The report gives results of an evaluation of the influence of five fiber parameters (cross-sectional shape, linear density, surface roughness, crimp, and staple length) on the filtration performance of model nonwoven fabrics made from the fibers. Nonwoven fabrics made from 32 polyester fiber samples were used to filter fly-ash particles from a stream of air. Filter performance was assessed by measuring: pressure drop across the filter, collection efficiency, and particle size distribution. Efficiency was improved by using trilobal (rather than round cross-section) fibers with no detrimental effect on drag; efficiency and drag were improved by using crimped (rather than uncrimped) fibers; and efficiency was improved by using 3 (rather than 6) denier fibers, but at the cost of greater drag. These efficiency improvements were especially pronounced for fine particles (approximately 2.5 microns). Rougher fibers appeared more efficient in removing fine particles. Applying d.c. voltages to 100% non-conducting polyester filters showed considerable increases in efficiency.

Prepared by Textile Research Institute, Princeton, N.J. for U.S. Environmental Protection Agency, Office of Research and Development, Control Systems Laboratory, National Environmental Research Center, Research Triangle Park, N.C. under Contract no. R-800042, Program Element no. 1AB012: ROAP no. 21ADL-022. "EPA-650/2-75-002." "January 1975."