What are Masks and N95 Respirators?
About Facemasks and N95 Respirators
Facemasks and N95 respirators protects the person who wears it from contamination. They act as an individual protective gear for people who could come in contact with infections or dust that are airborne or in liquid form.
A facemask fits comfortably over a person’s nose and mouth and obstructs any contamination or infection from affecting. They can be disposed after every use, hence must not be shared. Facemasks usually are for medical and research purposes, widely used during procedures, surgeries, lab experiments etc.
Every Facemask is different, the quality and thicknesses of the facemasks may vary based on the purpose it is used for, and like a thicker and better quality facemask will give you far better protection.
Apart from the quality of the facemask, wearing the mask properly to completely cover your mouth and nose is effective in protecting oneself from viruses, germs, bacteria that are spread. The facemasks are capable of protecting one from exposure in the form of small to large droplets or sprinkles through saliva or respiratory emission.
However, a facemask cannot filter very small airborne droplets that get transmitted when someone coughs or sneezes. Since the facemasks have a loose fitting, they do not entirely protect a person from infections and contaminations.
While a facemask may be effective in blocking splashes and large-particle droplets, a facemask, by design, does not filter or block very small particles in the air that may be transmitted by coughs, sneezes or certain medical procedures. Facemasks also do not provide complete protection from germs and other contaminants because of the loose fit between the surface of the facemask and your face.
Since Facemasks are a onetime use product, if found damaged or soiled it must be immediately and safely discarded in a sealed plastic bag in a trash bin. Sanitize your hands or wash them thoroughly with alcohol based soap after handling the mask.
A N95 respirator is an ideal protective equipment against airborne contamination particles of any size used usually in construction and industrial businesses. It is comfortable to breathe since it fits perfectly on the face covering your mouth and nose.
The ‘N95’ name is given to it because it can protect the wearer against 95% of very small particles (nearly 0.3 micron), provided it is properly worn. However, a N95 respirator cannot completely negate the risk of falling sick or death even after wearing it properly.
The design for N95 respirators is not an all-fit one, hence are not meant for children or people with facial hair or beard and may not completely protect against viruses or infections.
N95 Respirators Used by General Public
According to the FDA or Food and Drug Administration, US, and the CDC or the Centers for Disease Control and Prevention have a set guideline on general public using N95 Respirators only during health emergencies. They may be appropriate for people who could be at high risk of falling sick from influenza or other respiratory diseases and infections like Coronaviruses. However, your health care provider would be the best person to provide information about its use.
The following are the N95 Respirators approved by the FDA for Public Use only in case of Health and Medical Emergencies: (Note: these are not for Occupational Use)
- 3M™ Particulate Respirator 8670F
- 3M™ Particulate Respirator 8612F
- Pasture Tm F550G Respirator
- Pasture Tm A520G Respirator
N95 Respirators in Industrial and Health Care Settings
The National Personal Protective Technology Laboratory (NPPTL) in the National Institute for Occupational Safety and Health (NIOSH), which is part of the Centers for Disease Control and Prevention (CDC) regulates some N95 respirators that are labeled as “For Occupational Use” are used for construction and other industrial type jobs where workers are highly exposed to dust and small particles. These products are labeled "For occupational use."
There are also some N95 respirators that are used in the healthcare setting. These Class II disposable protective gear are regulated by the FDA and are essentially for single-use only, worn by healthcare personnel during medical procedures. This gear protects the patient and healthcare personnel against transmission of harmful microorganisms, body fluids, and very small particles or material. The FDA regulation of the N95 Respirator is under 21 CFR 878.4040, and CDC NIOSH, terms and conditions apply.
General N95 Respirator Precautions
N95 Respirators can make breathing difficult for people who suffer from chronic respiratory, cardiac, or other medical conditions and hence must check with a health personnel before using it. Some models also possess exhalation valves to help heat build-up when breathing out (In Sterile conditions, models with exhalation valves must not be used).
N95 respirators that are cleared by the FDA are labeled as "single use", disposable gear. If the respirator is found damaged or soiled, it must be safely thrown in a sealed plastic bag in a trash bin. Once you do that it is advisable to immediately sanitize your hands or wash them thoroughly with an alcohol based soap.
Standard Specification for Efficiency and Test Performance of Materials Used in Face Masks And Respirators
ASTM F2100, F2101 and EN 14683
Bacterial & Viral Filtration Efficiency (BFE/VFE)
The Bacterial Filtration Efficiency (BFE) test is performed on materials and gear used to filter. They are specifically designed to protect against biological aerosols, such as face masks, surgical gowns, caps, and air filters.
This test is used for FDA 510(k) submissions for surgical masks, is required by ASTM F2100 and EN 14683, and in compliance with ASTM F2101 and EN14683.
Bacterial Filtration Efficiency (BFE)
The Bacterial Filtration Efficiency test checks the filtration efficiency where comparison is made between bacterial control counts and test article effluent counts using the challenge organism, Staphylococcus aureus. After the filtration media is brought into the desired condition the liquid form of Staphylococcus aureus is aerosolized at a constant flow rate of 28.3 liters per minute (LPM) or 1 cubic foot per minute (CFM).
The aerosol droplets are then drawn and collected using an Andersen sampler (that uses six stages). Further challenge controls and tests are conducted to determine the number of bacterial aerosol droplets that are in contact with the filter media. Challenge controls are held at 1700 – 3000 colony-forming units (CFU) where the mean particle size (MPS) is 3.0 ± 0.3 µm that is controlled using Andersen sampler where analysis is conducted at every stage, allowing filtration efficiencies to be up to >99.9%.
Advantages of BFE Test:
- The BFE test has more advantages over other filtration efficiency tests.
- It is used as a standard reference test since many years where comparison of filtration materials is carried out.
- It uses Andersen Sampler
- The procedure can be reproduced
- It can pose a serious challenge to most other filtration devices.
- In a short time period, large numbers of materials can be evaluated.
BFE testing is commonly performed along with the Differential Pressure (Delta P) test.
Alternatively, Increased Challenge BFE method is used for housed filters, where the challenge organism delivered is at a higher concentration to each test material. Filtration efficiency measurements can be up to >99.9999%.
Increased Challenge Bacterial Filtration Efficiency (BFE)
The Increased Bacterial Filtration Efficiency test determines the filtration efficiency where the bacterial control counts to test article effluent counts are compared. Here again the challenge organism is liquid Staphylococcus aureus that is aerosolized for a minute interval and sent to the filtration media at a constant flow rate of 30 liters per minute (LPM).
The aerosol droplets are collected in chambers that are all-glass impingers (AGIs). The sample is collected through the AGIs for two minutes in order to clear the aerosol chamber. To determine the titer of the test fluid, techniques like standard plate count and/or membrane filtration are used. To determine the number of bacterial aerosol droplets contacting the filter media, challenge controls without filter media are used, where the challenge controls are maintained at ≥ 1 x 106 colony-forming units (CFU) and a mean particle size (MPS) of 3.0 ± 0.3 µm. This makes sure filtration efficiencies are up to >99.9999%.
Advantages of the Increased BFE Test:
- It is more advantageous over other filtration efficiency tests.
- It has been used for years without any variations and is used as a standard reference to compare filtration materials.
- It can be reproduced and easily conducted
- It poses a serious challenge to most commonly filtration devices.
Viral Filtration Efficiency (VFE)
The procedure followed in the Viral Filtration Efficiency (VFE) test is same as in BFE, except the challenge organism used here is the bacteriophase phiX174.
During the tests, the challenge controls are maintained at 1100-3300 plaque-forming units (PFU) where a mean particle size (MPS) is 3.0 ± 0.3 µm, this makes sure the filtration efficiencies can be up to >99.9%.
Increased Challenge Virus Filtration Efficiency (VFE)
The Increased VFE test also follows the same efficiency procedure as in BFE, however the challenge organism used is the bacteriophase phiX174.
Here the challenge controls are maintained at ≥1×106 plaque-forming units (PFU) and a mean particle size (MPS) of 3.0 ± 0.3 µm. This permits filtration efficiencies to be reported up to >99.9999%
(Information courtesy: Nelson Labs, USA)