Distribution of faceseal leak sites on a half-mask respirator and their association with facial dimensions.
Oestenstad-RK; Dillion-HK; Perkins-LL
Am Ind Hyg Assoc J 1990 May; 51(5):285-290
The distribution of faceseal leak sites on a half mask respirator and their association with facial dimensions were examined. The cohort consisted of 73 volunteers, 39 males, mean age 30.6 years. Twelve parameters that characterized facial dimensions were measured on each subject. The subjects were fitted with a United States Series 200 half mask respirator. A quantitative fit test was performed using standard criteria. The subjects were exposed to a fluorescent tracer aerosol. Faceseal leaks were identified from where the tracer deposited inside the mask. The leaks were classified according to their location and shape. The association of leak sites and facial dimensions was examined by regression techniques. A total of 110 leaks were detected. Of these, 89% occurred at the nose or chin or were multiple leaks that included these sites. Fit factors for subjects with nose plus chin and chin leaks were significantly lower than for subjects who did not have these leaks. The distribution of leak sites was similar for males and females. Approximately 73% of the leaks resembled a slit and the rest a round orifice. Females experienced fewer diffuse leaks. Only two facial dimensions, subnasale/nasion length and lip width, were not significantly associated with leak sites. Approximately 71% of the association between facial dimensions and leak site could be attributed to gender differences. Evidence of airflow streamlining within the face piece was noted in 16 subjects. The authors conclude that leaks at the nose and chin are the most important factors affecting faceseal leaking in this type of respirator. Respirators designed for male faces may not fit females very well. Face length and lip width may not be appropriate criteria for selecting respirators or predicting respirator leakage.
NIOSH-Publication; NIOSH-Grant; Respirators; Leak-detectors; Laboratory-testing; Respiratory-protective-equipment; Equipment-reliability; Industrial-hygiene; Anthropometry; Sex-factors; Statistical-analysis; Mathematical-models
Environmental Health Sciences Univ. of Alabama at Birmingham School of Public Health Birmingham, AL 35294
American Industrial Hygiene Association Journal
University of Alabama at Birmingham, Birmingham, Alabama