Decontamination and Reuse of Filtering Facepiece Respirators

Vaporous hydrogen peroxide, ultraviolet germicidal irradiation, and moist warmth are probably the most promising decontamination strategies. If FFR decontamination is taken into account, these strategies don’t seem to interrupt down filtration or compromise the FFR; nevertheless, many of those strategies can solely be used for restricted occasions.

Vaporous hydrogen peroxide (VHP)

Investigations into VHP decontamination of FFRs present proof of minimal impact to filtration and match whereas demonstrating 99.9999% effectivity in killing bacterial spores. VHP didn’t cut back the filtration efficiency of ten N95 FFR fashions examined whereas exhibiting a 6-log discount in Geobacillus stearothermophilus spores [2-4].

In a report ready by Battelle Memorial Institute, the 3M 1860 FFR was proven to take care of filtration efficiency for 50 remedy cycles of VHP, additionally known as HPV by some decontamination system producers, utilizing the Clarus® R HPV generator type Bioquell (using 30% H2O2). Additionally, FFR match was proven to be unaffected for as much as 20 VHP therapies cycles utilizing NPPTL’s Static Advanced Headform [4, 5]. Strap degradation occurred after 20 remedy cycles. Kenney et al. co-contaminated 3M 1870 FFRs with three bacteriophages, T1, T7, and Phi 6, and decontaminated the FFRs utilizing VHP generated from the Bioquell’s BQ-50 system. The VHP remedy was proven to inactivate >99.999% of all phages which was under the restrict of detection [6].

Viscusi et al. discovered that 9 FFR fashions (three particulate N95, three surgical N95 FFRs and three P100) uncovered to at least one cycle of VHP remedy utilizing the STERRAD 100S H2O2 Gas Plasma Sterilizer (Advanced Sterilization Products, Irvine, CA) had filter aerosol penetration and filter airflow resistance ranges just like untreated fashions; nevertheless, Bergman et al. discovered that three cycles of VHP remedy utilizing the STERRAD 100S H2O2 Gas Plasma Sterilizer negatively affected filtration efficiency [2, 3].

Bergman et al. measured acceptable filtration efficiency for six FFR fashions (three particulate and three surgical FFRs) that acquired three cycles of VHP remedy utilizing the Clarus® R HPV generator (using 30% H2O2) [3]. VHP is a promising methodology with a possible for prime capability throughput, however sure VHP methods, such because the Clarus® R HPV generator, could also be extra appropriate for FFR decontamination.

Ultraviolet germicidal irradiation (UVGI)

UVGI is a promising methodology however the disinfection efficacy depends on dose. Not all UV lamps present the identical depth thus remedy occasions must be adjusted accordingly. Moreover, UVGI is unlikely to kill all of the viruses and micro organism on an FFR resulting from shadow results produced by the a number of layers of the FFR’s development.

Acceptable filtration efficiency was recorded for eleven FFR fashions uncovered to numerous UV doses starting from roughly 0.5–950 J/cm2 and UVGI was proven to have minimal impact on match [2, 3, 7, 8, 9, 10]. Heimbuch et al. examined filtration and match of 15 FFRs and located no antagonistic results to FFR efficiency [11]. Lindsley et al. reported a discount of the sturdiness of supplies of the FFRs for doses starting from 120–950 J/cm2; nevertheless, an approximate inactivation of 99.9% of bacteriophage MS2, a non-enveloped virus, and H1N1 influenza A/PR/8/34 had been achieved with a lot decrease doses of roughly 1 J/cm2 [12–14]. Heimbuch et al. examined the efficiency of 1 J/cm2 of UVGI towards Influenza A (H1N1), Avian influenza A virus (H5N1), Influenza A (H7N9) A/Anhui/1/2013, Influenza A (H7N9) A/Shanghai/1/2013, MERS-CoV, and SARS-CoV and reported virus inactivation from 99.9% to better than 99.999% [11].

UVGI is dangerous. Proper precautions are required to keep away from UVGI publicity to pores and skin or the eyes.

Moist warmth

Moist warmth, consisting of 60°C and 80% relative humidity (RH) brought on minimal degradation within the filtration and match efficiency of the examined FFRs [3, 9, 10]. Heimbuch et al. disinfected FFRs contaminated with H1N1 influenza utilizing moist warmth, of 65°C and 85% RH, and achieved a minimal of 99.99% discount in virus [14].

One limitation of the moist warmth methodology is the uncertainty of the disinfection efficacy for numerous pathogens.

Steam remedy

Steam remedy could also be an acceptable strategy for decontaminating FFRs. The restricted variety of research for steam report minimal impact on FFR filtration and match efficiency and a minimal of 99.9% discount in H1N1 influenza and bacteriophage MS2 [14, 15].

Fisher et al. used microwave steam luggage, designed for disinfecting toddler feeding gear, to decontaminate six FFR fashions and achieved 99.9% inactivation of MS2 bacteriophage. Filtration efficiency of all examined FFRs scored above NIOSH certification necessities. Three FFRs had been additional evaluated for 3 cycles of steam publicity and demonstrated no change in filtration efficiency [15]. Bergman et al. additionally demonstrated acceptable filtration efficiency after three cycles of publicity to microwave generated steam [3]. Microwave generated steam had little impact on FFR match after publicity to as much as three cycles of steam [9, 10].

Using microwaves to supply steam to decontaminate FFRs just isn’t with out limitations. Not all microwaves are constructed the identical and a few are extra highly effective than others. The impact of upper energy microwaves on FFRs is unknown. Furthermore, the metallic nosebands of FFRs might trigger arcing, sparks contained in the microwave oven, throughout publicity to microwaves.

Liquid hydrogen peroxide

Liquid hydrogen peroxide confirmed no impact on FFR filtration efficiency [3, 7]. Bergman et al. evaluated six FFRs for filtration efficiency after a 30-minute submersion in 6% hydrogen peroxide. All six FFR fashions examined demonstrated no adjustments in filter efficiency after three cycles of decontamination. FFR match and disinfection efficacy weren’t assessed for this methodology.

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