A Practical Approach to Filtering Facepiece Respirator Decontamination and Reuse: Ultraviolet Germicidal Irradiation

Ultraviolet germicidal irradiation of influenza-contaminated N95 filtering facepiece respirators

Beyond an exceptional human toll, one of the most evident impacts of the ongoing COVID-19 pandemic is that of disrupted supply chain dynamics. Lessons learned here might help ameliorate the ability of frontline workers to secure personal protective equipment (PPE) such as N95 filtering facepiece respirators (FFRs) to prevent similar issues in future pandemics. A related concern is FFR waste streams, and the ability to recycle N95s using chemical or physical germicidal methods would greatly contribute to lessening PPE scarcity and providing relief to overall supply chains for all essential services. Early in 2020, the U.S. Food and Drug Administration (FDA) issued official guidance for sterilizers, disinfectant devices, and air purifiers with regards to the COVID-19 pandemic as a public health emergency bulletin. This guidance provided nonbinding recommendations for PPE and FFR decontamination processes, involving a wide spectrum of chemical and physical methods of sterilization. Many of the sterilization methods employ high heat or utilize polar chemical disinfectants that can compromise either the physical structure or the electrostatic properties of FFR fibers, thus attenuating the overall protection provided to the frontline worker. Ultraviolet germicidal irradiation (UVGI) has been employed for nearly a century to sterilize instruments and whole environments. UVGI offers numerous advantages as it is transitory by nature, leaving no chemical residue on the treated artifact. UVGI is also rapid, and depending on illumination sources, UVGI can easily scale to provide coverage to large areas. Here we provide an analysis of the regulatory aspect related to the use of UVC devices and describe our engineered design of a cost-efficient sterilization chamber that utilizes UVC for decontamination. Our design stresses a low-cost price point to facilitate easy manufacture for not only rapid deployment but also minimal impacts on supply chains. The device is intended to be easy to use, without any specialized training, and thus targets the general public for sanitizing non-washable materials, including PPE, FFR and other potential fomites, including electronic devices of daily use, that otherwise might harbor bacterial, viral and fungal pathogens.

Face mask decontamination and reuse: Is it ok?

Evaluating an Ultraviolet C System for Use During SARS-CoV2 Pandemic and Personal Protective Equipment Shortage

The importance of fit testing in decontamination of N95 respirators: A cautionary note

During the COVID-19 pandemic, shortages of filtering facepiece respirators (FFRs), including N95 masks, highlighted the critical need for effective decontamination and reuse strategies. Current decontamination methods often rely on large, expensive equipment, hindering point-of-care application and timely reprocessing. This study presents the design and evaluation of a portable, low-cost system utilizing high-voltage pulsed electric fields (PEF) for FFR sterilization and electrostatic recharge. A novel PEF generator was developed, featuring precise control over pulse parameters and significantly faster rise/fall times compared to existing systems. The generator was integrated into a compact, user-friendly enclosure with custom-designed electrodes. Testing demonstrated that PEF treatment did not compromise N95 mask filtration efficacy, as confirmed by Bacterial Filtration Efficiency (BFE) and Differential Pressure (Delta P) testing conducted by Nelson Labs. Furthermore, in collaboration with the Mayo Clinic, the system's efficacy against SARS-CoV-2 inoculated onto FFR fabric was evaluated. Results showed significant reduction in viral load after PEF treatment short of complete inactivation, comparable to or exceeding the efficacy of traditional sterilization methods but with significantly shorter treatment times. This portable PEF system offers a promising solution for rapid, efficient, and cost-effective FFR decontamination and reuse, potentially mitigating PPE shortages and reducing healthcare costs and waste.Clinical Relevance- During the coronavirus disease-2019 (COVID-19) pandemic, PPE, including filtering facepiece respirators (FFRs), were critical to contain disease spread and protect first responders and healthcare workers on the frontline. Shortages of FFRs, including N95 masks, have led public health agencies to provide guidance in favor of FFR decontamination and re-use as a crisis capacity strategy.

SARS-CoV-2 is a respiratory virus. Transmission occurs by droplets, contact and aerosols. In medical settings, filtering facepiece (FFP) respirators are recommended for use by personnel exposed to aerosol-generating procedures. During the COVID-19 pandemic, the demand for FFP respirators exceeded their supply worldwide and low-quality products appeared on the market, potentially putting healthcare workers at risk. To raise awareness about variations in quality of imported FFP respirators in Switzerland during the COVID-19 pandemic, to draw attention to the current directives regulating the market launch of FFP respirators in Switzerland, to provide practical support in identifying suspicious products or documents and, finally, to offer strategies aimed at reducing the distribution of low-quality FFP respirators in the future. Three Swiss laboratories, Spiez Laboratory and Unisanté in partnership with TOXpro SA individually set up testing procedures to evaluate aerosol penetration and fit testing of FFP respirators imported into Switzerland during COVID-19 pandemic. Additionally, Spiez Laboratory visually inspected the products, examined the certification documents and crosschecked the product information with international databases. Between 31 March and 15 June 2020, 151 FFP respirators were analysed. The initial assessment performed before testing allowed a reduction of up to 35% in the number of FFP respirators sent to Spiez Laboratory for evaluation, for which product information found to be faulty. After filtration efficiency evaluation and fit testing, 52% and 60% of all products tested by Spiez Laboratory and Unisanté-TOXpro SA, respectively, did not meet the minimum performance requirements established independently by the three Swiss laboratories. The demand for FFP respirators exceeded the supply capacity from established suppliers of the Swiss market. New production and import channels emerged, as did the number of poor-quality FFP respirators. FFP respirators remaining in stocks should be checked for conformity before being used, or eliminated and replaced if quality does not meet standards.

During the COVID-19 pandemic, N95 filtering facepiece respirators (FFRs) were recommended to protect healthcare workers when providing care to infected patients. Despite their single-use disposable nature, the need to disinfect and repurpose FFRs is paramount during this global emergency. The objectives of this study were to (1) determine if UV treatment has an observable impact on respirator integrity; (2) test the impact of UV treatment on N95 FFR user fit; and (3) test the impact of UV treatment on FFR integrity. Ultraviolet (UV) disinfection was assessed in maintaining N95 FFR integrity. Two models of FFRs were exposed to UV fluences ranging from 0 to 10,000 mJ cm−2 per side and subsequently tested for fit, respirator integrity, and airflow. Inspection of N95 FFRs before and after UV treatment via microscopy methods showed no observable or tactile abnormalities in the integrity of respirator material or straps. Tensile loading tests on UV-treated and untreated respirator straps also demonstrated no impact on breaking strength. Standardized fit test methods showed no compromise in user fit following UV treatment. Evaluation of particle penetration and airflow through N95 FFRs showed no impact on integrity, and average filtration efficiency did not fall below 95% for any of the respirator types or fluence levels. This work provides evidence that UV disinfection does not compromise N95 FFR integrity at UV fluences up to 10,000 mJ cm−2. UV disinfection is a viable treatment option to support healthcare professionals in their strategy against the spread of COVID-19.

New technique to evaluate decontamination methods for filtering facepiece respirators

Evaluation of Five Decontamination Methods for Filtering Facepiece Respirators

Frontline healthcare workers have a high risk of exposure to SARS-CoV-2 coronavirus, which causes COVID-19. The use of appropriate personal protective equipment (PPE) is essential to prevent this occupational disease. Surgical masks and filtering face piece (FFP) respirators are important parts of this PPE. European standard EN 149 establishes three protection levels for FFP respirators (FFP1, FFP2, FFP3), depending on the particle infiltration degree through their materials, and these, in turn, are based on their filtration effectiveness. The aim of this laboratory test is to determine and quantify the filtration and fit rate of different FFP respirators, singly and in combination with surgical masks, by performing a series of fit tests and consequently, to check whether this combination improves protection levels for healthcare workers who care for COVID-19 patients. Several FFP respirators and surgical masks, singly and in combination, were fit tested with a PortaCount Pro + 8038, which fulfills OSHA standards, in a series of tests performed on healthcare workers in seven different breathing situations when taking care on COVID-19 patients, in order to determine and quantify their fit to the workers' face. Wearing a surgical mask together with a highly efficient FFP respirator provided increased respiratory protection. Interestingly, one of these highly efficient FFP models, combined with a surgical mask, achieved a protection factor over 200 (whereas 100 is the minimum required protection factor). Surgical masks, when used together with a FFP2 respirator, could significant ly improve the degree of fit of all self-filtering face piece by providing greater filtration efficiency and greater user protection from exposure to aerosols.

The objective of this study was to determine if ultraviolet germicidal irradiation (UVGI), moist heat incubation (MHI), or microwave-generated steam (MGS) decontamination affects the fitting characteristics, odor, comfort, or donning ease of six N95 filtering facepiece respirator (FFR) models. For each model, 10 experienced test subjects qualified for the study by passing a standard OSHA quantitative fit test. Once qualified, each subject performed a series of fit tests to assess respirator fit and completed surveys to evaluate odor, comfort, and donning ease with FFRs that were not decontaminated (controls) and with FFRs of the same model that had been decontaminated. Respirator fit was quantitatively measured using a multidonning protocol with the TSI PORTACOUNT Plus and the N95 Companion accessory (designed to count only particles resulting from face to face-seal leakage). Participants’ subjective appraisals of the respirator's odor, comfort, and donning ease were captured using a visual analog scale survey. Wilcoxon signed rank tests compared median values for fit, odor, comfort, and donning ease for each FFR and decontamination method against their respective controls for a given model. Two of the six FFRs demonstrated a statistically significant reduction (p < 0.05) in fit after MHI decontamination. However, for these two FFR models, post-decontamination mean fit factors were still ≥100. One of the other FFRs demonstrated a relatively small though statistically significant increase (p < 0.05) in median odor response after MHI decontamination. These data suggest that FFR users with characteristics similar to those in this study population would be unlikely to experience a clinically meaningful reduction in fit, increase in odor, increase in discomfort, or increased difficulty in donning with the six FFRs included in this study after UVGI, MHI, or MGS decontamination. Further research is needed before decontamination of N95 FFRs for purposes of reuse can be recommended.

Guidance on the use of respiratory and facial protection equipment

Effectiveness of Three Decontamination Treatments against Influenza Virus Applied to Filtering Facepiece Respirators

The coronavirus disease 2019 (COVID-19) pandemic has resulted in shortages of personal protective equipment (PPE), underscoring the urgent need for simple, efficient, and inexpensive methods to decontaminate masks and respirators exposed to severe acute respiratory coronavirus virus 2 (SARS-CoV-2). We hypothesized that methylene blue (MB) photochemical treatment, which has various clinical applications, could decontaminate PPE contaminated with coronavirus. The 2 arms of the study included (1) PPE inoculation with coronaviruses followed by MB with light (MBL) decontamination treatment and (2) PPE treatment with MBL for 5 cycles of decontamination to determine maintenance of PPE performance. MBL treatment was used to inactivate coronaviruses on 3 N95 filtering facepiece respirator (FFR) and 2 medical mask models. We inoculated FFR and medical mask materials with 3 coronaviruses, including SARS-CoV-2, and we treated them with 10 µM MB and exposed them to 50,000 lux of white light or 12,500 lux of red light for 30 minutes. In parallel, integrity was assessed after 5 cycles of decontamination using multiple US and international test methods, and the process was compared with the FDA-authorized vaporized hydrogen peroxide plus ozone (VHP+O3) decontamination method. Overall, MBL robustly and consistently inactivated all 3 coronaviruses with 99.8% to >99.9% virus inactivation across all FFRs and medical masks tested. FFR and medical mask integrity was maintained after 5 cycles of MBL treatment, whereas 1 FFR model failed after 5 cycles of VHP+O3. MBL treatment decontaminated respirators and masks by inactivating 3 tested coronaviruses without compromising integrity through 5 cycles of decontamination. MBL decontamination is effective, is low cost, and does not require specialized equipment, making it applicable in low- to high-resource settings.