If you’ve done any kind of research into safety masks, you’ve probably come across various names that combine letters and numbers. While most doctors and nurses know the differences between these masks by heart, this knowledge is less common in the general populace. So, in this guide, we will take a look at the differences between two of the most common types of medical-grade safety masks: N95 masks and KN95 masks.

Medical-Grade Masks: A Brief Introduction


There are many different types and varieties of medical-grade masks. Some are designed for low-risk procedures, while others are designed to protect the wearer in high-risk environments. For example, a standard surgical mask is designed to provide a high degree of filtration and fluid splatter protection. However, N95 masks, sometimes known as “respirators,” are more complex devices that provide even higher levels of protection.

N95 Masks: Health Standards, Characteristics, and Usage


The regulation of N95 masks is managed by several federal and private agencies in the United States, including the National Institute for Occupational Safety and Health (NIOSH), a division of the CDC, the American Society for Testing and Materials (ASTM), as well as the U.S. Food & Drug Administration (FDA). Together, these agencies and organizations conduct the research and testing necessary to provide medical workers with high-quality Personal Protective Equipment (PPE). N95 masks are merely one example of PPE, though they happen to be one of the most important devices in the fight against COVID-19.

N95 Mask Testing


N95 mask manufacturers must meet the health and safety standards set out by the agencies listed above. Generally speaking, N95 masks are tested based on the following criteria:


  • Fluid resistance - This refers to a mask or material’s ability to repel or absorb fluids.
  • Filtration efficiency (particulate and bacterial) - This refers to a mask or material’s ability to filter out particles of varying sizes, as well as airborne bacteria.
  • Flammability - This refers to a mask or material’s ability to resist flames.
  • Biocompatibility - This refers to a mask or material’s level of toxicity (or propensity to cause injury).

There are a variety of tests established by NIOSH to determine if masks meet the necessary requirements. Nelson Labs expounds on these tests in the passage below: 


“Masks intended for respirator precertification may require NaCl, DOP, valve leak, and inhalation/exhalation tests to verify conformity to NIOSH standards. Nelson Labs offers precertification testing services for these tests.


The Sodium Chloride Aerosol Challenge (NaCl) – NIOSH Respirator Prequalification test uses a widely accepted method for evaluating particle penetration and air flow resistance properties of a variety of filtration materials. Respirators must be prequalified before submitting to NIOSH for certification; other materials, such as breathing system filters and face masks, are tested to determine filtration efficiency for marketing. These tests are performed for masks seeking N95 respirator precertification.


The Dioctyl Phthalate (DOP) test is used to evaluate particle penetration and air flow resistance properties for a variety of filtration materials, including HEPA filters, NIOSH respirators, and filter media. The test is performed in compliance with 42 CFR Part 84 and NIOSH Procedure No. RCT-APR-STP-0051-0056, 2005 and is necessary for prequalification for NIOSH certification of respirators. Nelson Labs has extensive experience testing filters and other filtration devices.


Testing is performed in compliance with 42 CFR Part 84 and NIOSH Procedure No. RC-APR-STP-0057, 0058 and 0059. Nelson Labs has extensive experience testing filters and other filtration devices.”


As you can see, the testing of N95 masks is thorough and rigorous. N95 masks are expected to protect users from almost any kind of airborne particle or fluid penetration. Thus, the safety standards are taken very seriously and only compliant manufacturers are allowed to take their products to market.

N95 Mask Characteristics


N95 masks are relatively unique in both their physical characteristics and functionality. A traditional surgical mask is malleable and does not fit tightly against the face. Alternatively, an N95 mask has a hard, shell-like exterior made of tightly-woven polypropylene fiber. Additionally, most N95 masks include extra features like a nose clip and a valve. The nose clip ensures that the area around the bridge of the nose remains tight against the skin, while a valve is an optional feature that allows for greater breathability. 


Just like surgical masks, N95 masks are not designed to be reused. Once exposed to an environment with contaminates for more than a few hours, N95 masks must be properly disposed of and replaced. This applies to both regular users and medical workers.

How to Use N95 Masks


Unbeknownst to many people, there is a correct way to apply and use N95 masks. If you need to put on an N95 mask, you should practice the following steps:


  1. Hold the N95 mask in your hands with the front of the mask (exterior) facing downwards. Your fingertips should be placed on the nosepiece.
  2. Place the respirator on your face with the straps hanging down. Position the mask so that it fully covers your nose and chin (be sure not to touch the interior of the mask with your hands).
  3. Pull the straps behind your head. The top strap should fit around the back of your head, while the bottom strap should be placed at the top of your neck. Do not allow the straps to cross one another.
  4. Use your fingers to mold the metallic nosepiece so that it fits the shape of your nose. It should feel tight (though not uncomfortable) against the bridge of your nose. This ensures that the nosepiece can form a seal against your skin.
  5. To test your N95 mask, cup both hands over the mask and begin to inhale and exhale strongly. If you can feel air leaking around the edges of the mask, adjust your straps and reposition the nose piece until the mask has properly sealed against your face and you cannot feel air leaking out.

It’s important to note that N95 masks are not meant to be worn with beards or anything else that could cause a gap between the skin and the mask. Facial hair, facial piercings, or other obstructions can prevent the mask from properly sealing against the face. So, be sure that the area around your chin, mouth, and nose is free of any obstructions before applying an N95 mask.


Now that you have a better understanding of N95 masks, let’s examine the unique characteristics of KN95 masks:

KN95 Masks: Health Standards, Characteristics, and Usage


KN95 masks are, in theory, no different from N95 masks. However, they differ in their origin and safety requirements. While N95 masks are regulated by agencies in the United States, KN95 masks are regulated and produced by state-run agencies in China. Chinese agencies use different testing methods, though KN95 masks are generally thought to be equivalent to the N95 masks produced in the United States.


A recent study of KN95 masks shipped from China showed that there are significant differences in quality between the two types of masks. According to the report, between 60-70% of Chinese-made KN95 masks do not filter 95% of particles. This report was troubling for several reasons. First and foremost, the U.S. health workers who used KN95 masks were at greater risk of contracting and spreading COVID-19 than those workers who had access to N95 masks. Secondly, the current shortage of N95 masks means that more health workers will be forced to use KN95 masks, despite the potential risks. 

KN95 Mask Testing


In any case, KN95 masks do have to meet certain health standards. Here is the available data concerning KN95 testing, provided by 3M Science:


“Based on this comparison, it is reasonable to consider China KN95, AS/NZ P2, Korea 1st Class, and Japan DS2 FFRs as ‘similar’ to US NIOSH N95 and European FFP2 respirators, for filtering non-oil-based particles such as those resulting from wildfires, PM 2.5 air pollution, volcanic eruptions, or bioaerosols (e.g. viruses). However, prior to selecting a respirator, users should consult their local respiratory protection regulations and requirements or check with their local public health authorities for selection guidance.”


Certification/ Class (Standard)

N95 (NIOSH-42C FR84)

KN95 (GB2626-20 06)

Filter performance – (must be ≥ X% efficient)

≥ 95%

≥ 95%

Test agent

NaCl

NaCl

Flow rate

85 L/min

85 L/min

Total inward leakage (TIL)* – tested on human subjects each performing exercises

N/A

≤ 8% leakage (arithmetic mean)

Inhalation resistance – max pressure drop

≤ 343 Pa

≤ 350 Pa

Flow rate

85 L/min

85 L/min

Exhalation resistance - max pressure drop

≤ 245 Pa

≤ 250 Pa

Flow rate

85 L/min

85 L/min

Exhalation valve leakage requirement

Leak rate ≤ 30 mL/min

Depressurization to 0 Pa ≥ 20 sec

Force applied

-245 Pa

-1180 Pa

CO2 clearance requirement

N/A

≤ 1%


Additionally, 3M Science offers the following definitions to clarify the information in the table above:


Filter performance – The filter is evaluated to measure the reduction in concentrations of specific aerosols in the air that passes through the filter. 


Test agent - The aerosol that is generated during the filter performance test. 


Total inward leakage (TIL) – The amount of a specific aerosol that enters the tested respirator facepiece via both filter penetration and face seal leakage, while a wearer performs a series of exercises in a test chamber. 


Inward leakage (IL) – The amount of a specific aerosol that enters the tested respirator facepiece, while a wearer performs normal breathing for 3 minutes in a test chamber. The test aerosol size (count median diameter) is about 0.5 micrometer. 


Pressure drop – The resistance air is subjected to as it moves through a medium, such as a respirator filter.”

KN95 Mask Characteristics


Though functionally similar (in theory) to N95 masks, KN95 masks look slightly different than their American counterparts. More specifically, KN95 masks are more malleable than N95 masks. Additionally, KN95 masks have more of a cone-shape, while N95 masks typically have a rounded exterior. 


In many ways, KN95 masks resemble a stronger version of traditional surgical masks. They do not have the ability to add a valve, though they do have the capacity for a nose clip. One key difference between N95 masks and KN95 masks is the straps. As previously mentioned N95 mask straps usually go around the back of the head and the neck. Alternatively, KN95 mask straps go around each ear.

How to Use KN95 Masks


Generally speaking, you can use the same steps to apply a KN95 mask as you would for an N95 mask. However, there are a few important differences due to the straps:


  1. Hold the KN95 mask in your hands with the front of the mask (exterior) facing downwards. Your fingertips should be placed on the nosepiece.
  2. Place the respirator on your face with the straps hanging down. Position the mask so that it fully covers your nose and chin (be sure not to touch the interior of the mask with your hands).
  3. Hold the mask in place with one hand while using the other hand to wrap each strap around the corresponding ear. The straps should allow the mask to fit tightly against your face.
  4. Use your fingers to mold the metallic nosepiece (if applicable) so that it fits the shape of your nose.
  5. To test your KN95 mask, cup both hands over the mask and begin to inhale and exhale strongly. If you can feel air leaking around the edges of the mask, adjust your straps and reposition the nose piece until the mask has properly sealed against your face and you cannot feel air leaking out.

Where to Buy N95 Masks and KN95 Masks


You can shop online now on Clinical Supplies USA for 3M N95 masks, KN95 masks, and a host of FDA approved and medical grade PPE.