Effect of DOP heterodispersion on HEPA-filter-penetration measurements
The accuracy of the standard US test method for certifying High-Efficiency Particulate Air (HEPA) filters has been in question since the finding by Hinds, et al. that the dioctyl phthalate (DOP) aerosol used in the test is not monodisperse as had been assumed and that particle-size analyzers, or owls, could not distinguish between different particle-size distributions with the same owl reading. We have studied theoretically and experimentally the filter efficiency for different DOP size distributions with the same owl reading. Our studies show that the effect of varying DOP size distributions on the measured HEPA-filter penetration depends on the light-scattering-photometer response and on the HEPA-filter penetration curve, both measured as a function of particle size. HEPA-filter penetration for a heterodisperse DOP aerosol may be increased, decreased, or remain the same when compared to the filter penetration for monodisperse aerosols. Using experimental HEPA-filter penetration and photometer response curves, we show that heterodisperse DOP aerosols (D/sub cmd/ 0.19 and sigma g = 1.4) yield 24% lower penetrations than that for monodisperse DOP aerosols (D/sub cmd/ = 0.3 and sigma g = 1.0). This surprisingly small effect of the DOP heterodispersion on HEPA-filter penetration is due to the response function of the owl that is similar to the response of the photometer. Changes in the particle-size distribution are therefore seen in a similar fashion by both the photometer and the owl. We also show that replacing the owl with modern particle-size spectrometers may lead to large errors in filter penetration because the particle-size spectrometers do not provide measurements that correspond to the photometer measurements. 15 references, 16 figures.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6030486
- Report Number(s):
- UCRL-91122; CONF-840806-14; ON: DE85009583
- Resource Relation:
- Conference: 18. DOE nuclear airborne waste management and air cleaning conference, Baltimore, MD, USA, 13 Aug 1984
- Country of Publication:
- United States
- Language:
- English
Similar Records
In-place HEPA filter penetration test
In-place HEPA filter penetration test
Related Subjects
AIR FILTERS
PERFORMANCE TESTING
AEROSOLS
AIR CLEANING
COMPARATIVE EVALUATIONS
EXPERIMENTAL DATA
PARTICULATES
PHOTOMETERS
SIZE
SPECTROMETERS
CLEANING
COLLOIDS
DATA
DISPERSIONS
EQUIPMENT
FILTERS
INFORMATION
MEASURING INSTRUMENTS
NUMERICAL DATA
PARTICLES
POLLUTION CONTROL EQUIPMENT
SOLS
TESTING
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)