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Particle Size for Greatest Penetration of HEPA Filters - and Their True Efficiency.

DE83008439

Publication Date	1982
Personal Author	da Roza, R. A.
Page Count	17
Abstract	The particle size that most greatly penetrates a filter is a function of filter media construction, aerosol density, and air velocity. In this paper the published results of several experiments are compared with a modern filtration theory that predicts single-fiber efficiency and the particle size of maximum penetration. For high-efficiency particulate air (HEPA) filters used under design conditions this size is calculated to be 0.21 mu m diam. This is in good agreement with the experimental data. The penetration at 0.21 mu m is calculated to be seven times greater than at the 0.3 mu m used for testing HEPA filters. Several mechanisms by which filters may have a lower efficiency in use than when tested are discussed. (ERA citation 08:024244)
Keywords	Filters Aerosols Radioactive aerosols Air pollution Filtration Air pollution control Particle size Density Velocity Efficiency Comparative evaluations Reviews ERDA/500200 ERDA/500300
Source Agency	Technical Information Center Oak Ridge Tennessee
NTIS Subject Category	68A - Air Pollution & Control 68F - Radiation Pollution & Control
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Portions are illegible in microfiche products. Original copy available until stock is exhausted.
Document Type	Technical Report
NTIS Issue Number	198317
Contract Number	W-7405-ENG-48

Particle Size for Greatest Penetration of HEPA Filters - and Their True Efficiency.

Particle Size for Greatest Penetration of HEPA Filters - and Their True Efficiency.
DE83008439

Publication Date	1982
Personal Author	da Roza, R. A.
Page Count	17
Abstract	The particle size that most greatly penetrates a filter is a function of filter media construction, aerosol density, and air velocity. In this paper the published results of several experiments are compared with a modern filtration theory that predicts single-fiber efficiency and the particle size of maximum penetration. For high-efficiency particulate air (HEPA) filters used under design conditions this size is calculated to be 0.21 mu m diam. This is in good agreement with the experimental data. The penetration at 0.21 mu m is calculated to be seven times greater than at the 0.3 mu m used for testing HEPA filters. Several mechanisms by which filters may have a lower efficiency in use than when tested are discussed. (ERA citation 08:024244)
Keywords	Filters Aerosols Radioactive aerosols Air pollution Filtration Air pollution control Particle size Density Velocity Efficiency Comparative evaluations Reviews ERDA/500200 ERDA/500300
Source Agency	Technical Information Center Oak Ridge Tennessee
NTIS Subject Category	68A - Air Pollution & Control 68F - Radiation Pollution & Control
Corporate Authors	Lawrence Livermore National Lab., CA.; Department of Energy, Washington, DC.
Supplemental Notes	Portions are illegible in microfiche products. Original copy available until stock is exhausted.
Document Type	Technical Report
NTIS Issue Number	198317
Contract Number	W-7405-ENG-48