N95 mask

from Wikipedia, the free encyclopedia
N95 mask

An N95 mask is a particulate filtering respirator that meets the N95 standard of air filtration rating of the U.S. National Institute for Occupational Safety and Health (NIOSH). This means that at least 95% of the particles in the air that are larger than 0.3 µm are separated. The letter N indicates that the mask, unlike the P95 mask, is not resistant to oily aerosols. It is the most commonly used particle-filtering respirator of the seven American classification levels. This type of respirator protects against particles , but not gases or vapors .

N95 respirators are considered functionally equivalent to certain respirators that are regulated in countries outside of the United States , e.g. B. FFP2 respirators that meet the European standard and KN95 respirators from China. However, slightly different criteria are used to certify their performance, e.g. B. Filter efficiency, test media and flow rate, and allowable pressure drop.

The N95 mask consists, among other things, of a fine-meshed network of synthetic polymer fibers , also known as non-woven fabric made of polypropylene , which forms the inner filtration layer that holds back particles. This filter fleece is produced using the meltblown process , a modified form of melt spinning .

history

In the 1970s, the Bureau of Mines and NIOSH in the United States set American standards for disposable particulate matter masks. The first N95 mask was developed by the technology group 3M and approved in 1972. Initially designed as a dust mask for industrial use, it was increasingly used in the healthcare sector in the 1990s to protect against infection.

Usage

In the USA, the Occupational Safety and Health Administration (OSHA) requires health care workers who care for COVID-19 patients or suspected patients to wear respiratory masks, such as N95 protective masks. In contrast to an N95 mask, mouth and nose protection does not adequately protect the wearer from particles in the air, such as B. from viruses, as it does not seal the mouth and nose area airtight.

Respirator fit tests are an important component of a respiratory protection program when employees are using close-fitting respirators. OSHA requires an initial respirator fit test to determine the right model, style, and size for each employee, as well as annual fit tests. In addition, close-fitting respirators, including the N95, require a simple fit test by the user each time they are put on.

Use in case of bottlenecks

In crisis situations in which there is a lack of N95 protective masks, such as the COVID-19 pandemic , the Centers for Disease Control and Prevention (CDC) have recommended strategies to optimize their use in American healthcare. N95 respirators can continue to be used beyond the manufacturer's recommended wearing time, although components such as the straps and nasal bridge material will wear out, which can affect the quality of fit and sealing properties. Therefore, it is expected that the wearer perform a fit test prior to use. Respirators approved according to standards in other countries and similar to NIOSH approved N95 respirators, including the European Union Regulated FFP2 and FFP3, may also be used. N95 respirators can be reused after they have been removed, but the number of subsequent uses is limited. In addition, the mask must not have been exposed to aerosol exposure and must not be contaminated with the patient's body fluids. Repeated use increases the risk of surface contamination with pathogens. The respirator manufacturer can recommend a maximum number of uses. If no manufacturer guidelines are available, it is recommended that use be limited to five applications per mask to ensure adequate safety margins. Part of the type test for N95 masks is heating to 71 ° C for 48 hours. Disinfection at this temperature is therefore also possible without damaging the masks.

Other protective masks

A surgical mask (full face mask , MNS) is a loose fitting, disposable mask that creates a physical barrier between the wearer's mouth and nose and potential contaminants in the immediate area. When worn properly, a surgical mask is designed to help block droplets, splashes, sprays, or splashes containing large particles that may contain viruses and bacteria . Surgical masks can also help protect nearby people from the wearer's saliva and respiratory secretions.

The filtration performance of a surgical mask, which as a medical product is subject to the EN 14683: 2019 standard within the European Union, has an identical (type I, 95% separation performance) or better (type II, 98% separation performance) filtration effect than N95 masks. Their disadvantage, however, lies in the sealing: With surgical masks, breathing air can enter and exit the mask much more easily. They therefore do not offer complete protection against germs and other contaminants.

The US Centers for Disease Control and Prevention (CDC) recommend a protective visor that completely covers the face, including a protective mask , for procedures that can generate aerosols - such as suctioning the airways or bronchoscopy with an integrated visor or a half mask combined with protective goggles. The CDC recommends the use of respirators with at least N95 certification to the wearer from inhaling infectious particles such as mycobacteria , bird flu and other influenza viruses , SARS and Ebola viruses to protect.

Web links

Commons : N95 mask  - collection of images, videos and audio files

Individual evidence

  1. ↑ NIOSH-Approved N95 Particulate Filtering Facepiece Respirators - A Suppliers List ( en-us ) March 19, 2020. Retrieved March 27, 2020.
  2. ↑ Respirator Trusted Source: Selection FAQs ( en-us ) March 12, 2020. Accessed March 28, 2020.
  3. ↑ Comparison of FFP2, KN95, and N95 and Other Filtering Facepiece Respirator Classes . January 1, 2020. Accessed March 28, 2020.
  4. ↑ a b c d e Strategies for Optimizing the Supply of N95 Respirators: Crisis / Alternate Strategies ( en-us ) March 17, 2020. Retrieved March 28, 2020.
  5. ↑ John Zie: World Depends on China for Face Masks But Can Country Deliver? . In: Voice of America , March 19, 2020. 
  6. ↑ Emily Feng: COVID-19 Has Caused A Shortage Of Face Masks. But They're Surprisingly Hard To Make . In: National Public Radio , March 16, 2020. 
  7. ^ Meltblowing. LSP Chair for Polymer Materials, FAU Erlangen; accessed on April 19, 2020
  8. ↑ a b Mark Wilson: The untold origin story of the N95 mask ( en-US ) March 24, 2020. Retrieved March 27, 2020.
  9. ^ A b Maryann M. D'Alessandro, Jaclyn Krah Cichowicz: Proper N95 Respirator Use for Respiratory Protection Preparedness ( en-us ) March 16, 2020. Retrieved March 27, 2020.
  10. ↑ Release of Stockpiled N95 Filtering Facepiece Respirators Beyond the Manufacturer-Designated Shelf Life: Considerations for the COVID-19 Response ( en-us ) February 28, 2020. Accessed March 28, 2020.
  11. ↑ Recommended Guidance for Extended Use and Limited Reuse of N95 Filtering Facepiece Respirators in Healthcare Settings ( en-us ) March 27, 2020. Accessed March 28, 2020.
  12. ↑ Code of Federal Regulations, Title 42: Public Health, Part 84: Approval of respiratory protective devices, p. 675. ( en-us ) October 1, 2019.
  13. ↑ a b N95 Respirators and Surgical Masks (Face Masks) ( en ) March 11, 2020. Retrieved March 28, 2020.
  14. ^ Isolation Precautions . July 22, 2019. Accessed February 9, 2020.
  15. ↑ 2007 Guideline for Isolation Precautions: Preventing Transmission of Infectious Agents in Healthcare Settings . US Centers for Disease Control and Prevention. Pp. 55-56. July 2019. Accessed February 9, 2020.