This post was last updated on January 13th, 2021 at 11:33 pm
The DynaPro KN95 Respirator is a five laminate design, with dual non woven and melt blown layers as well as a single hot air cotton layer. The first (outer) layer is made from non woven fabric and the next two layers are made from melt blown fabric. The fourth and fifth layers are made from hot air cotton and non woven material respectively. The DynaPro KN95 measures 22cm x 16.5 cm.
DynaPro KN95 Respirator – Tested Performance Levels
The DynaPro KN95 is built to meet the GB2626-2006 executive standard. As with the NIOSH standard that governs the Almedic N95 and other N95 respirators, GB2626-2006 requires a filtration rate of 95% or more in relation to non oil 3 micron sized particles. Testing results for the DynaPro KN95 display filtration rates ranging between 99.6% and 99.8% for the 15 samples tested.
GB2626-2006 also requires inhalation and exhalation resistance levels of not more than 350 and 250 Pa respectively under an 85 L/min flow rate. These resistance levels indicate the ease with which the wearer of the respirator can breathe while wearing it. Testing results for the DynaPro KN95 Respirator show resistance levels under 150 Pa and 120 Pa respectively. These indicate that the DynaPro KN95 presents minimal breathing interference despite providing the high levels of filtration reported above.
Total Inward Leakage
The Total Inward Leakage (TIL) levels of the DynaPro KN95 are also well within GB2626-2006 standards. Total Inward Leakage refers to the total amount of contaminated air leaking through different parts of the respirator. These parts include the face seal. valves and gaskets (where present) and the filter itself. The GB2626-2006 standard requires that, out of 50 “types of action”, the TIL of at least 46 should be under 11%. In addition, out of 10 tested samples, the TIL of at least 8 should be less than 8%.
Testers performed 50 types of action on 10 DynaPro KN95 Respirator samples. All resulted in TIL levels below 11%, with the highest recorded TIL being 6.0%. For the 10 samples tested, all recorded TIL levels were under 8%, with the highest recorded level at 5.6%
Among other things, TIL is a function of the effectiveness of the seal between the facial contours of the wearer and the edges of the respirator. It is important to note that respirators that conform to the NIOSH standard do not have to demonstrate any stated TIL levels.
DynaPro KN95 Respirator Design – Head Strap Harnessing
The DynaPro KN95 respirator uses a head strap harness.
This is in contrast to the earloop harness common among other KN95 respirators. In general, head straps result in a more effective seal than the earloop design. A recent NIOSH study has unearthed evidence indicating greater difficulty achieving a close fit when using an earloop harness.
Athough a respirator needs to have a high filtration rate to be effective, it is equally important that the seal around the contours of the face should be airtight to eliminate the risk of inward leakage of the 3-5 micron sized particles against which it needs to be effective. A respirator that has a high filtration rate but that leaks around the face is not that more effective than one with a poor filtration rate. This is one of the design features that the TIL metric mentioned above takes into account.
In addition to the head strap design’s superior facial fit, it also results in a more comfortable wearing experience. The pressure of earloops against the backs of the ears can become uncomfortable over extended wearing periods.
To further improve the closeness of its fit to the face, the DynaPro KN95 uses adjustable metallic nasal splints. These help to assure a contoured and secure fit to a wide variety of facial shapes.