Skip directly to search Skip directly to A to Z list Skip directly to page options Skip directly to site content

NIOSHTIC-2 Publications Search

Search Results

Method for measuring the spatial variability of aerosol penetration through respirator filters.

Authors
Huang-C; Willeke-K; Qian-Y; Grinshpun-S; Ulevicius-V
Source
Am Ind Hyg Assoc J 1998 Jul; 59(7):461-465
NIOSHTIC No.
20030556
Abstract
Fibrous filter media are widely used in respirators to remove airborne particulate matter from the inhaled airflow of workers. The N95 half-mask particulate respirator appears to be the most frequently used respirator under the new NIOSH regulation, 42 CFR 84. Considerable spatial variability in light penetration through the fibrous filter medium of an N95 respirator can be seen by visual observation when it is held to the light. This variability is due to the way in which the fibers are manufactured and laid down to form the filter medium. Similar spatial variability is expected in the aerosol penetration through the filters. Therefore, a test method has been developed for measuring the spatial variability in aerosol penetration. The main components of this method are an aerosol generator, a filter test stand with a movable sampling inlet, an aerosol size spectrometer, and an aerosol photometer. Measurements with the filter media of N95 respirators, tested at average filtration velocities corresponding to light, moderate, and heavy work loads, have shown spatial variations in aerosol penetration in excess of 100% relative to the average aerosol penetration for the entire respirator. N95 respirators are required to be at least 95% efficient (i.e., less than 5% penetrating) at the most penetrating particle size, when tested at 85 L/min. Tests with the new method have shown that the aerosol penetration of the most penetrating particles of about 0.1 micron diameter may locally be higher than 5%, while the average aerosol penetration of 0.1 micron particles is less than 5%.
Keywords
Aerosols; Aerosol-particles; Respirators; Respiration; Respiratory-protective-equipment; Filters; Filtration; Air-flow; Air-filters; Airborne-particles; Personal-protection; Personal-protective-equipment; Respiratory-protection; Author Keywords: aerosol penetration; filter medium; respirator; spatial variability
CODEN
AIHAAP
Publication Date
19980701
Document Type
Journal Article
Funding Amount
746102
Funding Type
Grant
Fiscal Year
1998
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-003244
Issue of Publication
7
ISSN
0002-8894
Source Name
American Industrial Hygiene Association Journal
State
OH
Performing Organization
University of Cincinnati, Cincinnati, Ohio
TOP