Using a Filter Bypass Leakage Test for Aerosol Sampling Cassettes

Details

• Personal Author:
  Baron, Paul A.
• Description:
  The plastic two- and three-piece cassettes commonly used for collection of personal samples of airborne dust may be prone to bypass leakage if the cassettes are not properly assembled. The filter is clamped into place in the cassette by pressing together the base and the ring or cap of the cassette. If pressure is insufficient, or the base and mating piece are not aligned properly, air can flow through the inside of the cassette and around the filter (see Figure 1).(1) If too much pressure is used, the cassette can crack, also producing bypass leakage. This air flow can carry particles and con- tribute to loss of the particle mass that should have been collected on the filter, thus resulting in an underestimate of worker exposure. Press-fitted cassettes continue to be widely used. Anecdotal indications of leakage have cropped up from time to time, but the issue has not been dealt with satisfactorily. Van den Reever and Tieman(2) presented data on cassettes using a pressure drop measurement to indicate leakage. The average pressure drop for a specific cassette/filter combination was measured for a number of "good" cassettes; any decreased pressure drop observed for the assembled cassettes was attributed to bypass leakage. l Establishment of this baseline pressure drop when assembling only a few cassettes has been cumbersome, and a more direct measure of leakage is deemed. [Description provided by NIOSH]
• Subjects:
  Aerosols Dust Environmental Monitoring Occupational Health Respiratory Function Tests Safety
• Keywords:
  Aerosol-sampling Air-samplers Air-sampling-techniques Dust-collection Respiratory-function-tests
• ISSN:
  1047-322X
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  DART - Division of Applied Research and Technology
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  17
• Issue:
  9
• NIOSHTIC Number:
  nn:20022220
• Citation:
  Appl Occup Environ Hyg 2002 Sep; 17(9):593-597
• Contact Point Address:
  NIOSH, 4676 COlumbia Parkway, Cincinnati, OH 45226
• Editor(s):
  Tharr D
• Federal Fiscal Year:
  2002
• NORA Priority Area:
  Research Tools and Approaches: Exposure Assessment Methods
• Peer Reviewed:
  True
• Source Full Name:
  Applied Occupational and Environmental Hygiene
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7ebb74c15813e7bbbcb1f2d8fcb7909db01b009b6a513a57fdfccbdd7eac498a8e3b03318176197da556e5707ee54720c2317317c603df19588d8afa078d224d
• Download URL:
  https://stacks.cdc.gov/view/cdc/199075/cdc_199075_DS1.pdf
• File Type:
  [PDF - 312.80 KB ]