Ultraviolet Germicidal Irradiation on the New Silicone Half-Piece Elastometric Respirators

Overview

Since the innovation of our new half- elastometric half-piece respirator, this type of FFR has been used widely in our country. Decontamination methods including ultraviolet C (UVC) germicidal irradiation and 70% alcohol have been implemented to decontaminate the respirator. We than examined inactivation potential for the Porcine epidemic diarrhea virus (PEDV), numerous bacterial strains ,mostly skin-derived after the decontamination process.To enable rigorous integrity after repeated decontamination process, fit test by the Bitrex test ,tensile strength and elongation at break were also evaluated. Our results showed that the UVC at the dose of 3 J/cm2 can eradicate the bacteria at 60 min and virus at 10 min.No fungus was found on the mask surface at the beginning. Good Fit test , tensile strength and elongation at break were still main maintained after multiple cycles of decontamination. No evidence of physical degradation by gross visual inspection was found. 70% alcohol is also an easy and effective way to eradicate microorganisms on the mask.As the current pandemic is expected to continue for months to years, the need to supply adequate reserves of PPE and develop effective reprocessing is crucial. Our studies demonstrated that the novel silicone mask can be safely reprocessed and decontaminated for many cycles by UVC irradiation and help restore the shortage of the important protective devices in the COVID-19 pandemic era.

this study showed that UVC irradiation at the dosage 300 uWatt-sec/cm2 for 1 minute satisfactorily decontaminated the silicone mask as measured by viral culture. The timing to eradicate bacteria was 60 minutes longer due to the tolerability of the bacteria .70% alcohol effectively decontaminate the virus and bacteria deposited on the masks and filters. Good level of fit can be maintained following UVC treatment. The tensile strength of the strap was retained over multiple decontamination cycles using UVC and dry heat upto 60 cycles.Given the efficacy of the disinfection by UVC and 70 % alcohol ,these types of decontamination method could potentially be used for the new type of silicone masks half-piece respirator in the setting of a crisis with inadequate supplies of PPE.