Infrared imaging for leak detection of N95 filtering facepiece respirators: a pilot study.

BACKGROUND This study was undertaken to determine the utility of an infrared camera (IRC) for assessing leaks around filtering facepiece respirators (FFR) during quantitative respirator fit testing. METHODS Eight subjects underwent quantitative fit testing on six N95 FFR models (48 total fit tests) while simultaneously being recorded with an IRC. RESULTS The IRC detected 49 exhalation leaks during 39 tests and no leaks in nine tests. Exhalation leaks were identified in all failed fit tests (13) and a majority (26 of 35) of passed tests. Anatomically, the nasal region and malar (cheekbone) regions accounted for 71% of identified leak sites. Fit factors for fit tests without identified exhalation leaks were significantly higher than fit tests with leaks detected by IRC (P = 0.01). CONCLUSIONS Thermal imaging using IRC can detect leaks in respiratory protective equipment and has the potential as a screening tool for assessment of the adequacy of post-donning FFR fit.

[1]  C. Knapp,et al.  Health care workers' views about respirator use and features that should be included in the next generation of respirators , 2009, American Journal of Infection Control.

[2]  A Sreenath,et al.  A modified protocol for quantitative fit testing using the PortaCount. , 2001, Applied occupational and environmental hygiene.

[3]  Ziqing Zhuang,et al.  Correlation Between Respirator Fit and Respirator Fit Test Panel Cells by Respirator Size , 2008, Journal of occupational and environmental hygiene.

[4]  Dennis J. Viscusi,et al.  Impact of Three Biological Decontamination Methods on Filtering Facepiece Respirator Fit, Odor, Comfort, and Donning Ease , 2011, Journal of occupational and environmental hygiene.

[5]  Jeffrey B. Powell,et al.  Effect of exhaled moisture on breathing resistance of N95 filtering facepiece respirators. , 2010, The Annals of occupational hygiene.

[6]  R K Oestenstad,et al.  Distribution of faceseal leak sites on a half-mask respirator and their association with facial dimensions. , 1990, American Industrial Hygiene Association journal.

[7]  P. McCarthy,et al.  Thermal screening of facial skin arterial hot spots using non-contact infrared radiometry , 2008, Physiological measurement.

[8]  Bryan F. Jones,et al.  A reappraisal of the use of infrared thermal image analysis in medicine , 1998, IEEE Transactions on Medical Imaging.

[9]  Don-Hee Han,et al.  Evaluation of particulate filtering respirators using inward leakage (IL) or total inward leakage (TIL) testing--Korean experience. , 2005, The Annals of occupational hygiene.

[10]  Paul A. Jensen,et al.  Reducing Respirator Fit Test Errors: A Multi-Donning Approach , 2005 .

[11]  S. Lam,et al.  Sensitivity and specificity of the user-seal-check in determining the fit of N95 respirators , 2011, Journal of Hospital Infection.

[12]  Filippo Molinari,et al.  Noise Estimation in Infrared Image Sequences: A Tool for the Quantitative Evaluation of the Effectiveness of Registration Algorithms , 2008, IEEE Transactions on Biomedical Engineering.

[13]  K. Dubowski.  Studies in breath-alcohol analysis: Biological factors , 1975, Zeitschrift für Rechtsmedizin.

[14]  E.Y.K. Ng,et al.  Study of facial skin and aural temperature , 2006, IEEE Engineering in Medicine and Biology Magazine.

[15]  T. Chau,et al.  Infrared thermography as an access pathway for individuals with severe motor impairments , 2009, Journal of NeuroEngineering and Rehabilitation.

[16]  Mike Clayton,et al.  Fit for purpose? The role of fit testing in respiratory protection. , 2005, The Annals of occupational hygiene.

[17]  D. Musher.  How contagious are common respiratory tract infections? , 2003, The New England journal of medicine.

[18]  J. Steketee.  Spectral emissivity of skin and pericardium. , 1973, Physics in medicine and biology.

[19]  J L Derrick,et al.  Predictive value of the user seal check in determining half-face respirator fit , 2004, Journal of Hospital Infection.

[20]  M. Buono,et al.  Comparison of infrared versus contact thermometry for measuring skin temperature during exercise in the heat , 2007, Physiological measurement.

[21]  T. Conine,et al.  Assessment of an infra-red non-contact sensor for routine skin temperature monitoring: a preliminary study. , 1992, Journal of medical engineering & technology.

[22]  Tiina Reponen,et al.  Laboratory and field evaluation of a new personal sampling system for assessing the protection provided by the N95 filtering facepiece respirators against particles. , 2005, The Annals of occupational hygiene.

[23]  I. Pavlidis,et al.  Noncontact measurement of breathing function , 2006, IEEE Engineering in Medicine and Biology Magazine.

[24]  Jan Rustemeyer,et al.  Thermography and thermoregulation of the face , 2007, Head & face medicine.

[25]  Riedar Kent Oestenstad,et al.  Factors Affecting the Location and Shape of Face Seal Leak Sites on Half-Mask Respirators , 2010, Journal of occupational and environmental hygiene.

[26]  Lisa M Brosseau,et al.  Surgical mask filter and fit performance , 2008, American Journal of Infection Control.

[27]  Jonathan B. Dowdall,et al.  Thermal image analysis for detecting facemask leakage , 2005, SPIE Defense + Commercial Sensing.

[28]  A. Jones.  Quantitative measurements of the alcohol concentration and the temperature of breath during a prolonged exhalation. , 1982, Acta physiologica Scandinavica.