A KN95 mask is a half face, air purifying facepiece respirator that protects the wearer from harmful non oil particulate (not gaseous) matter. These devices are subject to Chinese GB2626-2006 standards for these respirators. These standards are broadly equivalent to the N95 standards. N95 standards are set out by the NIOSH in the US for equivalent facepiece respirators.
In general, the GB2626-2006 standards require the following performance levels from KN95 masks:
They must demonstrate a 95% filtration rate for salt sized particles flowing at a rate of 85 L/min;
The standards require them to protect the ability of the wearer to breathe adequately. Specifically, they are subject to maximum inhalation and exhalation resistance standards of 350 Pa and 250 Pa respectively;
KN95 masks should demonstrate adherence to maximum levels of leakage of contaminated air between the edges of the respirator and the wearer’s face. These are known as Total Inward leakage (TIL) standards.
The GB2626-2006 standards also require KN95 masks to be tight fitting to the face and free from deformation. The TIL standards represent the specification of the “tight fitting” standards.
There are also performance standards as far as exhalation valve leakage levels are concerned. However, the KN95 respirator masks in this section do not have exhalation valves, so those standards do not apply here.
Each KN95 mask that meets the GB2626-2006 standards should carry a label with the number and year of publication of the applicable standard e.g. “GB2626-2006”. The label should also show the type and grade of filter elements e.g. “KN95”.