Efficiency of Intact and Damaged HEPA Filters and Their Gaskets Under Different Flowrate and Pressure Drop Conditions

Details

• Personal Author:
  Akbar-Khanzadeh F ; Smigielski K
• Description:
  Objective: High efficiency particulate air (HEPA) filter, a main element of industrial or domestic ventilation systems, can be damaged during handling and installation. Then, the question is how the damage would alter the performance of the filter. This project was to evaluate HEPA filter capture efficiency of intact or damaged gaskets and filters. Methods: The filters (60 x 60 x 29 cm) for: (a) "gasket testing" used PTFE with one piece poured gasket; and, (b) "filter testing" used glass fiber, with a dove tail gasket. Poly Alpha Olefin particulate was used as aerosol challenge. Aerosol generators with specific nozzles were to generate known diameter (e.g., 0.3 um) particles. A counter instrument was used to count the particles at the inlet and outlet of a custom designed filter housing. Each finally reported count was an average of 6 readings. Known diameter holes to the gasket and filter were created by using a set of standard cylinders. The gaskets and filters were tested within the filter housing at two system airflows (28.3x103 and 56.6x103 L/min) and two pressure drops (25 and 50 mm water gauge). Gaskets and filters were tested under following conditions: (1) best fit: no known gasket or filter leak, and (2) man-made holes: gaskets and filters with 6 sizes man-made holes of 0.5, 0.8, 1.6, 3.2, 4.8 and 6.4 mm diameters. Results: The best fit HEPA filter performed at capture efficiency of more than 99.99%. Particle leakage increased with the diameter of hole. However, at 0.5, 0.8 and 1.6 mm diameter holes the capture efficiency remained above 99.99%. At 3.2 mm hole the efficiency dropped to 99.98% and at 4.8 and 6.4 mm holes the capture efficiency dropped below the HEPA quality capture efficiency of 99.97%. Conclusions: The capture efficiency of HEPA filters remained above 99.97% at or smaller than 3.2 mm hole in either gasket or filter media. Additional tests are recommended to further verify these findings. [Description provided by NIOSH]
• Subjects:
  Air Pollutants, Occupational Occupational Health Particulate Matter Safety Ventilation
• Keywords:
  Airborne Particulates Air Filters Filter Materials HEPA Filters High-efficiency Particulate Air Filters
• Publisher:
  American Industrial Hygiene Association
• Document Type:
  Text
• Funding:
  Grant
• Genre:
  Abstract or Summary
• Place as Subject:
  Ohio ; OSHA Region 5
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  10
• NIOSHTIC Number:
  nn:20054440
• Citation:
  AIHce 2015: American Industrial Hygiene Conference and Exposition, May 30 - June 4, 2015, Salt Lake City, Utah. Falls Church, VA: American Industrial Hygiene Association, 2015 Jun; :10
• Federal Fiscal Year:
  2015
• Performing Organization:
  University of Toledo Health Science Campus, Ohio
• Peer Reviewed:
  False
• Start Date:
  20050701
• Source Full Name:
  AIHce 2015: American Industrial Hygiene Conference and Exposition, May 30 - June 4, 2015, Salt Lake City, Utah
• End Date:
  20250630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7fa51d4a9384c893feb7f19f5a4041ba26605729252a3c07080c783c8dfa98efea782603cf9ed9129475f4fe31805affecf06e4e4ceae6c6639ea4aace898b43
• Download URL:
  https://stacks.cdc.gov/view/cdc/217006/cdc_217006_DS1.pdf
• File Type:
  [PDF - 673.36 KB ]