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Large particle penetration through N95 respirator filters and facepiece leaks with cyclic flow.

Authors
Cho-KJ; Reponen-T; McKay-R; Shukla-R; Haruta-H; Sekar-P; Grinshpun-SA
Source
Ann Occup Hyg 2010 Jan; 54(1):68-77
NIOSHTIC No.
20039937
Abstract
The aim of this study was to investigate respirator filter and faceseal penetration of particles representing bacterial and fungal spore size ranges (0.7-4 mum). First, field experiments were conducted to determine workplace protection factors (WPFs) for a typical N95 filtering facepiece respirator (FFR). These data (average WPF = 515) were then used to position the FFR on a manikin to simulate realistic donning conditions for laboratory experiments. Filter penetration was also measured after the FFR was fully sealed on the manikin face. This value was deducted from the total penetration (obtained from tests with the partially sealed FFR) to determine the faceseal penetration. All manikin experiments were repeated using three sinusoidal breathing flow patterns corresponding to mean inspiratory flow rates of 15, 30, and 85 l min(-1). The faceseal penetration varied from 0.1 to 1.1% and decreased with increasing particle size (P < 0.001) and breathing rate (P < 0.001). The fractions of aerosols penetrating through the faceseal leakage varied from 0.66 to 0.94. In conclusion, even for a well-fitting FFR respirator, most particle penetration occurs through faceseal leakage, which varies with breathing flow rate and particle size.
Keywords
Respirators; Respiratory-function-tests; Respiratory-equipment; Respiratory-protective-equipment; Respiratory-protection; Filters; Particulates; Personal-protective-equipment; Airborne-dusts; Airborne-particles; Author Keywords: cyclic flow; faceseal; filter; penetration; protection factor; respirator
CODEN
AOHYA3
Publication Date
20100101
Document Type
Journal Article
Email Address
tiina.reponen@uc.edu
Funding Type
Grant
Fiscal Year
2010
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-004085
Issue of Publication
1
ISSN
0003-4878
Source Name
Annals of Occupational Hygiene
State
OH
Performing Organization
University of Cincinnati
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