Correlation of Penetration Results Between Filter Testers that Use Different Particle Generators and Detection Methods, 1998 Nonwovens Conference Proceedings

Efficiency results obtained by a filter tester will depend on the aerosol size distribution and the properties of the particle detector. Results of different test methods can be related by analyzing the side distribution of the aerosol and relating that to how the particle detector detects particles. Some aerosol generators produce polydisperse aerosols and others produce monodisperse aerosol with varying degrees of monodispersity. Small changes in either the median size or the width of the distribution (geometric standard deviation) can have large affects on the efficiency results. Some particles detectors count particles while others measure the amount of light scattered by the particles. These different techniques also result in different efficiency results.

The size distribution of a test aerosol can be determined by using a SMPS scanning mobility particle sizer). The efficiency curve for the filter can be determined by doing a filter efficiency test using monodisperse test aerosol. Using the properties of the particle detector it is possible to determine the efficiency that will result using various detectors. This paper shows the results of this analysis and compares the predicted results with test result data from different automated filter testers and different test aerosols.