For our comfort study we are looking for 50 volunteers. Bring your mask and we will:
- Test your mask on filter efficiency and breathing resistance.
- Ask you various questions concerning the comfort of the mask you use.
- Maximum time needed is 20 minutes
- REWARD: Tony's chocolonely chocolate bar
REGISTER HERE for a specific timeslot in week 49 (30 November - 4 December). A TU/e e-mail account is necessary to register.
Alternatively email Kevin Vos: k.g.m.vos@student.tue.nlWe hope to see you then!
Measurements take place in the Darcy Lab which is located in Gemini (close to cantine)
_______________________________________________________
Introduction Aerosol filtering test Breathing Resistance test Results Comfort study Technical details
INTRODUCTION
Our goals:
- Cheap open source hardware/ software test for consumer face masks
- Comfort study of the use of consumer face masks
See also youtube (in Dutch): Coronacrisis inspireert Eindhovense mode-ontwerpers
With the Covid pandemic there is clear need for testing of face masks for consumers. However the standard certified tests for medical/surgical masks are expensive. This is partly due to the fact that they are also testing for resistance to blood droplets etc. As a result there is need for a simple test which can give a first order indication on the efficiency of consumer masks. Here we set out to develop a simple test which uses low-cost standard components and can be reproduces by anybody, i.e., open source hardware/sofware. For example we have used a standard particulate matter sensor (commercial price 40 Euro), which can detect aerosol droplets from 0.3 µm onward, which is in the range of a virus. Based on these low cost elements, two setups have been developed, i.e., an aerosol filtering and a breathing resistance test. Hence based on these tests one can get a first order impression of the efficiency of a particular consumer face mask. However there is a third axis, i.e., the comfort for wearing of a face mask. A good functioning face mask with no-comfort will not be used by consumers.
AEROSOL FILTERING TEST
In this test we determine the efficiency for aerosol filtering of a face mask. Using a standard consumer nebuliser an aerosol stream of a 1% NaCl solution is generated (A nebuliser is normally used for changing a medication from a liquid to a mist, so that it can be more easily inhaled into the lungs). Using a fan this aerosol stream is sucked through the face mask. Using a standard particulate matter sensor we measure the particle distribution which passes through the face mask. The measurement principle of this industrial sensor is based on laser scattering. By measuring the particle penetration before and after, we can get a relative measurement of the efficiency of a face mask.
A picture of the set up for measuring the aerosol filtering efficiency. Here use is made of a consumer nebuliser for generating an aerosol stream, whereas an industrial particulate matter sensor is used for determining the particle penetration.
BREATHING RESISTANCE
In this test we determine the breathing resistance of a mask by measuring the pressure difference of a face mask as generated during a flow. In order to generate the flow we make use of a standard low-cost pressure generator. Using a low-cost differential pressure sensor we measure the pressure difference. In order to compare the various masks we compare the resistance to a standard medical face mask.
A picture of the set up for measuring the breathing resistance. Here us is made of a consumer compressor to generator to generate an airflow. Using a differential pressure sensor the pressure drop is measured of the face mask, which is a measure for the breathing resistance.
Technical specifications / building instructions
RESULTS
Based on these 2 measurement we can plot the scaled aerosol penetration and the scaled breathing resistance for various face masks. We can distinguish roughly 4 categories:
A figure showing the results for various face masks
COMFORT STUDY
Both the aerosol filtering test and the breathing resistance test are tests which look at material parameters, i.e., they only test the materials of which is a face mask is made. However there is an important third axis, i.e., comfort for wearing. Ideally a face mask has a high efficiency for aerosol filtering and a low breathing resistance and is also easy to wear. However as many have us have experienced, there is a large difference in comfort of face masks, e.g., putting in on an off if you wear glasses. In our comfort study we want to see if there is any correlation between the aerosol filtering test, the breathing resistance test and comfort for wearing as experienced by a user
13-11-2020
The information contained in this website is for personal use only. While we endeavour to keep the information up to date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to the website or the information, products, services, or related graphics contained on the website for any purpose. Any reliance you place on such information is therefore strictly at your own risk. In no event will we be liable for any loss or damage including without limitation, indirect or consequential loss or damage, or any loss or damage whatsoever arising from loss of data or profits arising out of, or in connection with, the use of this website. Through this website you are able to link to other websites which are not under the our control and we have no control over the nature, content and availability of those sites and have no control over pop-us.
