Type:
  [PDF - 599.44 KB ]