The KN95 designation represents a performance standard for a filtering facepiece respirator (FFR) designed to filter airborne particles. It is the official standard used within China, established by the country’s regulatory body. The respirator is certified to achieve 95% filtration efficiency against non-oil-based solid and liquid aerosols. The KN95 standard ensures that products bearing this mark meet specific manufacturing and testing requirements for respiratory protection.
The Meaning of the KN Standard
The name KN95 is an acronym embedded in the Chinese national standard, GB 2626-2019, which defines requirements for non-powered air-purifying particle respirators. The “K” in KN stands for Kuai, denoting a particulate filtering respirator classification. This signifies the mask’s function is to protect the wearer from fine particulate matter.
The “N” specifies the filter is Non-oil resistant. This classification means the mask is certified to filter solid particles and water-based liquid aerosols, such as those carrying viruses or pollution, but not oil-based aerosols. Other classifications, such as “KP,” exist for filters resistant to both oil and non-oil particulates.
The numerical designation “95” represents the minimum filtration efficiency required for the filter material. A KN95 respirator must block at least 95% of airborne particles that are 0.3 micrometers in diameter or larger under strict testing conditions. This high threshold makes the KN95 an effective form of personal respiratory protection.
Key Requirements for Certification
For a respirator to bear the KN95 designation, it must pass several performance tests outlined in the GB 2626-2019 standard. The primary hurdle is the filter efficiency test, which confirms the 95% particle filtration rate using sodium chloride aerosols. Manufacturers must also demonstrate acceptable breathability.
Breathability is measured through inhalation and exhalation resistance, often called pressure drop. The standard specifies maximum resistance levels for air drawn in and air pushed out through the filter material. For example, inhalation resistance must be below 350 Pascals (Pa) when tested at a flow rate of 85 liters per minute.
The total inward leakage (TIL) test assesses how much unfiltered air bypasses the filter material and enters the mask. This test accounts for filter penetration and leakage around the face seal while the wearer performs specific exercises. The GB standard requires that the total inward leakage must be 8% or less on average. Mandatory tests also include evaluating the strength of the head harness or ear loops and subjecting the material to flammability testing.
Distinguishing KN95 from N95
Although the KN95 and N95 share the 95% filtration efficiency rating, they are certified under different regulatory bodies and standards. The KN95 is governed by the Chinese standard GB 2626, while the N95 is regulated by the U.S. National Institute for Occupational Safety and Health (NIOSH) under the 42 CFR 84 standard. Regulatory oversight differs: KN95 relies on manufacturer self-attestation with government oversight, while N95 requires direct NIOSH approval before sale.
A technical difference lies in the fit testing requirements during certification. The NIOSH N95 standard mandates a formal fit test during the approval stage to ensure a tight seal against the face, and N95 masks typically use headbands to achieve this seal. In contrast, the KN95 standard does not require a formal fit test during certification, relying instead on the manufacturer’s seal specifications. This means the N95 standard places a greater emphasis on the guaranteed seal.
The standards also vary slightly in their breathability and leakage test methodologies. While both test for inhalation and exhalation resistance (pressure drop), the specific flow rates used for testing can differ. The N95 standard requires a total inward leakage (TIL) test for half-mask respirators, and the KN95 standard requires TIL to be less than 8% on average during testing. Despite these technical variances in testing parameters, the two classes are often considered functionally similar for filtering non-oil-based particles.
Practical Use and Authentication
For consumers, verifying the legitimacy of a KN95 mask is paramount due to the prevalence of counterfeit products. Authentic KN95 respirators must have specific markings printed clearly on the mask itself or on the packaging. Look for the standard number “GB 2626-2019” (or the older “GB 2626-2006”) alongside the manufacturer’s name or logo.
Proper use is essential to maximize the mask’s protective function, starting with achieving a secure seal against the face. When donning the mask, the metal nose clip must be firmly molded around the bridge of the nose to prevent air from leaking out the top. A quick user seal check, where the wearer exhales sharply to feel for air leakage around the edges, should be performed every time the mask is put on.
KN95 masks are typically single-use respirators, but they can be reused sparingly in non-healthcare settings until they become visibly dirty, damaged, or difficult to breathe through. To safely reuse a mask, store it in a clean, breathable paper bag between uses to allow any potential viral particles to degrade naturally. Avoid washing the mask or storing it in a sealed plastic bag, as this can degrade the filtration material and decrease its effectiveness.