In order to simulate the effectiveness of multiple wearing of common FFP2 masks, a special ventilation simulator was developed. Humidity, temperature, pressure and breathing time volume of human respiration during light physical exertion were thus precisely reproduced.
Tested for a total of 22 hours
Each mask was first “ventilated” for twelve hours with the ventilation simulator and then placed in a drying oven at 80 degrees Celsius for 60 minutes. The heat treatment in the oven at 80 degrees Celsius was examined and recommended by the Münster University of Applied Sciences as a hygiene measure when reusing FFP2 masks.
The mask was then connected to the ventilation simulator again for ten hours and then subjected to a second heat treatment in the drying oven. The masks were tested for filter performance and breathing resistance in cooperation with ift Rosenheim GmbH, an internationally accredited and notified test laboratory for FFP2 masks.
Don’t put it in your pocket
Twelve of the 15 FFP2 mask models examined passed the laboratory test. A mask model could not meet the standard regarding filter performance either in its brand new condition or after the usage simulation. “Such masks should not even come on the market,” criticized Schwarzbauer.
As a result of the usage simulation, the masks were exposed to a load for a total of 22 hours that would result from breathing during light physical activity. “If an FFP2 mask is only worn for a few hours a day with moderate physical activity, then I don’t see any problem in terms of protection and breathing comfort if this mask is reused for several days,” says Schwarzbauer. “For hygienic reasons, you shouldn’t just put the mask in your pocket after wearing it, but hang it up to dry.”
Easier breathing
Reusing the masks will reduce the breathing resistance of the masks. “This means that the masks offer a little more breathing comfort, but otherwise this is not a problem, as the protective effect is still given,” says Schwarzbauer.
A mask model, both in its brand new condition and after the use simulation, was above the maximum permissible limit value for breathing resistance. “Although this model offers sufficient protection against infection, the increased breathing resistance when inhaling can be problematic in the case of intense physical exertion or for older people,” explains Schwarzbauer. In another model, the limit value for breathing resistance was exceeded after the use simulation.
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