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N95 Respirators and Surgical Masks | Blogs


 

With the advent of a novel H1N1 influenza outbreak in spring 2009 and the expectation of a second wave during the 2009–2010 flu season, there has been considerable interest in the use of surgical masks (facemasks) and respirators as infection control measures. Although their appearance is often similar, respirators are designed and engineered for distinctly different functions than surgical masks. The amount of exposure reduction offered by respirators and surgical masks differs. The National Institute for Occupational Safety and Health (NIOSH) and the Centers for Disease Control and Prevention (CDC) recommend the use of a NIOSH-certified N95 or better respirator for the protection of healthcare workers who come in direct contact with patients with H1N1.

The CDC guidance can be found in Interim Guidance on Infection Control Measures for 2009 H1N1 Influenza in Healthcare Settings. In September 2009 the Institute of Medicine released a report “Respiratory Protection for Healthcare Workers in the Workplace Against Novel H1N1 Influenza A” that also recommends N95 respirators for the protection of healthcare workers from H1N1. This blog examines the scientific principles behind the design and performance of surgical masks and respirators. Although these principles apply to all particulate respirators, the discussion presented in this article is focused on the most frequently used respirator in healthcare settings, the N95 filtering facepiece respirator (FFR).

Evolution of Respiratory Protection against Particulate Exposures

Early surgical masks were constructed from layers of cotton gauze. They were first worn by surgery staff in the early 1900s to prevent contamination of open surgical wounds. With time their design, function, and use have expanded. Today surgical masks are worn in a wide range of healthcare settings to protect patients from the wearers’ respiratory emissions. A surgical mask is a loose-fitting, disposable device that prevents the release of potential contaminants from the user into their immediate environment. In the U.S., surgical masks are cleared for marketing by the U.S. Food and Drug Administration (FDA). They may be labeled as surgical, laser, isolation, dental, or medical procedure masks. They may come with or without a face shield. Since OSHA issued the Bloodborne Pathogens Standard (29 CFR 1910.1030) in 1991, surgical masks have been recommended as part of universal precautions to protect the wearer from direct splashes and sprays of infectious blood or body fluids. (The FDA offers further information on surgical masks.)

The first modern respirators were also developed in the early 1900s. The impetus for their development derived from the need to protect miners from hazardous dusts and gases, soldiers from chemical warfare agents, and firefighters from smoke and carbon monoxide. In 1919, the U.S. Bureau of Mines published the first respirator performance standards for self-contained breathing apparatus for use in mines and for gas masks for use by soldiers against chemical warfare agents. Today respirators are found in a broad range of workplaces. Their use in healthcare settings dates to the 1990s in response to concerns about employee exposures to drug-resistant tuberculosis. Healthcare worker illnesses and deaths during outbreaks of severe acute respiratory syndrome (SARS) in the early 2000s led to renewed attention to the use of respirators for some infectious respiratory diseases. Most recently, planning efforts for pandemic influenza in 2006-07 led to considerable discussion about the role of small particle inhalation in disease transmission and the use of respirators to protect healthcare personnel from airborne influenza particles. A listing of all NIOSH-approved disposable, or filtering facepiece, respirators is available. NIOSH also maintains a database of all NIOSH-approved respirators regardless of respirator type—the Certified Equipment List.

Whether the goal is to prevent the outward escape of user-generated aerosols or the inward transport of hazardous airborne particles, there are two important aspects of performance. First, the filter must be able to capture the full range of hazardous particles, typically within a wide range of sizes (<1 to >100 µm) over a range of airflow (approximately 10 to 100 L/min). Second, leakage must be prevented at the boundary of the facepiece and the face. However, it is not possible to assure the latter—good face seal performance—without first ensuring a well-functioning filter.

Filter Performance

The filters used in modern surgical masks and respirators are considered “fibrous” in nature—constructed from flat, nonwoven mats of fine fibers. Fiber diameter, porosity (the ratio of open space to fibers) and filter thickness all play a role in how well a filter collects particles. In all fibrous filters, three “mechanical” collection mechanisms operate to capture particles: inertial impaction, interception, and diffusion. Inertial impaction and interception are the mechanisms responsible for collecting larger particles, while diffusion is the mechanism responsible for collecting smaller particles. In some fibrous filters constructed from charged fibers, an additional mechanism of electrostatic attraction also operates. This mechanism aids in the collection of both larger and smaller particle sizes. This latter mechanism is very important to filtering facepiece respirator filters that meet the stringent NIOSH filter efficiency and breathing resistance requirements because it enhances particle collection without increasing breathing resistance.

How do filters collect particles?

These capture, or filtration, mechanisms are described as follows:

Diagram illustrating the filtration mechanisms of inertial impaction, interception, diffusion, and electrostatic attraction. In each case, fibers are shown filtering particles.
Figure 1: Filtration mechanisms
  • Inertial impaction: With this mechanism, particles having too much inertia due to size or mass cannot follow the airstream as it is diverted around a filter fiber. This mechanism is responsible for collecting larger particles.
  • Interception: As particles pass close to a filter fiber, they may be intercepted by the fiber. Again, this mechanism is responsible for collecting larger particles.
  • Diffusion: Small particles are constantly bombarded by air molecules, which causes them to deviate from the airstream and come into contact with a filter fiber. This mechanism is responsible for collecting smaller particles.
  • Electrostatic attraction: Oppositely charged particles are attracted to a charged fiber. This collection mechanism does not favor a certain particle size.

In all cases, once a particle comes in contact with a filter fiber, it is removed from the airstream and strongly held by molecular attractive forces. It is very difficult for such particles to be removed once they are collected. As seen in Figure 2, there is a particle size at which none of the “mechanical” collection mechanisms (interception, impaction, or diffusion) is particularly effective. This “most penetrating particle size” (MPPS) marks the best point at which to measure filter performance. If the filter demonstrates a high level of performance at the MPPS, then particles both smaller AND larger will be collected with even higher performance.

This is perhaps the most misunderstood aspect of filter performance and bears repeating. Filters do NOT act as sieves. One of the best tests of a filter’s performance involves measuring particle collection at its most penetrating particle size, which ensures better performance for larger and smaller particles. Further, the filter’s collection efficiency is a function of the size of the particles, and is not dependent on whether they are bioaerosols or inert particles.

Graph showing a filter's efficiency on the Y-axis and particle diameter in microns along the X-axis. Efficiency falls in the 'Diffusion and Interception Regime'.
Figure 2: Filter efficiency versus particle diameter

How are surgical masks and respirator filters tested?

Respirator filters must meet stringent certification tests (42 CFR Part 84) established by NIOSH. The NIOSH tests use what are considered “worst case” parameters, including:

  • A sodium chloride (for N-series filters) or a dioctyl phthalate oil (for R- and P-series filters) test aerosol with a mass median aerodynamic diameter particle of about 0.3 µm, which is in the MPPS-range for most filters
  • Airflow rate of 85 L/min, which represents a moderately-high work rate
  • Conditioning at 85% relative humidity and 38°C for 24 hours prior to testing
  • An initial breathing resistance (resistance to airflow) not exceeding 35 mm water column* height pressure and initial exhalation resistance not exceeding 25 mm water column height pressure
  • A charge-neutralized aerosol
  • Aerosol loading conducted to a minimum of 200 mg, which represents a very high workplace exposure
  • The filter efficiency cannot fall below the certification class level at any time during the NIOSH certification tests

* Millimeters (mm) of water column is a unit for pressure measurement of small pressure differences. It is defined as the pressure exerted by a column of water of 1 millimeter in height at defined conditions, for example 39°F (4°C) at standard gravity.

As a result of these stringent performance parameters, fiber diameters, porosity, and filter thicknesses of all particulate filters used in NIOSH-certified respirators, including N95s, are designed and engineered to provide very high levels of particle collection efficiencies at their MPPS.

Manufacturers of surgical masks, on the other hand, must demonstrate that their product is at least as good as a mask already on the market to obtain “clearance” for marketing. Manufacturers may choose from filter tests using a biological organism aerosol at an airflow of 28 L/min (bacterial filtration efficiency) or an aerosol of 0.1 µm latex spheres and a velocity ranging from 0.5 to 25 cm/sec (particulate filtration efficiency). It is important to note that the Food and Drug Administration specifies that the latex sphere aerosol must not be charge-neutralized.

The generation of the test aerosol can impart a charge on a higher percentage of the aerosolized particles than may normally be expected in workplace exposures. A charge-neutralized test aerosol, like those used in the NIOSH tests, has the charges on the aerosolized particles reduced to an equilibrium condition. Therefore, higher filter efficiency values than would be expected with the use of charge-neutralized aerosols may result due to the collection of charged particles by the filters’ electrostatic attraction properties. Additionally, allowing the manufacturer to select from a range of air velocity means that the test results can be easily manipulated. In general, particles are collected with higher efficiency at lower velocity through a filter.

Both of these aspects yield a test that is not necessarily “worst case” for a surgical mask filter. Because the performance parameters for surgical masks are less stringent than those required for filters used in NIOSH-certified respirators, the fiber diameters, porosity, and filter thicknesses found in surgical masks are designed with significantly lower levels of particle collection efficiencies at their MPPS.

How do surgical mask and respirator filters perform?

Respirator filters that collect at least 95% of the challenge aerosol are given a 95 rating. Those that collect at least 99% receive a “99” rating. And those that collect at least 99.97% (essentially 100%) receive a “100” rating. Respirator filters are rated as N, R, or P for their level of protection against oil aerosols. This rating is important in industry because some industrial oils can remove electrostatic charges from the filter media, thereby degrading (reducing) the filter efficiency performance. Respirators are rated “N” if they are not resistant to oil, “R” if somewhat resistant to oil, and “P” if strongly resistant (oil proof). Thus, there are nine types of particulate respirator filters:

  • N95, N-99, and N-100
  • R-95, R-99, and R-100
  • P-95, P-99, and P-100

Respirator filters are tested by NIOSH at the time of application and periodically afterward to ensure that they continue to meet the certification test criteria. The FDA does not perform an independent evaluation of surgical mask filter performance, nor does it publish manufacturers’ test results. In many cases it is difficult to find information about the filter test results for FDA-cleared surgical masks. The class of FDA-cleared surgical masks known as Surgical N95 Respirators is the one clear exception to this uncertainty of filter performance. This is the only type of surgical mask that includes evaluation to the stringent NIOSH standards. All members of this class of surgical masks have been approved by NIOSH as N95 respirators prior to their clearance by the FDA as surgical masks. The FDA, in part, accepts the NIOSH filter efficiency and breathing resistance test results as exceeding the usual surgical mask requirements.

In studies comparing the performance of surgical mask filters using a standardized airflow, filter performance has been shown to be highly variable. Collection efficiency of surgical mask filters can range from less than 10% to nearly 90% for different manufacturers’ masks when measured using the test parameters for NIOSH certification. Published results on the FDA-required tests (if available) are not predictive of their performance in these studies.

It is important to keep in mind that overall performance of any facepiece for particulate filtering depends, first, on good filter performance. A facepiece or mask that fits well to the face but has a poor filter will not be able to provide a high level of protection.

Respirator and Surgical Mask Fit

Because respirator filters must meet stringent certification requirements, they will always demonstrate a very high level of collection efficiency for the broad range of aerosols encountered in workplaces. There has been some recent concern that respirator filters will not collect nano-sized particles, but research has demonstrated that such particles are collected with efficiencies that meet NIOSH standards. This is not surprising, because NIOSH tests employ small, charge-neutralized, relatively monodisperse aerosol particles and a high airflow.

Thus, the most important aspect of a NIOSH-certified respirator’s performance will be how well it fits to the face and minimizes the degree of leakage around the facepiece. This must be measured for each individual and their selected respirator. Selecting the right respirator for a particular workplace exposure depends largely on selecting the right level of protection.

Respirator fit depends on two important design characteristics:

  • Whether the respirator operates in a “negative pressure” or “positive pressure” mode
  • The type of facepiece and degree of coverage on the face

Respirators that operate in a “negative pressure” mode require the wearer to draw air through an air-cleaning device (filter or chemical cartridge) into the facepiece, which creates a pressure inside the respirator that is negative in comparison to that outside the facepiece. A “positive pressure” respirator, on the other hand, pushes clean air into the facepiece through the use of a fan or compressor, creating a positive pressure inside the facepiece when compared to the outside. Negative pressure respirators inherently offer less protection than positive pressure respirators, because inward leakage occurs more easily in the former.

The facepiece design is also very important—some designs fit on the face better than others. It is more difficult to fit a half-facepiece respirator (one that covers the mouth and nose only) than a full-facepiece respirator (one that also covers the eyes). The nose and chin are the most difficult facial features on which to establish a tight fit. The fit of a hood, helmet or “loose-fitting” facepiece is highly dependent on the specific design and configuration. More details on the different classes of respirators and their levels of protection, can be found on the NIOSH respirator topic page and the OSHA Respiratory Protection Standard

Because fit is so important, NIOSH recommends and OSHA requires that each respirator wearer receive an initial fit test and annual fit tests thereafter. It is not possible to predict how well a respirator will fit on a particular face, even for respirators that fit well on a broad range of facial sizes. The FDA does not recommend or require any test of fit for surgical masks. A very limited number of published studies are available on this aspect of surgical mask performance. Three clinical studies conducted in the 1980s and 90s found no difference in surgical infection rates when staff did not wear surgical masks.1, 2, 3

A recent laboratory study of five surgical masks with “good” filters found that 80–100% of subjects failed an OSHA-accepted qualitative fit test using Bitrex (a bitter tasting aerosol) and quantitative fit factors ranged from 4–8 (12–25% leakage) using a TSI Portacount.4 In contrast, the least protective type of respirator (negative pressure half mask) must have a fit factor (outside particle concentration divided by inside concentration) of at least 100 (1% leakage).

NIOSH would like to hear from you regarding your experiences working with NIOSH-approved respirators and FDA-cleared surgical masks. For example, are there user needs for increased comfort and wearability that NIOSH could help address? Do users feel that exhalation valves on disposable, filtering facepiece impact the wearer’s ability to successfully perform a user seal check? Are there certain aspects of filtering facepiece respirator design that could be improved for better fit? How would you compare the comfort and wearability of surgical masks and filtering facepiece respirators?

Additionally, the NIOSH Respirator Trusted-Source Information Page can help users identify NIOSH-approved respirators and learn how to use and obtain these products.

Dr. Brosseau is a faculty member in the University of Minnesota’s School of Public Health whose research focuses on the performance of respiratory protection, measurement of aerosols, and assessment of workplace exposures to hazardous materials and wastes. Dr. Brosseau was Chair of the ACGIH Threshold Limit Values for Chemical Substances Committee from 1995–2005 and is currently Vice Chair Elect of ACGIH.

Mr. Berry Ann is the Deputy Director of the NIOSH National Personal Protective Technology Laboratory. He has more than 15 years experience working in respirator certification and PPT issues at NIOSH.

References
  1. Orr, N. W. 1981. Is a mask necessary in the operating theatre? Annals of the Royal College of Surgeons of England 63, (6) (Nov): 390-2.
  2. Mitchell, N. J., and S. Hunt. 1991. Surgical face masks in modern operating rooms—a costly and unnecessary ritual? The Journal of Hospital Infection 18, (3) (Jul): 239-42.
  3. Tunevall, T. G. 1991. Postoperative wound infections and surgical face masks: A controlled study. World Journal of Surgery 15, (3) (May-Jun): 383,7; discussion 387-8.
  4. Oberg, T., and L. M. Brosseau. 2008. Surgical mask filter and fit performance. American Journal of Infection Control 36, (4) (May): 276-82.

 

The Centers for Disease Control and Prevention is addressing questions related to the Coronavirus Disease 2019 through CDC-INFO and on their webpage. As such, this blog has been closed to comments.  Please visit https://www.cdc.gov/coronavirus/2019-ncov/index.html. You can find the most up-to-date information on the outbreak and get the latest answers to frequently asked questions. If you have specific inquiries, please contact CDC-INFO at https://wwwn.cdc.gov/dcs/contactus/form or by calling 800-232-4636. If you have questions about PPE that are not related to Coronavirus Disease 2019, please contact us at PPEConcerns@cdc.gov.

 



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Filtration Performance of FDA-Cleared Surgical Masks


J Int Soc Respir Prot. Author manuscript; available in PMC 2020 Jul 13.

Published in final edited form as:

J Int Soc Respir Prot. 2009 Spring-Summer; 26(3): 54–70.

PMCID: PMC7357397

NIHMSID: NIHMS1604065

Abstract

Ashortage of NIOSH-approved respirators is predicted during an influenza pandemic and other infectious disease outbreaks. Healthcare workers may use surgical masks instead of respirators due to non-availability and for economical reasons. This study investigated the filtration performance of surgical masks for a wide size range of submicron particles including the sizes of many viruses. Five models of FDA-cleared surgical masks were tested for room air particle penetrations at constant and cyclic flow conditions. Penetrations of polydisperse NaCl aerosols (75±20 nm, count median diameter), monodisperse NaCl aerosols (20–400 nm range) and particles in the 20–1000 nm range were measured at 30 and 85 liters/min. Filtration performance of surgical masks varied widely for room air particles at constant flow and correlated with the penetration levels measured under cyclic flow conditions. Room air particle penetration levels were comparable to polydisperse and monodisperse aerosol penetrations at 30 and 85 liters/minute. Filtration performance of FDA-cleared surgical masks varied widely for room air particles, and monodisperse and polydisperse aerosols. The results suggest that not all FDA-cleared surgical masks will provide similar levels of protection to wearers against infectious aerosols in the size range of many viruses.

Keywords: Surgical mask, Filtration performance, Particle penetration, Virus particles, Nanoparticles

INTRODUCTION

The term “surgical mask” is used to refer to Food and Drug Administration (FDA)-cleared surgical, laser, isolation, dental, medical procedure or face masks with or without a face shield. Healthcare personnel often wear various types of surgical masks to provide protection against body fluid splashes to the nose and mouth. They are also worn by surgeons and other operating room personnel to prevent organisms in their noses and mouths from falling into the sterile field and potentially causing surgical site infections. Infection control guidance recommends placing surgical masks on potentially infectious patients to limit the dissemination of infectious respiratory secretions from patients to others. Surgical masks are often confused with filtering facepiece respirators (FFRs), because surgical masks look similar to respirators and both are worn on the face. The differences between surgical masks and respirators were discussed in a 2008 Institute of Medicine report on personal protective equipment for healthcare workers during an influenza pandemic (Goldfrank et al. 2008).

The FDA does not test and certify surgical masks, but clears them for sale after reviewing the manufacturer’s test data and proposed claims (FDA 2004). Manufacturers test surgical masks for particle filtration efficiency (PFE), bacterial filtration efficiency (BFE), fluid resistance, differential pressure and flammability, and submit the results for FDA clearance. For BFE measurements, surgical masks are tested with non-neutralized Staphylococcus aureus of 3 ± 0.3 μm diameter at a flow rate of 28.3 liters/minute (ASTM 2001; FDA 2004). Some types of surgical masks are also tested with 100 nm diameter non-neutralized polystyrene latex spheres (PSL) at 1 to 25 cm/second face velocity for PFE (ASTM 1989; FDA 2004). FDA-cleared surgical masks can be categorized into three types of medical face mask materials as specified in ASTM F 2100–04 (ASTM 2004). The high and moderate barrier masks are cleared with >98% filtration efficiency levels for both BFE and PFE tests, while the low barrier masks require >95% for the BFE test only (ASTM 2004). On the other hand, NIOSH certified respirators are tested under “near worst case” test conditions using charge-neutralized polydisperse aerosol particles at a high flow rate (85 liters/minute) (Federal Register 1995; NIOSH 2005). N class respirators are tested using NaCl aerosol with a count median diameter (CMD) of 75±20 nm, and P and R class respirators with dioctyl phthalate aerosol with a CMD of 185±20 nm. Class N, R and P respirators are certified at <5, <1 and <0.03% penetration levels. Unlike surgical masks, respirators are designed to fit and seal tightly to the face. Beginning in 2004, a new surgical mask category called “surgical N95 respirator” was also cleared by FDA for sale. The surgical N95 respirator is a NIOSH-approved N95 FFR, which also meets FDA-required fluid resistance and differential pressure tests (FDA 2008).

In response to the need for improved Mycobacterium tuberculosis infection control methods in the 1990s, several studies compared the filtration efficiency of surgical masks to respirators (Brosseau et al. 1997; Chen and Willeke 1992; Lenhart et al. 2004; Weber et al. 1993; Willeke et al. 1996). In one study, penetration of particles in the 150–4000 nm range at different flow rates using a manikin fitted with a mask or respirator were measured (Chen and Willeke 1992). Surgical masks showed penetration levels of approximately 55–85% and 70–90% at flow rates of 30 and 100 liters/minute, respectively, for 300 nm particles. The most penetrating particle size (MPPS) was in the 200–500 nm range. Surgical masks were found to be less efficient compared to dust-mist (DM) and dust-mist-fume (DMF) respirators. DM and DMF respirators were classifications of particulate respirators approved under 30 CFR 11 which was superseded by the current 42 CFR 84 regulations. Subsequent studies with eight different surgical masks showed penetration levels of 15–100% and 6–100% for 200 nm and 1000 nm size particles, respectively (Weber et al. 1993). Another study compared the efficiency of surgical masks to DM and DMF respirators against 550 nm polystyrene latex particles at 45 liters/minute and Mycobacterium abscessus (1.0–2.5 μm length × 0.5 μm width) particles at 45 and 85 liters/minute flow rates (Brosseau et al. 1997). Their results also confirmed that the efficiency level of surgical masks was less than that of DM and DMF respirators.

More recently, the filtration efficiency of surgical masks and N95 FFRs against MS2 virus particles in the 10–80 nm range was reported (Balazy et al. 2006). Penetration levels of one of the two surgical mask models tested increased with increasing particle size from 10 to 50 nm, and then plateaued at 20% up to 80 nm diameter at 85 liters/minute flow rates. A similar penetration pattern was obtained at 30 liters/minute flow rate, with a maximum penetration level of 13%. Another surgical mask showed a steady increase in penetration levels up to approximately 80% with increase in particle size from 10 nm to 80 nm.

Another recent study investigated particle filtration and face fit performance of surgical masks (Oberg and Brosseau 2008). This study reported high penetration levels for 9 surgical masks (5 were FDA-cleared surgical masks) commonly used in hospital and dental settings. Filtration efficiencies of various surgical masks were measured using monodisperse polystyrene latex spheres (PSL) of 895, 2000, and 3100 nm diameters at 6 liters/minute. A wide range of particle penetration levels (0–84%) was obtained for the three different size PSL particles. Surgical masks were also tested with polydisperse NaCl aerosol with a count median diameter of 75 nm using a TSI 8130 similar to the NIOSH particulate respirator certification test protocol. A wide range of penetration levels (4–90%) was obtained similar to PSL particles. The authors also reported that fit factor measurements using a Bitrex qualitative fit test failed all test subjects when masks were donned without assistance. After receiving assistance, the test failed all but two male subjects. Subjects were also tested for quantitative fit using a PortaCount® Plus (TSI). Maximum fit factors of 6.9 for unassisted donning and 9 for assisted donning were reported.

A detailed study on the filtration performance of surgical masks for particles in the submicron size range is lacking and is needed to confirm the earlier studies discussed above. This knowledge gap needs to be addressed, because, there is increased concern of human exposure to harmful airborne virus particles during pandemic events. A shortage of FFRs is predicted during an influenza pandemic (Bailar et al. 2006; CDC 2006). Workers and the general public may be tempted to use surgical masks instead of NIOSH-approved filtering facepieces (FFRs) for protection against airborne influenza virus when there is a shortage of FFRs during an influenza pandemic. For these reasons, filtration performance of FDA-cleared surgical masks was investigated for room air particles in the 20–1000 nm range and compared with the NIOSH particulate respirator test method using polydisperse NaCl, as well as ten different size monodisperse NaCl particles in the 20–400 nm range. It was hypothesized that the FDA-cleared surgical masks studied here would exhibit a wide range of filtration efficiencies against submicron particles across the various test methods employed, confirming the earlier studies.

MATERIALS AND METHODS

Surgical Masks

FDA-cleared surgical masks from five manufacturers were selected randomly and only one model from each manufacturer was used in the study. The manufacturer and model of the evaluated surgical masks were 3M (1800), Busse (370), CrossTex (GCS), Precept (1510), and Primed (PG4–1073). Of these five surgical masks, one model (A) was classified as high, two models as moderate (B and C) and the other two models as low barrier types (D and E) (ASTM 2004). shows manufacturer provided penetration levels for the FDA-cleared surgical masks. These surgical masks are not certified by NIOSH for respiratory protection.

Table I.

Filtration efficiency of FDA-cleared surgical masks

Manufacturer FDA Clearance Barrier Type Filtration efficiency (%)
Non-neutralized
Bacterial aerosol 100 nm polystyrene latex spheres ~100 nm room air particles
(BFE)* (PFE)*
A Yes High >98 >98 92.0
B Yes Medium >98 >98 85.5
C Yes Medium >98 >98 83.4
D Yes Low >95 NR NR
E Yes Low >95 NR NR

Room Air Particle Penetration at Constant Flow Condition

shows the schematic of the room air particle penetration test system. Briefly, laboratory room air particles were passed into a Plexiglas test box (20 cm × 20 cm × 10 cm) mounted with a surgical mask placed between the upstream and downstream filter chucks as described previously (Rengasamy et al. 2007). Upstream and downstream aerosol particles were counted by an ultra-fine condensation particle counter (UCPC, TSI 3025A) by sampling through ports, off each filter chuck, alternately. Particle counting was continued for 100 seconds irrespective of the number of particles downstream of the surgical masks. Percentage particle penetration was calculated by multiplying the ratio of the number of particles downstream to the number of particles upstream by 100.

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Schematic diagram of constant flow room air particle penetration test system.

Four samples of each surgical mask model were tested for the penetration of room air particles (control) at a constant flow rate. The same surgical masks were again tested for charge-neutralized particles by passing room air through a 85Kr source (TSI 3012), and then into the Plexiglas test box. When changing from control to neutralized particles, a 5 minute time was allowed for equilibration. Penetration levels at three different flow rates (6, 30, and 85 liters/minute) were measured and a separate set of four masks was tested for each flow rate.

Room Air Particle Penetration as a Function of Particle Size

Percentage penetration for each surgical mask was also measured as a function of particle size from 20–1000 nm using a Scanning Mobility Particle Sizer (SMPS, TSI, Inc.) in the scan mode. Particle concentration upstream and downstream of the surgical mask was measured using the Plexiglas box set up at 85 liters/minute. Room air particle concentrations for the 20–1000 nm size range particles were measured for 135 seconds for upstream and downstream samples, alternately. Percentage particle penetration was calculated by multiplying the ratio of the particle concentration downstream to upstream of the mask by 100.

Particle Penetration Measurement at Cyclic Flow Condition

Particle penetration levels for each surgical mask were measured under cyclic flow conditions. The set up used in this study allowed room air to go in and out of a rubber bladder, similar to a human lung, through a mask sealed on to a manikin (). The volume of air going through the mask per minute can be compared to minute volumes of human breathing, but not the cyclic pattern. Unlike human breathing, the tidal volume remains the same at different flow rates. Briefly, a surgical mask was fitted with a sampling port similar to that used for fit factor measurement for respirators with a PortaCount® Plus (TSI, Inc.). The surgical mask was sealed to a manikin using a silicone adhesive to eliminate any leakage around the seal, and was connected to the breathing pump (). Particle concentrations inside and outside of the mask were analyzed by sampling through the sampling port and outside of the manikin head, respectively, using two condensation particle counters. A set of four masks was tested for particle concentration against control room air particles at 6 and 30 liter minute volumes under cyclic flow conditions. Percentage penetration was calculated by multiplying the ratio of concentration of particles inside to outside of the mask by 100.

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Schematic diagram of cyclic flow room air particle test system.

Polydisperse NaCl Aerosol Penetration Measurement

A different set of three surgical masks was tested for polydisperse NaCl aerosol (75±20 nm, count median diameter) penetrations with a TSI 8130 Automated Filter Tester (TSI 8130) used for NIOSH particulate respirator tests (Federal Register 1995; NIOSH 2005). Initial penetration levels of NaCl particles were measured for 1 min, instead of conducting the entire NIOSH 42 CFR 84 test protocol. Percentage penetration was measured using the Plexiglas box set up as described previously (Rengasamy et al. 2007). Penetrations were measured at 30 and 85 liters/minute flow rates using separate sets of surgical masks to avoid any loading effects.

Monodisperse Aerosol Test Method

Another set of four surgical masks from the same models were tested against monodisperse NaCl particles using a TSI 3160 Fractional Efficiency Tester (TSI 3160) as described previously (Rengasamy et al. 2007). Initial percentage penetration levels of ten different monodisperse aerosols (20, 30, 40, 50, 60, 80, 100, 200, 300 and 400 nm) were measured for each mask at 30 liters/minute and then at 85 liters/minute.

Effect of Isopropanol Treatment on Monodisperse Aerosol Penetrations

To better understand particle filtration by electrostatic mechanism, the surgical mask models tested for monodisperse particle penetrations were carefully removed from the Plexiglas box and dipped into isopropanol for 1 min, removed and allowed to dry in a fume hood overnight. Monodisperse aerosol penetrations were again measured for each of these surgical masks as described previously. Previous studies showed that liquid isopropanol treatment of electret filters reduced or removed electrical charges associated with fibrous filters and increased particle penetration in laboratory experiments (Chen and Huang 1998; Chen et al. 1993; Martin and Moyer 2000).

Data Analysis

The data were analyzed using the SigmaStat® (Jandel Corporation) computer program. Average and 95% confidence interval penetration levels were calculated for each model. Correlation coefficients between variable parameters were calculated using the Pearson Product Moment Correlation method.

RESULTS

Room Air Particle Penetration at Constant Flow Condition

Percentage penetration levels of control and charge-neutralized room air particles were measured for four samples from each of the surgical mask models at 6, 30 and 85 liters/minute constant flow rates. shows that the percentage penetrations of control room air particles were less than 10% for four models (A, B, C, and D) at 6 liters/minute and for two models (A, and B) at both 30 and 85 liters/minute. Model E showed >46% at 6 liters/minute, which increased to 76% at 85 liters/minute flow rate. In general, penetration levels of control room air particles did not differ from the penetrations obtained for charge-neutralized room air particles at 6, 30 and 85 liters/minute flow rates.

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Percentage penetration levels of control (empty bars) and charge neutralized (hatched bars) room air particles for surgical masks at 6, 30 and 85 liters/minute constant flow rates.

Room Air Particle Penetration as a Function of Particle Size

Room air particles were size classified using an SMPS and the penetration levels of particles in the 20–1000 nm was measured at 6, 30 and 85 liters/minute flow rates. In general, percentage penetration levels increased from 20 nm, reached a maximum and then decreased up to 1000 nm. shows that the penetration levels at 85 liters/minute flow rate peaked at 50 nm for one model (A) and at ~130 nm for two models (B and C) and ~200–400 nm for the other two models. Control and charge-neutralized room air particles showed more or less similar penetration levels for the different size particles in the 20–1000 nm range. The mean penetration values for non-neutralized room air particles in the range of 95–105 nm were integrated to represent the penetration levels for 100 nm size particles to allow comparisons with test methods specified in ASTM 2100–04. Percentage penetration levels were 8.0, 24.5, 27.6, 45.1 and 89.8 for surgical mask models A, B, C, D and E, respectively. In other words, the efficiency levels were 92% for the high barrier mask (A), 83.4–85.5% for the moderate barrier masks (B and C) and 11.2–54.9% for the low barrier masks (D and E) (). Similarly, the filtration efficiency levels integrated for 500–1000 nm particles were 97.7% for high barrier mask (A), 77.6–86.2% for moderate barrier masks (B and C) and 57.9–88.6% for low barrier masks (D and E).

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Size dependent penetration data from SMPS measurements of room aerosol at 85 liters/minute flow rate. A, B, C, D and E represent different surgical mask models.

Room Air Particle Penetrations at Constant and Cyclic Flow Conditions

Room air particle penetrations of surgical masks under constant flow using the Plexiglas box set up and cyclic flow using the manikin set up are compared in . Percentage penetration levels for different models varied between 0.7–51 and 2.2–67.7 at 6 and 30 liters/minute constant flow rates, respectively. These values were compared with the range of filter penetration levels 1.3–50.6% and 5.1–60.9% measured at 6 and 30 liters/minute cyclic flow conditions, respectively. In general, penetration levels measured at constant flow rates showed good correlations (r > 0.96 and r>0.97) with the penetration levels measured under cyclic flow rates.

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Correlation of surgical mask penetration levels at constant flow rates with penetration levels measured at cyclic flow conditions. Straight lines are linear best fit lines of the two data sets.

Polydisperse Aerosol Penetrations

shows penetration levels for polydisperse aerosols measured using the TSI 8130. One surgical mask model (A) showed less than 5% penetration at both 30 and 85 liters/minute flow rates. Penetration levels were in the 5–20% range for three models (B, C and D) at 30 liters/minute and two models (B and C) at 85 liters/minute. Model E had 63.3% penetration at 30 liters/minute, which increased to 88.0% at 85 liters/minute.

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Polydisperse aerosol penetration levels of five surgical mask models as measured by a TSI 8130 at 30 and 85 liters/minute.

Monodisperse Aerosol Penetrations

Another set of five surgical masks from each manufacturer were tested against ten different size monodisperse aerosol particles in the 20–400 nm range. Their initial penetrations levels were measured at 30 and 85 liters/minute flow rates. In general, penetration levels increased from 20 nm, reached a maximum at 40–400 nm (). Penetration levels for the different size monodisperse particles obtained at 85 liters/minute were higher than that at 30 liters/minute for all surgical masks. The MPPS was in the 40–60 nm range for three surgical mask models (A, B, and C) and 200–400 nm for two other models (D and E) at both 30 and 85 liters/minute flow rates.

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Monodisperse aerosol penetration levels of surgical masks as recorded by a TSI 3160. A, B, C, D and E represent surgical mask models.

Effect of Liquid Isopropanol Treatment on Monodisperse Aerosol Penetrations

shows that liquid isopropanol treatment increased the penetration levels of monodisperse particles in the 60–400 nm range for three surgical mask models (A, B, and C). The MPPS for these surgical mask models was shifted from 40–60 nm to the 200–400 nm range. The penetration levels of model D and E remained mostly at levels obtained for control surgical masks with no change in the MPPS.

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Monodisperse aerosol penetration data for isopropanol (IP) treated surgical masks measured with a TSI 3160. A, B, C, D and E represent surgical mask models.

Surface Area of Surgical Masks and Face Velocity

The surface area of the five surgical mask models tested in the study ranged from 135 –294 cm2 with an average of 230 cm2. This value was used for calculating the face velocities of 2.2 and 6.2 cm/second corresponding to 30 and 85 liters/minute flow rates.

DISCUSSION

Results from this study using five models of FDA-cleared surgical masks showed a wide variation in filtration performance from the four filtration test methods employed. Initial percentage penetrations for room air particles were in the range of 1.4 – 46.2, 6.7 – 65.7, and 7.5 – 76.3 at 6, 30 and 85 liters/minute constant flow rates, respectively. Similarly, polydisperse NaCl particle penetrations measured similar to the NIOSH certification test protocol were in the range of 0.2–63.3% and 1.6 – 88.1% at 30 and 85 liters/minute flow rates. Similar variation in filtration performance for surgical masks was reported in the literature (Chen and Willeke 1992; McCullough et al. 1997; Oberg and Brosseau 2008; Weber et al. 1993; Willeke et al. 1996). The wide variation in penetration levels can be partly explained by the particle penetration tests employed for testing the three different categories of surgical masks. For particulate filtration efficiency measurements, the low barrier surgical masks are tested for only BFE. The moderate and high level barrier surgical masks are not only tested for BFE, but also for PFE using 100 nm non-neutralized latex sphere particles at 1 to 25 cm/second face velocity (ASTM 1989; ASTM 2004). The high and moderate barrier masks are cleared for >98% filtration efficiency levels for PFE and BFE tests, while the low barrier type for >95% level for BFE tests (ASTM 2004). In our study, moderate and high barrier surgical masks showed filtration efficiency levels between 83.4–85.5% and 92% for 100 nm size NaCl particles at a face velocity of 6.2 cm/second (85 liters/minute). These filtration efficiency levels for moderate and high barrier surgical masks are less than those levels expected given that these surgical masks had been tested previously by manufacturers for performance using the test methods specified in ASTM F 2100–04 (ASTM 2004). The discrepancy in the penetration levels obtained for surgical masks in this study and the FDA specified penetration levels may be explained partly by the difference in the face velocity employed for testing surgical masks. For example, FDA requires surgical mask testing to be conducted according to ASTM F 2100–04 specifications. ASTM F 2100–04 describes a test method for surgical mask filter media at face velocities in the 1 to 25 cm/second range. This indicates that manufacturers can submit surgical mask penetration results obtained from tests conducted at any face velocity in the 1 to 25 cm/second range which can be a potential source for the wide variation in penetration values. Indeed, surgical mask model A was tested at a face velocity higher than that employed for the other models as informed by the manufacturers. A wide variation in penetration levels is expected because of the lack of FDA requirement for testing surgical masks at a specified face velocity.

Monodisperse aerosol particle penetrations were measured to determine the most penetrating particle size range for the surgical masks studied. The results for the different surgical masks showed markedly different penetration levels for ten different size monodisperse particles in the 20–400 nm range. The MPPS was in the 40–50 nm range with penetration levels <10% for one model and 20–30% for two other models at 85 liters/minute flow rate. The other two models showed that the MPPS was in the 200–400 nm range with penetration levels of 50–80%. The MPPS obtained with the TSI 3160 measurement was compared to the penetration values obtained for polydisperse aerosols with the TSI 8130. A good correlation (r=0.99) was obtained between the two penetration values (data not shown) similar to previous reports for N95 FFRs (Rengasamy et al. 2007) and non-certified dust masks (Rengasamy et al. 2008). The penetration levels at the MPPS obtained with the TSI 3160 measurement were compared to the MPPS values obtained with the room air particle penetration measurements using the SMPS in the scanning mode. The MPPS obtained for three surgical models (A, D and E) were similar by the two methods at 85 liters/minute flow rate. Models B and C showed that the MPPS was in the 40–60 nm range using the TSI 3160 and approximately 130 nm by the SMPS scanning data. The discrepancy can be explained partly by the filtration characteristics of surgical masks. For example, the slopes for penetration levels for monodisperse 40 to 100 nm is less for surgical mask models B and C compared to other models ().

Surgical mask models B and C showed an increase in polydisperse aerosol penetration levels by about 3-fold compared to 12-fold for model A after isopropanol treatment, suggesting that models B and C are weaker electrostatic filters with mild mechanical characteristics (data not shown). The mild mechanical nature of surgical masks B and C with a slope of close to zero for 40–100 nm monodisperse particle penetrations might have shifted the MPPS to 130 nm.

The dependence of surgical mask filtration efficiency on electrical charges of room air particles and filter media was investigated. Two approaches were attempted to gain insight into the role of electrical charges in capturing room air particles. The first one was aimed to understand whether room air particles carry net electrical charges and influence penetration levels. For this reason, penetrations were measured against room air particles with and without charge neutralization. The results from this set of experiments showed no significant difference in the penetration levels for control and charge-neutralized room air particles at three different flow rates (6, 30 and 85 liters/minute). This suggests that room air particles do not carry significant net charges to alter particle penetration levels. A previous study which investigated the electric charge for workplace aerosols in several factories, quarries and a coal mine showed approximately equal number of positive and negative charges (Johnston et al. 1985). This is consistent with the notion that comparatively aged ambient aerosol particles are neutralized to Boltzmann equilibrium (John 1980).

Secondly, the presence of electrical charges on surgical mask fibers used to enhance particle capturing was investigated. Liquid isopropanol is known to remove electrical charges from filter media fibers as revealed by a shift in the MPPS to a larger size and an increase in particle penetration level (Chen and Huang 1998; Chen et al. 1993; Martin and Moyer 2000). Results from this study showed that three of the five surgical masks showed a shift in the MPPS from 40–60 nm to 200–400 nm range suggesting the presence of electrical charges. The incorporation of electrical charges on filter fiber media is known to increase filtration efficiency without increasing the resistance (Barrett and Rousseau 1998). At the same time, the other two surgical masks showed neither a shift in the MPPS nor an increase in the penetration levels for different size monodisperse particles after isopropanol treatment suggesting the lack of electrical charges on the fiber media. The results suggest that the electrostatic surgical masks are more efficient in capturing submicron size particles compared to the mechanical type. Mechanical type filters can be made more efficient, but this increases the pressure drop making them harder to breathe through. Similar observations have been made for other types of filter media including those used for respiratory protection (Barrett and Rousseau 1998).

Interestingly, the penetration results obtained for FDA-cleared surgical masks in this study are similar to non-approved dust masks from local home improvement/hardware stores (Rengasamy et al. 2008). Surgical mask models tested in this study and dust mask models used in a previous study (Rengasamy et al. 2008) were randomly selected for investigation. The manufacturers of surgical masks were mostly different from the manufacturers of dust masks. Results showed that three models of surgical and dust masks were electrostatic and the rest were mechanical type. To our surprise, one electrostatic surgical model in this study and one dust mask model tested in the previous study (Rengasamy et al. 2008) obtained from different manufacturers, showed <5% penetration level when tested similar to NIOSH respirator certification test conditions at 85 liters/minute flow rate. The other two electrostatic surgical masks and two electrostatic dust mask models showed average penetration levels of 17.9–19.4% and 10–12%, respectively. On the other hand, the mechanical type surgical and dust masks showed penetration levels in the range of 51–89%.

The protection provided by a surgical mask is also dependent on face seal leakage of particles in addition to penetration through filter media. Leakage at the face/mask interface reduces the protection levels against particles. In this study, the penetration levels of surgical masks sealed to the manikin with a silicone sealant to prevent leakage varied widely. This suggests that a surgical mask user would be expected to get protection levels far less than that observed in this study, because a complete sealing of a surgical mask to a human face cannot be achieved during use. Indeed, none of the six surgical models tested in a previous study had good fitting characteristics (Lawrence et al. 2006). Another study showed that measurement of the protection factor using an Electrical Low Pressure Impactor (ELPI) did not exceed 10 for 9 different surgical mask models, which was 8–12 times lower than that obtained for N95 FFRs (Lee et al. 2008). Similarly, the quantitative fit factors measured using a PortaCount® Plus showed average fit factors ranging from 2.5 to 6.9 for unassisted donning and 2.8 to 9.6 for assisted donning (Oberg and Brosseau 2008).

A shortage of NIOSH-approved FFRs is predicted during an influenza pandemic (Bailar et al. 2006; CDC 2006). For respiratory protection, users may select surgical masks instead of respirators due to non-availability and for economical reasons. Use of surgical masks will not provide respiratory protection against airborne virus particles expelled by humans during talking, coughing, breathing or sneezing. For example, a recent study on the exhaled breath of influenza infected patients contained about 70% of influenza virus particles in the 300–500 nm range (Fabian et al. 2008). In addition, exhaled breath of normal subjects contained aerosol particles predominantly in the 150–199 nm range as measured by a six channel optical counter (Edwards et al. 2004). Similarly another study on normal subjects reported a majority of exhaled aerosol particles were <300 nm when measured using a laser spectrometer (Fairchild and Stampfer 1987). This suggests that droplet nuclei containing an influenza virion can potentially be <300 nm. Thus, a more aggressive standard filtration performance requirement (e.g. using neutralized submicron particles in the MPPS range) for surgical masks may be useful to discriminate between products that currently perform equivalently using the existing test methods cited by ASTM 2100–04.

FDA describes the purpose of using surgical masks as follows: “If worn properly, a facemask is meant to help block large-particle droplets, splashes, sprays or splatter that may contain germs (viruses and bacteria) from reaching your mouth and nose. Facemasks may also help reduce exposure of your saliva and respiratory secretions to others” (FDA 2008). The size of droplets and droplet nuclei generated by breathing, talking, and coughing (whatever the studies have looked at) vary among individuals (Fairchild and Stampfer 1987; Papineni and Rosenthal 1997; Yang et al. 2007). In addition, healthy human subjects and patients generate not only droplets, but also submicron size particles in the exhaled breath (Edwards et al. 2004; Fabian et al. 2008; Fairchild and Stampfer 1987; Papineni and Rosenthal 1997). In our study, moderate and high barrier level surgical masks showed filtration efficiency values of 77.6–97.7% for room air particles in the 500–1000 nm range. Wide variations (54.9–92%) in filtration efficiency levels were obtained for moderate and high barrier level surgical masks when challenged with 100 nm size room air particles at a face velocity of 6.2 cm/second. These categories of surgical masks were expected to have both BFE and PFE filtration efficiencies of >98 as is prescribed under the ASTM test protocols. The results from this study are consistent with the wide range of penetration values reported for different size particles in other studies (Brosseau et al. 1997; Chen and Willeke 1992; Oberg and Brosseau 2008). This suggests that not all FDA-cleared surgical masks will provide similar protection levels to the wearer of the mask to submicron particles even within the same barrier level category. The lack of an aggressive standard submicron particle penetration test method and performance requirement allows wide variations in penetration levels for FDA-cleared surgical masks. Setting standard penetration levels using aggressive test conditions for bacterial and virus size particles can improve the level of protection of surgical masks.

There are some limitations to the results obtained in the study. For example, only one high barrier, and two each of moderate and low barrier surgical masks were used to measure particle penetration levels. Other surgical mask models in the market may perform better or worse. Several surgical mask models should be tested to strengthen the conclusions. Similarly, the test data obtained in this study with the non-neutralized 100 nm size room air particles is not the same as those obtained with the monodisperse polystyrene latex particles cited in ASTM F2100–04 (ASTM 2004). Penetration of room air particles was measured as a function of a range of different size particles (20–1000 nm) in a shorter time (130 seconds), which is as accurate as the penetration levels measured with monodisperse aerosols. Thus, the results obtained in this study cannot be directly compared with the penetration values for FDA-cleared surgical masks.

CONCLUSIONS

Five FDA-cleared surgical mask models tested in the study showed wide variation in particle penetrations by the different test methods. Room air particle penetration for the different surgical models varied between 1.4–46.2%, 7.6–65.7% and 7.5–76.3% at 6, 30 and 85 liters/minute constant flow rates. Filtration efficiency of moderate and high barrier level surgical masks when challenged with room air particles in the 100 nm as well in the 500–1000 nm sizes were less than the expected >98% filtration efficiency. Room air particle penetrations under constant flow conditions correlated with penetration levels obtained at similar flow rates under cyclic flow conditions. Similar wide variations in penetrations for polydisperse as well as for different size monodisperse aerosols were obtained for the different surgical mask models. The MPPS size was in the 40–60 nm range for the three surgical mask models which shifted to 200–400 nm, after isopropanol treatment, suggesting that the masks contained electrically charged filter media. The electrostatic surgical masks showed better filtration performance compared to the mechanical types. The wide variation in penetration levels for room air particles, which included particles in the same size range of viruses confirms that surgical masks should not be used for respiratory protection. The wide variation in filtration performance for submicron size particles can be reduced by setting standard penetration levels for surgical masks using a more aggressive test procedure for submicron aerosols (e.g. charge-neutralized particles at the MPPS, higher flow rates, etc.).

Acknowledgements

The authors acknowledge NIOSH colleagues including Roland BerryAnn, Raymond Roberge and Lisa Delaney for their critical review of the manuscript and suggestions. This research work was supported by NIOSH funding-CAN #927 Z1NT.

Footnotes

Publisher’s Disclaimer: Disclaimer

Mention of commercial product or trade name does not constitute endorsement by the National Institute for Occupational Safety and Health. The findings and conclusions of this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

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USA-Made Surgical Masks – Armbrust American




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How Surgical Masks are Made, Tested and Used


Surgical masks, once simply a strip of cloth tied around the face of a doctor or nurse, are today manufactured using non-woven fabrics made from plastics like polypropylene to filter and protect. They are also available in many different styles and grades depending on the level of protection the user requires. Looking for more information on surgical masks to meet your medical sourcing needs? We’ve created this guide outlining some basics about these masks as well as how they’re manufactured. If you’re interested in finding out more information about how respirators, gowns, and other personal protection equipment is made, you can also visit our overview of how PPE is manufactured

Here’s what we’ll be going over:

  1. What are Surgical Masks Used for?
  2. Types of Masks
  3. C.D.C. Updated Guidelines for Mask Usage
  4. How are Surgical Masks Made?
  5. Surgical Mask Tests
  6. Can Any Manufacturer Become a Surgical Mask Manufacturer?
  7. Sourcing for Mask Materials 

What are Surgical Masks Used for?

Surgical masks are designed to keep operating rooms sterile, preventing germs from the mouth and nose of a wearer from contaminating a patient during surgery. Although they have seen a rise in popularity among consumers during outbreaks such as the coronavirus, surgical masks are not designed to filter out viruses, which are smaller than germs. For more on which types of masks are safer for medical professionals dealing with illnesses such as the coronavirus, you can read our article on the top CDC-approved suppliers.

It should be noted that recent reports from Healthline and the CDC show that masks featuring valves or vents are more likely to spread infection. The masks will provide the same protection for the wearer as an unvented mask, but the valve does not block viruses from coming out, which can enable someone unaware they are infected to spread the virus to others. It’s also important to note that a face shield without a mask is equally able to spread the virus

Types of Masks

There are four levels of ASTM certification that surgical masks are classified in, depending on the level of protection they provide to the person wearing them:

  • Minimum protection face masks are meant for short procedures or exams that won’t involve fluid, spray, or aerosol.
  • Level 1 face masks often feature ear loops and are the general standard for both surgical and procedural applications, with a fluid resistance of 80 mmHg. They’re meant for low-risk situations where there will be no fluid, spray, or aerosol.
  • Level 2 masks, with 120 mmHg fluid resistance, provide a barrier against light or moderate aerosol, fluid, and spray.
  • Level 3 face masks are for heavy possible exposure to aerosol, fluid and spray, with 160 mmHG fluid resistance.

It should be noted that surgical masks are not the same as surgical respirators. Masks are made to act as barriers to splashes or aerosols (such as the moisture from a sneeze), and they fit loosely to the face. Respirators are made to filter out airborne particles such as viruses and bacteria, and create a seal around the mouth and nose. Respirators should be used in cases when patients have viral infections or particles, vapor, or gas are present.

Surgical masks are also not the same as procedural masks. Procedural masks are used in clean environments in hospitals including intensive care and maternity units, but they are not approved for sterile environments such as the operating room.

CDC Updated Guidelines on Mask Usage

As of November 2020, the CDC has revised its guidelines on the use of masks to allow hospitals and other healthcare centers to stretch resources during this time of extreme demand. Their plan follows a series of steps for increasingly urgent situations from standard to crisis operations. Some emergency measures include:

  • Canceling elective procedures where face masks would be required.
  • Removing freely available masks from public areas and only issuing them to people coming in without masks to monitor their consumption.
  • Extended use of face masks, including wearing the same mask while seeing multiple patients. It’s important to note the mask is to be disposed of if it becomes soiled, damaged, or difficult to breathe through. Additionally, the wearer cannot touch the outside of the mask. Wearers should only remove the mask once they’re away from the patient care area.
  • Using masks past the manufacturer sell-by date, as long as they aren’t damaged.
  • Limited reuse of face masks, where they are taken off and put back on between seeing patients. This should only be done for masks that aren’t soiled, damaged, or difficult to breathe through. Masks should be stored while folded inward to avoid contamination, and tie back masks should not be used for this. Wearers should remove them only once they’re away from the patient care area.
  • For extreme situations, when there are no masks left, the CDC recommends healthcare workers vulnerable to the virus be excluded from working with potentially infected patients, and others wear face shields and cloth masks.

How are Surgical Masks Made?

Surgical face masks are made with non-woven fabric, which has better bacteria filtration and air permeability while remaining less slippery than woven cloth. The material most commonly used to make them is polypropylene, either 20 or 25 grams per square meter (gsm) in density. Masks can also be made of polystyrene, polycarbonate, polyethylene, or polyester.

20 gsm mask material is made in a spunbond process, which involves extruding the melted plastic onto a conveyor. The material is extruded in a web, in which strands bond with each other as they cool. 25 gsm fabric is made through meltblown technology, which is a similar process where plastic is extruded through a die with hundreds of small nozzles and blown by hot air to become tiny fibers, again cooling and binding on a conveyor. These fibers are less than a micron in diameter. 

Surgical masks are made up of a multi-layered structure, generally by covering a layer of textile with non-woven bonded fabric on both sides. Non-wovens, which are cheaper to make and cleaner thanks to their disposable nature, are made with three or four layers. These disposable masks are often made with two filter layers effective at filtering out particles such as bacteria above 1 micron. The filtration level of a mask, however, depends on the fiber, the way it’s manufactured, the web’s structure, and the fiber’s cross-sectional shape. Masks are made on a machine line that assembles the nonwovens from bobbins, ultrasonically welds the layers together, and stamps the masks with nose strips, ear loops, and other pieces.

Completed masks are then sterilized before being sent out of the factory.

Surgical Mask Tests

Once surgical masks are made, they must be tested to ensure their safety in various situations. There are five tests they must be put through:

  1. Bacteria filtration efficiency in vitro (BFE). This test works by shooting an aerosol with staphylococcus aureus bacteria at the mask at 28.3 liters per minute. This ensures the mask can catch the percentage of bacteria it’s supposed to.
  2. Particle Filtration Efficiency. Also known as the latex particle challenge, this test involves spraying an aerosol of polystyrene microspheres to ensure the mask can filter the size of the particle it’s supposed to.
  3. Breathing resistance. To ensure the mask will hold its shape and have proper ventilation while the wearer breathes, breathing resistance is tested by shooting a flow of air at it, then measuring the difference in air pressure on both sides of the mask.
  4. Splash resistance. In splash resistance tests, surgical masks are splashed with simulated blood using forces similar to human blood pressure to ensure the liquid cannot penetrate and contaminate the wearer.
  5. Flammability. Since several elements of an operating room can easily cause fire, surgical masks are tested for flammability by being set on fire to measure how slowly it catches and how long the material takes to burn. ASTM levels 1, 2, and 3 are all required to be Class 1 flame resistant.

Can Any Manufacturer Become a Surgical Mask Manufacturer?

It is possible for a generic manufacturer, such as a garment factory, to become a surgical mask manufacturer, but there are many challenges to overcome. It’s also not an overnight process, as products must be approved by multiple bodies and organizations. Hurdles include:

  • Navigating test and certification standards organizations. A company must know the web of test organizations and certification bodies as well as who can give them which services. Government agencies including the FDA, NIOSH, and OSHA set protection requirements for end users of products like masks, and then organizations such as the ISO and NFPA set performance requirements around these protection requirements. Then test method organizations such as ASTM, UL, or AATCC create standardized methods to ensure a product is safe. When a company wants to certify a product as safe, it submits its products to a certification body such as CE or UL, which then tests the product itself or uses an accredited third party testing facility. Engineers evaluate the test results against performance specifications, and if it passes, the organization puts its mark on the product to show it’s safe. All of these bodies are interrelated; employees of certification bodies and manufacturers sit on the boards of standards organizations as well as end users of the products. A new manufacturer must be able to navigate the interrelated web of organizations that handle its specific product to ensure the mask or respirator it creates is properly certified.
  • Navigating government processes. The FDA must approve surgical masks, which under pre-pandemic circumstances could be a long process, especially for a first-time company that hasn’t gone through the process before. However, the FDA has recently relaxed rules to allow some companies to get emergency use authorizations for surgical masks. It is also willing to work with manufacturers pivoting from other products. More information as of April 2020 can be found here.
  • Knowing the standards to which a product must be manufactured. Manufacturers need to know the testing that a product will go through so they can make it with consistent results and ensure it’s safe for the end user. The worst case scenario for a safety product manufacturer is a recall because it destroys their reputation. PPE customers can be difficult to attract since they tend to stick to proven products, especially when it could literally mean their lives are on the line.
  • Competition against large companies. Over the past decade or so, smaller companies in this industry have been acquired and consolidated into larger companies like Honeywell. Surgical masks and respirators are highly specialized products that larger companies with experience in this area can manufacture more easily. Partly from this ease, larger companies can also make them more cheaply, and therefore offer products at a lower price. Additionally, the polymers used in creating masks are often proprietary formulas.
  • Navigating foreign governments. For manufacturers specifically wishing to sell to Chinese buyers in the wake of the 2019 coronavirus outbreak, or a similar situation, there are laws and government bodies that must be navigated.
  • Getting supplies. Currently there are mask material shortages, especially with melt-blown fabric. A single melt-blow machine can take months to make and install due to its need to consistently produce an extremely precise product. Because of this it has been difficult for melt-blown fabric manufacturers to scale up, and the massive global demand for masks made from this fabric has created shortages and price hikes.

Sourcing for Mask Materials

While materials for surgical masks have undergone shortages due to the ongoing pandemic, open-source patterns and instructions for masks made of more common materials have been popping up across the internet. Although these are meant for DIYers, they can also be used as a starting point for commercial patterns and production. We’ve found three mask pattern examples and provided links to sourcing categories on Thomasnet.com to help you get started.

Regional Medical Center

The Olson Mask: This mask is designed to be donated to hospitals, which will add the hair ties and waxed string for a better fit to the individual healthcare worker, as well as inserting the .3 micron filter.

FreeSewing.org

The Fu Face Mask: This website includes an instruction video for how to make this face mask. The pattern requires you to measure the circumference of your head.

Sew It Online

Cloth Mask Pattern: Sew It Online’s mask includes the pattern design on the instructions. Once the user prints the instructions out, they can simply cut out the pattern and start working.

Conclusion

Now that we’ve outlined details on the types of surgical masks, how surgical masks are made, and challenges to companies trying to break into the field, we hope this will enable you to source more effectively. If you’re ready to start shortlisting suppliers, we invite you to check out our Supplier Discovery page, which has detailed information on over 90 suppliers of surgical masks.

The purpose of this document is to collect and present research on the way surgical masks are manufactured. While we endeavor to curate and create the most up-to-date information, please note that we cannot guarantee 100% accuracy. Please also note that Thomas does not provide, endorse, or guarantee any third-party product, service or information. Thomas is not affiliated with the vendors featured on this page and is not responsible for their products and services. We are not responsible for the practices or the content of their websites and apps.

Sources:

  1. Journal of Academia and Industrial Research
  2. Textile Learner
  3. Nonwovens Excellence Platform
  4. Nelson Labs
  5. ASTM
  6. Canadian Centre for Occupational Health and Safety
  7. Becker’s Hospital Review
  8. Crosstex
  9. Infection Control Products
  10. NPR
  11. U.S. National Library of Medicine
  12. New York Times
  13. Entrepreneur India
  14. Nonwoven Tools

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N95 Masks vs. Surgical Masks vs. Cloth Masks


Il n’y a pas si longtemps, les respirateurs et les masques chirurgicaux étaient portés presque exclusivement par les travailleurs dont le travail les exigeait. Mais pendant la pandémie de COVID-19, de nombreux types de protections faciales sont devenues de plus en plus courantes dans les lieux publics. Leur visibilité soulève une question évidente: quelle est la différence entre les masques N95 vs masques chirurgicaux vs respirateurs vs masques anti-poussière vs masques en tissu? Quel type de protection offrent-ils?

Masques en tissu

Les Centers for Disease Control and Prevention (CDC) ont recommandé que les personnes porter des revêtements faciaux en tissu en public pour aider à prévenir la propagation du COVID-19, indépendamment du fait qu’ils aient de la fièvre ou d’autres symptômes du COVID-19. Il existe des preuves que le COVID-19 peut être transmis par des personnes qui ne présentent pas de symptômes. Le port de masques en tissu aide à ralentir la propagation du virus, qui se transmet principalement d’une personne à l’autre par les gouttelettes respiratoires produites lorsque nous parlons, toussons ou éternuons. Le CDC recommande des revêtements faciaux en tissu dans les magasins et autres endroits où distanciation sociale est difficile à maintenir, en particulier dans les zones où la transmission communautaire est importante.

  • Bien que les masques en tissu puissent aider à prévenir la propagation du COVID-19 et d’autres maladies, ils ne sont pas considérés comme des équipements de protection individuelle (EPI).
  • Les masques en tissu sont destinés à être nettoyés et réutilisés, contrairement aux masques chirurgicaux et aux respirateurs jetables N95.
  • Les masques en tissu sont faciles à obtenir et simples à fabriquer à la maison. D’autre part, les masques chirurgicaux et les respirateurs N95 ne peuvent pas être fabriqués à la maison et devraient être considérés comme des fournitures essentielles, selon le CDC.

Masques chirurgicaux

Les masques chirurgicaux (également appelés masques médicaux) sont des revêtements amples et jetables pour le nez et la bouche. Ils sont destinés à être portés par les agents de santé. Ils résistent aux fluides et protègent le porteur contre les grosses gouttelettes, les éclaboussures et les sprays, D’après le CDC. Ils captent également les gouttelettes respiratoires du porteur, aidant à protéger les patients contre la contamination.

  • Les masques chirurgicaux ne sont pas considérés comme une protection respiratoire. Selon le CDC, ils n’offrent pas une protection fiable contre l’inhalation de plus petites particules en suspension dans l’air.
  • Les masques chirurgicaux sont autorisés pour une utilisation en milieu médical par la Food and Drug Administration (FDA), qui évalue les données et les allégations fournies par le fabricant du masque.
  • Les masques chirurgicaux sont testés selon les normes publiées par ASTM International comme ASTM F2100-19. Ces normes décrivent l’efficacité de la filtration bactérienne, l’efficacité de la filtration des particules submicroniques, la pression différentielle, la résistance au sang synthétique et l’inflammabilité. Les masques médicaux se divisent en trois niveaux de protection barrière, qui sont décrits ci-après par société de services de santé Cardinal Health:
    • Niveau 1: protection barrière basse
    • Niveau 2: protection barrière modérée
    • Niveau 3: protection maximale de la barrière

Respirateurs N95

Les respirateurs N95 sont généralement jetables et sont communément appelés respirateurs à masque filtrant. OSHA définit un respirateur à masque filtrant comme “un respirateur à particules à pression négative avec un filtre faisant partie intégrante de la pièce faciale ou avec la pièce faciale entière composée du milieu filtrant”.

  • Les masques filtrants N95 offrent une meilleure protection contre les particules en suspension que les masques chirurgicaux ou les masques en tissu, car ils sont conçus pour être bien ajustés et peuvent filtrer les grandes et petites particules, y compris les aérosols.
  • Les masques N95 sont testés et certifiés par le National Institute of Occupational Safety and Health (NIOSH) pour garantir que le masque filtrant peut éliminer au moins 95% des particules en suspension dans l’air.
  • N95 sont conçus pour être bien ajustés. Normalement, les utilisateurs doivent réussir un test d’ajustement pour confirmer une bonne étanchéité avant d’en utiliser un. En raison des préoccupations concernant une pénurie de kits de test d’ajustement et de solutions de test, l’OSHA encourage les employeurs à donner la priorité aux tests d’ajustement pour ceux qui doivent utiliser des respirateurs N95 dans des procédures à haut risque pendant la pandémie de COVID-19.
  • Certains fabricants proposent des respirateurs chirurgicaux à masque filtrant N95, qui sont approuvés par la FDA pour la résistance aux fluides et également testés et certifiés par NIOSH comme respirateur.
  • Les respirateurs N95 ne doivent pas être portés par le grand public comme protection contre le COVID-19 selon le CDC, pour aider à optimiser l’approvisionnement pour les respirateurs les plus humains.

Respirateurs élastomères: une alternative N95

Les respirateurs élastomères réutilisables, plus couramment observés dans les environnements industriels, peuvent fournir une protection similaire aux respirateurs jetables N95, selon le CDC, qui propose conseils sur les respirateurs élastomères pour les professionnels de la santé. Les respirateurs élastomères peuvent avoir un demi-masque ou un masque complet, et ils utilisent des filtres remplaçables pour éliminer les particules de l’air. Ils nécessitent également un nettoyage, une désinfection et d’autres travaux d’entretien. Contrairement aux masques chirurgicaux, les respirateurs élastomères ne sont pas approuvés par la FDA pour la résistance aux fluides.

Masques anti-poussière et autres revêtements faciaux jetables

L’expression «masque anti-poussière» est utilisée par certaines personnes pour décrire tout masque facial jetable, y compris les respirateurs N95. Mais les masques antipoussières ne sont pas nécessairement les mêmes que les respirateurs et sont souvent conçus pour protéger le porteur uniquement des irritants non toxiques, comme la sciure ou le pollen. Ces «masques antipoussières nuisibles» ne sont ni testés ni certifiés par NIOSH pour offrir un quelconque niveau de filtration respiratoire. Les directives du CDC ne traitent pas des masques antipoussières nuisibles, et il n’y a aucune raison de croire qu’un masque antipoussière non certifié NIOSH offrirait une protection respiratoire supérieure à celle d’un masque en tissu.

De même, il existe des revêtements faciaux jetables qui ressemblent à des masques chirurgicaux ou à des masques médicaux, mais qui ne sont pas testés pour la protection de la barrière selon les normes ASTM et ne sont pas autorisés à être utilisés dans les milieux médicaux par la FDA.

Conseils pour porter des masques en tissu

Ces conseils pour le port de masques en tissu sont basés sur les informations du CDC et de la Mayo Clinic:

  • Ne touchez pas votre masque lorsque vous le portez. Si vous le touchez, lavez ou désinfectez vos mains.
  • Lorsque vous retirez votre masque, ne touchez pas votre visage, en particulier votre nez, vos yeux et votre bouche, ni l’avant du masque.
  • Après avoir retiré votre masque, lavez-vous les mains immédiatement.
  • Nettoyez régulièrement votre masque dans une machine à laver.
  • Fabriquez ou recherchez des masques en tissu qui ont plus d’une couche de tissu.
  • Assurez-vous que les masques en tissu couvrent le nez et la bouche et sont fixés avec des attaches ou des boucles d’oreille, bien ajustés mais confortablement.
  • N’oubliez pas que si le port d’un masque en tissu est une précaution importante contre la propagation du COVID-19, il est toujours important de se laver les mains fréquemment et de suivre les directives de distanciation sociale.
  • N’oubliez pas que les masques en tissu ne remplacent pas la protection respiratoire requise.



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Face Masks and Surgical Masks for COVID-19: Manufacturing, Purchasing, Importing, and Donating Masks During the Public Health Emergency


masque chirurgical - masques faciaux et masques chirurgicaux pour COVID-19

En général, les masques sont utilisés par le grand public et le personnel de santé pour empêcher la propagation d’une infection ou d’une maladie.

Cette page est destinée aux personnes et aux organisations qui travaillent pour la première fois avec la FDA. Pour aider à élargir la disponibilité des masques faciaux et des masques chirurgicaux, la FDA offre une flexibilité réglementaire, comme décrit dans notre politique pour les masques faciaux et les masques chirurgicaux qui est en vigueur pendant la pandémie COVID-19.

Si vous êtes intéressé par la fabrication de ces produits, nous vous exhortons à consulter l’autorisation d’utilisation d’urgence (EUA) de la FDA pour masques faciaux (PDF-98KB) (publié le 24 avril 2020) et la politique de la FDA sur masques faciaux et masques chirurgicaux en vigueur pendant l’urgence de santé publique COVID-19, et lisez les informations sur cette page. Vous pouvez envoyer des questions spécifiques à CDRH-COVID19-SurgicalMasks@fda.hhs.gov.

Q: Quels masques sont les appareils médicaux réglementés par la FDA?

A. Les masques faciaux commercialisés auprès du grand public à des fins générales non médicales, telles que l’utilisation dans la construction et d’autres applications industrielles, ne sont pas des dispositifs médicaux. Les masques faciaux, lorsqu’ils sont destinés à un usage médical tel que le contrôle à la source (y compris les utilisations liées au COVID-19) et les masques chirurgicaux sont des dispositifs médicaux.

Q: Y a-t-il une différence entre un masque et un respirateur?

UNE: Masques et respirateurs les deux couvrent le nez et la bouche du porteur, mais ils diffèrent sur plusieurs aspects.

Les masques sont amples et peuvent ne pas offrir une protection complète contre l’inhalation d’agents pathogènes en suspension dans l’air, tels que les virus.

  • Masques faciaux (masques non chirurgicaux) peut ne pas fournir de protection contre les fluides ou ne pas filtrer les particules, nécessaires pour se protéger contre les agents pathogènes, tels que les virus. Ils ne sont pas destinés à un usage chirurgical et ne sont pas considérés comme des équipements de protection individuelle.
  • Masques chirurgicaux sont des dispositifs résistants aux fluides, jetables et amples qui créent une barrière physique entre la bouche et le nez du porteur et l’environnement immédiat. Ils sont destinés à être utilisés en milieu chirurgical et ne fournissent pas une protection complète contre l’inhalation d’agents pathogènes en suspension dans l’air, tels que les virus.

Les respirateurs sont des équipements de protection individuelle qui s’adaptent étroitement au visage et filtrent les particules en suspension pour protéger les travailleurs de la santé. Ils offrent un niveau de protection plus élevé contre les virus et les bactéries lorsque correctement ajusté. Ce document ne traite pas des respirateurs.

Ce Infographie CDC explique les différences entre les masques chirurgicaux et les respirateurs N95.

Q: Je suis intéressé par la fabrication de masques faciaux pour COVID-19. Qu’est-ce que je dois faire?

R: Cela dépendra du type de masque que vous souhaitez fabriquer.

Les masques à usage non médical ne sont pas des dispositifs médicaux et ne sont pas réglementés par la FDA.

La FDA a publié un EUA pour les masques faciaux qui répondent à certains critères, y compris les revêtements faciaux en tissu recommandés par les Centers for Disease Control (CDC). Pendant l’urgence de santé publique COVID-19, un masque facial à usage médical qui est destiné à être utilisé comme contrôle à la source, n’est pas étiqueté comme masque chirurgical et n’est pas destiné à fournir une protection contre les liquides, peut être autorisé en vertu de la “parapluie” EUA pour les masques faciaux sans soumettre de documentation à la FDA si le masque facial répond aux critères d’éligibilité. Un masque facial autorisé en vertu de cet EUA doit être conforme aux conditions d’autorisation (section IV) de l’EUA. Veuillez noter que cet EUA n’autorise pas l’utilisation des masques faciaux comme équipement de protection individuelle.

En plus de l’EUA «parapluie» pour les masques faciaux, comme décrit dans la politique de la FDA sur masques faciaux et masques chirurgicaux en vigueur pendant l’urgence de santé publique COVID-19, la FDA ne s’attend pas à ce que les fabricants de masques faciaux à usage médical qui ne sont pas destinés à fournir une protection contre les liquides présentent une notification à la FDA avant de commencer à commercialiser leur produit, ou à se conformer à certaines exigences réglementaires, lorsque le masque facial ne le fait pas. créer un risque indu à la lumière de l’urgence de santé publique.

En vertu de cette politique, la FDA estime que les masques faciaux non destinés à fournir une protection contre les liquides ne créent pas un tel risque indu lorsque:

  • Les masques faciaux incluent un étiquetage qui:
    • Décrit avec précision le produit comme un masque facial (par opposition à un masque chirurgical ou à un respirateur à masque filtrant);
    • Comprend une liste de matériaux en contact avec le corps (qui n’inclut aucun médicament ou produit biologique); et
    • Comprend des recommandations et des déclarations générales qui réduiraient le risque d’utilisation. Par exemple, des recommandations contre l’utilisation:
      • Dans tout cadre chirurgical ou dans les cas où une exposition significative à des liquides, corporels ou autres liquides dangereux peut être attendue;
      • Dans un environnement clinique où le niveau de risque d’infection par inhalation est élevé;
      • En présence d’une source de chaleur à haute intensité ou d’un gaz inflammable;
  • Les masques faciaux ne sont pas destinés à un usage qui créerait un tel risque indu. Par exemple, l’étiquetage n’inclut pas les utilisations pour la protection antimicrobienne ou antivirale, la prévention ou la réduction des infections ou les utilisations connexes, et n’inclut pas les allégations de filtration des particules.

Q: Je suis intéressé par la fabrication de masques chirurgicaux pour COVID-19. Qu’est-ce que je dois faire?

Lors de l’urgence de santé publique COVID-19, et comme décrit dans la politique de la FDA sur les masques faciaux et les masques chirurgicaux qui est en vigueur pendant l’urgence de santé publique COVID-19, la FDA ne s’attend pas à ce que les fabricants de masques chirurgicaux destinés à fournir une protection contre les liquides de soumettre une notification à la FDA avant de commencer la commercialisation de leur produit, ou de se conformer à certaines exigences réglementaires lorsque les masques chirurgicaux ne créent pas de risque indu à la lumière de l’urgence de santé publique.

En vertu de la politique, la FDA estime que les masques chirurgicaux destinés à fournir une protection contre les liquides ne créent pas de risque indu lorsque:

  • Les masques chirurgicaux répondent à des performances de barrière aux liquides conformes à Norme ASTM F1862 et l’exigence d’inflammabilité de classe I ou de classe II selon 16 CFR partie 1610 (sauf si étiqueté avec une recommandation contre l’utilisation en présence d’une source de chaleur de haute intensité ou d’un gaz inflammable);
  • Les masques chirurgicaux comprennent un étiquetage qui décrit avec précision le produit comme un masque chirurgical et comprend une liste des matériaux en contact avec le corps (qui ne comprennent aucun médicament ou produit biologique); et
  • Les masques chirurgicaux ne sont pas destinés à un usage qui créerait un tel risque indu. Par exemple, l’étiquetage n’inclut pas les utilisations pour la protection antimicrobienne ou antivirale, la prévention ou la réduction des infections ou les utilisations connexes, et n’inclut pas les allégations de filtration des particules.

Q: Je souhaite importer des masques pour COVID-19. Qu’est-ce que je dois faire?

R: Pour éviter les retards d’envois légitimes, nous exhortons les importateurs à examiner Importation de fournitures pour COVID-19 et instructions aux importateurs pour des informations importantes sur l’importation de produits, y compris les masques faciaux et les masques chirurgicaux, afin de garantir que la documentation appropriée est soumise au moment de l’entrée. La FDA est prête et disponible pour s’engager avec les importateurs afin de minimiser les perturbations pendant le processus d’importation. Si vous avez des questions concernant le processus d’importation général, vous pouvez envoyer un e-mail COVID19FDAIMPORTINQUIRIES@fda.hhs.gov. Si vous avez des questions concernant une entrée active, veuillez contacter le bureau de la FDA couvrant votre port d’entrée en visitant le Page Bureaux d’importation et port d’entrée de la FDA.

Q: Je souhaite acheter des masques pour COVID-19. Comment savoir s’ils sont contrefaits ou frauduleux?

R: La FDA ne délivre aucun type de certification pour démontrer qu’un fabricant est en conformité avec les exigences de la FDA.

La FDA n’a pas de liste exhaustive de tous les produits contrefaits ou frauduleux. Pour signaler les produits COVID-19 frauduleux à la FDA, veuillez envoyer un e-mail FDA-COVID-19-Fraudulent-Products@fda.hhs.gov.

Q: Je voudrais acheter des masques pour les travailleurs de la santé pendant la pandémie COVID-19. Comment puis-je les obtenir?

R: La FDA n’a pas de liste de fournisseurs de masques. Si vous êtes un établissement de santé, consultez votre fournisseur, distributeur ou votre service de santé local.

Q: J’aimerais faire don de masques aux travailleurs de la santé pendant la pandémie COVID-19. Comment pouvez-vous m’aider avec mon don?

R: La FDA n’achète ni ne distribue de masques. Si vous souhaitez faire un don de masques, veuillez consulter COVID-19 Offre de fournitures ou d’équipements médicaux.

Q: Je voudrais réutiliser les masques pendant la pandémie COVID-19. Qu’est-ce que je dois faire?

R: En cette période de forte demande de masques, il y a stratégie de conservation pour atténuer les pénuries de masques.

Q: Un masque peut-il prétendre être conforme à une norme d’efficacité de filtration du National Institute for Occupational Safety and Health (NIOSH)?

R: Non. Les masques ne peuvent prétendre répondre à une norme d’efficacité de filtration NIOSH. De telles allégations ne peuvent être faites que pour un respirateur, lorsque le respirateur atteint une efficacité de filtration spécifiée.

Prochaines étapes

Si vous êtes toujours intéressé par la fabrication de masques faciaux et / ou de masques chirurgicaux à utiliser pendant la pandémie COVID-19, consultez ces documents:

Documents de la FDA

Autres documents



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