Difference of FFP2, KN95, and N95 and Other Filtering Facepiece Respirator Classes

DescriptionFiltering facepiece respirators (FFR), which are sometimes called disposable respirators, are subject to various regulatorystandards around the world. These standards specify certain required physical properties and performance characteristics inorder for respirators to claim compliance with the particular standard. During pandemic or emergency situations, healthauthorities often reference these standards when making respirator recommendations, stating, for example, that certainpopulations should use an “N95, FFP2, or equivalent” respirator.This document is only intended to help clarify some key similarities between such references, specifically to the following FFRperformance standards:

• N95 (United States NIOSH-42CFR84)

• FFP2 (Europe EN 149-2001)

• KN95 (China GB2626-2006)

• P2 (Australia/New Zealand AS/NZA 1716:2012)

• Korea 1st class (Korea KMOEL - 2017-64)

• DS (Japan JMHLW-Notification 214, 2018)

As shown in the following summary table, respirators certified as meeting these standards can be expected to function verysimilarly to one another, based on the performance requirements stated in the standards and confirmed during conformitytesting.

One notable comparison point is the flow rates specified by these standards for the inhalation and exhalation resistancetests. Inhalation resistance testing flow rates range from 40 to 160L/min. Exhalation resistance testing flow rates range from30 to 95 L/min. Some countries require testing to be performed at multiple flow rates, others at only the high or low end ofthose ranges. Although this appears to suggest that the standards’ requirements for breathing resistance (also called “pressuredrop”) differ from each other, it’s important to understand that pressure drop across any filter will naturally be higher athigher flow rates and lower at lower flow rates. Given typical pressure curves for respirator filters, the standards’ variouspressure drop requirements are actually quite similar. This chart shows a representative filter pressure drop curve. If onefilter is tested at a high flow rate, the pressure drop performance will be relatively high. If that same filter is tested at a lowflow rate, the pressure drop performance will be relatively low.

Based on this comparison, it is reasonable to consider China KN95, AS/NZ P2, Korea 1st Class, and Japan DS FFRs as“equivalent” to US NIOSH N95 and European FFP2 respirators, for filtering non-oil-based particles such as those resultingfrom 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 healthauthorities for selection guidance.

DefinitionsFilter performance – the filter is evaluated to measure the reduction in concentrations of specific aerosols in air that passesthrough 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 filterpenetration and faceseal 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 anormal breathing for 3 minutes in a test chamber. The test aerosol size (count median diameter) is about 0.5 micro meter.Pressure drop – the resistance air is subjected to as it moves through a medium, such as a respirator filter.