No.
Revision:
Effective:
Page:
EZKZ01
V2.0
2020-03-28
Page 14 of 28
SHANGHAI EARNTZ NONWOVEN.,LTD
Technical File of Earntz Protective Face Mask
Page 16 of 28
3.1.2 Design and Development inputs
Information for users
When breathing, speaking, coughing, sneezing etc., one releases smaller or larger
amounts of droplets of secretions from the mucous membranes in the mouth and nose.
Those droplets quickly evaporate and leave nuclei suspended in the air. The majority of
the nuclei are between 0.5 μm and 12 μm in diameter and especially the larger droplets
can contain micro-organisms from the source site. Nuclei can subsequently spread
through the air to a susceptible site such as an open operating wound or sterile
equipment.
The level of efficiency offered by a mask depends on a number of factors such as the
filtration efficiency, quality of the material and the fit of the mask on the wearer’s face.
Different designs are suited for different applications and the careful choice of mask is
therefore important in order to achieve the desired result.
The filtration capacity of mask materials can vary depending on the filter media. The fit
of masks varies considerably from those which are held in place by ear loops fastened
behind the wearer’s ears to those with tie bands around the head and a nose clamp
that can be shaped to the wearer’s nose. The effect of a very good or less good fit can
be tested in vivo whereas the filtration efficiency may be reproducibly tested in vitro.
The considerable variations in results when masks are tested in vivo results in the need
for large groups of test subjects and observations. It is thus usual to characterise mask
performance using in vitro tests of the material from which the mask is made. It is,
however, important to consider the fit of the mask carefully when a mask for a certain
application is chosen. Users should request such information from their suppliers.
A further factor to be considered is the capacity of the mask to absorb moisture from
the exhaled air and thereby to maintain its performance over a longer period of time.
The more advanced designs easily maintain their performance throughout even very
long operations whereas the less advanced ones are intended only for short
procedures.
The contamination risk resulting from hand contact with a used mask means that it is
essential that the mask is taken off and disposed of when no longer worn over nose and
mouth. When there is a further need for protection then a new mask should be put on.
Touching a used face mask or putting on a new one should always be followed by a full
hand disinfection procedure and a used mask should always be disposed of when no
longer needed or between two procedures.
In summary, to use an appropriate mask is an effective means to protect the working
environment from droplet contamination from nose and throat during health care
procedures. Masks with very different performance are, however, available. Therefore
