A method to determine the available UV-C dose for the decontamination of filtering facepiece respirators
Article first published online: 4 NOV 2010
Journal of Applied Microbiology © 2010 The Society for Applied Microbiology. No claim to US Government works
Journal of Applied Microbiology
Volume 110, Issue 1, pages 287–295, January 2011
How to Cite
Fisher, E.M. and Shaffer, R.E. (2011), A method to determine the available UV-C dose for the decontamination of filtering facepiece respirators. Journal of Applied Microbiology, 110: 287–295. doi: 10.1111/j.1365-2672.2010.04881.x
- Issue published online: 10 DEC 2010
- Article first published online: 4 NOV 2010
- Accepted manuscript online: 8 OCT 2010 10:40PM EST
- 2009/1758: received 6 October 2009, revised 25 June 2010 and accepted 30 September 2010
- filtering facepiece respirator;
Aims: To develop a method to assess model-specific parameters for ultraviolet-C (UV-C, 254 nm) decontamination of filtering facepiece respirators (FFRs).
Methods and Results: UV-C transmittance was quantified for the distinct composite layers of six N95 FFR models and used to calculate model-specific α-values, the percentage of the surface UV-C irradiance available for the internal filtering medium (IFM). Circular coupons, excised from the FFRs, were exposed to aerosolized particles containing MS2 coliphage and treated with IFM-specific UV-C doses ranging from 38 to 4707 J m−2. Models exposed to a minimum IFM dose of 1000 J m−2 demonstrated at least a 3 log reduction (LR) in viable MS2. Model-specific exposure times to achieve this IFM dose ranged from 2 to 266 min.
Conclusions: UV-C transmits into and through FFR materials. LR of MS2 was a function of model-specific IFM UV-C doses.
Significance and Impact of the Study: Filtering facepiece respirators are in high demand during infectious disease outbreaks, potentially leading to supply shortages. Reuse of disposable FFRs after decontamination has been discussed as a possible remediation strategy, but to date lacks supporting scientific evidence. The methods described here can be used to assess the likelihood that UV-C decontamination will be successful for specific FFR models.