Experimental Study on the Performance of a Benchtop Enclosing Hood – Effects of Five Different Face Treatments

Details

• Personal Author:
  Guffey S ; He X ; Lewis B
• Description:
  Benchtop enclosing hoods are used to protect workers from airborne contaminants. Very little has been published on the effectiveness of plain enclosing hoods. Nearly all studies involve lab hoods with sashes. Objective: To compare performance of a 36'x30' enclosing hood with a plain opening to the same hood with external flanges, cowling or sashes attached to the face. Methods: This study was also conducted for three levels (111, 170, and 229 fpm) of hood face velocity and two levels (14 and 46 fpm) of wind tunnel cross-draft velocity combinations with two replications in a factorial design for each treatment: plain, collar flange, bottom flange, cowl, and sash. Freon-134a concentrations were measured on an anthropometrically correct, heated, breathing manikin holding a source between its hands while standing at the enclosing hood face. Samples were taken simultaneously at the nose, mouth, outside the wind tunnel, downstream of the wind tunnel and the exhaust duct. Every location was sampled at 0/15 LPM for 20 minutes. Results: All four interventions significantly (P<0.001) affected the performance of the enclosing hood. Both Flanges and cowl increased the workers exposure dramatically. The sash was the only intervention that improved hood protection efficiency to 100% for all combinations of face velocity and cross-draft velocity. Conclusion: Outside flanges and cowling should not be employed and the sashes are likely to be highly effective in cases where material handling makes them feasible. [Description provided by NIOSH]
• Subjects:
  Air Pollutants, Occupational Laboratories Occupational Health Particulate Matter Safety Ventilation
• Keywords:
  Airborne Particulates Exhaust Hoods Exposure Assessment Laboratory Equipment Ventilation Hoods
• Publisher:
  American Industrial Hygiene Association
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  OSHA Region 3 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  81
• NIOSHTIC Number:
  nn:20070220
• Citation:
  AIHce 2010: American Industrial Hygiene Conference and Exposition, May 22-27, 2010, Denver, Colorado. Falls Church, VA: American Industrial Hygiene Association, 2010 May; :81
• Federal Fiscal Year:
  2010
• Performing Organization:
  West Virginia University
• Peer Reviewed:
  False
• Start Date:
  20050701
• Source Full Name:
  AIHce 2010: American Industrial Hygiene Conference and Exposition, May 22-27, 2010, Denver, Colorado
• End Date:
  20100630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7bcb51eacb1fed3a160e937555a1b69a4570a368b49ebd94bb6aba302ba6e1c6c04c40e2e4ffe5bb046ca9d818cdf40cc8cac76b3109aa9ebb7bbb09691d3797
• Download URL:
  https://stacks.cdc.gov/view/cdc/208473/cdc_208473_DS1.pdf
• File Type:
  [PDF - 1.38 MB ]