#SafetyFirst: AVT tests masks from all over Germany

  phD student examining the test head © AVT  

Since the beginning of the corona crisis, hospitals have required significantly more FFP2 masks. Some of these are sourced from new suppliers, with various seals and certificates. But do they all offer the same protection? When this question reached the CVT it was clear: we must help.  After all, masks are filters, and filtration processes are well known at the CVT and DWI, where the working group of Matthias Wessling is based. Within less than ten days, a team was formed, a concept was developed, and a mask test rig was built and put into operation.

The team around senior engineer Dr. John Linkhorst has a cumulative experience of more than 50 years in filter and membrane processes with individual expertise. For example, Michael Alders, Stefan Herrmann, and Denis Wypysek were responsible for assembling the test rig, Maik Tepper and Lukas Hirschwald developed an innovative concept for functional mask holders, and Jens Rubner developed a test cell to examine only the filter material. Felix Stockmeier, Anna Kalde, and Georg Linz also provided support in the design of the test stand and took care of the systematization of the mask tests and data evaluation. Support from industry was provided by the spin-offs FURTHRresearch and ZUMOLab as well as the Aachen-based measurement technology company TSI. The support of the partners from the region contributed significantly to the success of the project. TSI GmbH provided an aerosol generator and detector for the test rig, ZUMOLab enabled data acquisition by providing control software and a measuring box, and FURTHRresearch accompanied the tests with know-how and its data management software.

The measuring procedure is based on the corresponding DIN standards and tests the masks as a whole including fashioning. AVT tests in three stages: First, the fit of the mask on a doll's head has to be assessed. A good fit ensures that no viruses can get past the mask and into the respiratory tract. Then measurements in a mask holder show the filtration performance. Finally, the properties of the actual filter material are checked to identify sources of error.

The measurements are in great demand. Within hours, the recorded measurement data is evaluated, processed, and forwarded to the appropriate facilities. In addition to the University Hospital Aachen, the CVT is in contact with hospitals throughout Germany, but also with other companies and institutions. Transparent and understandable communication? No problem, because thanks to the many and varied projects ranging from basic research in the field of filter materials, 3D printing, the construction of prototypes and pilot plants to the development of medical products, the staff of the CVT and DWI are used to interdisciplinary work.

In the meantime, well over 750 tests have been carried out, mostly with positive results. The demand for tests is high and so tests are continued daily. Many helping hands were and are necessary for this - naturally coordinated with each other according to a strict hygiene concept.

Ppress release of the RWTH