Researchers of Klaipėda University (KU) continue cooperation with business. When information appeared in the public space that some of the protective devices used during the pandemic may be unsafe, the Klaipėda FEZ applied to the university in early April for the respirator testing. Last week, the performance characteristics of Cloud Line Face Shield, a CE-certified plastic face shield made in Saulius Jokužis publishing house, one of the largest in Western Lithuania, were tested. Once their safety has been confirmed, the devices are successfully used by both the company’s employees and doctors.
Tested in four ways
At this time during the pandemic, KU researchers assisted Jokužis publishing house with their knowledge and skills. The performance characteristics of the face shields produced by the company have been tested.
The tests proved that those shields can be used not only as personal protective equipment. They are also good for doctors working with COVID-19 infected patients. Ozone gas has been found to be the least harmful method of disinfection for shield materials.
In compliance with UNE EN ISO 527-3: 2019, the researchers prepared samples from protective face shields. To identify their performance characteristics, the shields were disinfected: with UV radiation, in an ozone chamber, by one minute-exposure to isopropanol as well as one minute-exposure to commercial disinfectant containing 80% ethanol by mass. As explained by Artūras Tadžijevas and Žydrūnas Lukošius, researchers of the Marine Research Institute of KU, light transmission and UV absorption tests were performed to determine the degree of depreciation. The test for mechanical properties was also performed to identify the loss of plasticity by assessing it through a decrease in relative linear elongation values, modulus of elasticity, and tensile strength. The researchers also evaluated changes in the microstructure.
As proved by the tests, the shields were able to protect from secretion droplets spreading during patient coughing or sneezing, so that they do not get on the skin of the face or in the eyes. Consequently, the tested equipment can be successfully used in practice. “It is good that the cooperation between science and business allows us to use safe and reliable Lithuania-made devices in the fight against the pandemic”, concluded dr. Benediktas Petrauskas, KU Vice-Rector for Infrastructure and Development.
Named the safest way to disinfect
Tadžijevas and Lukošius, researchers of the Marine Research Institute of KU, pointed out that ozone gas was found to be the least harmful method of disinfection for the shield material. “Commercial glycerin/ ethanol solution is good for shield disinfection up to approximately 60 times. Isopropanol and UV can be used for disinfecting for about 30 times; afterwards visibility can be impaired due to micro-scratching resulting from disinfection and the yellowing of PET. It should be noted that, due to UV radiation, the PET of the shield becomes brittle. Due to the change in mechanical properties during disinfection with UV radiation, it is not recommended to exceed 100 minutes of the total exposure time”, Lukošius summarised the results of the testing. The tested face shields were also suitable for outdoor use.
“It is to be welcomed that in these troubled times, the combination of our available technologies and the abilities and knowledge of competent researchers has been used to test protective face shields. We respond to the situation in the country and want to supply only safe and tested protection devices. Therefore, we did not hesitate to contact KU experts for the testing of their performance properties. We thank you for the prompt response of the researchers and the insights provided, which will help us to produce even better protective face shields, ”said S. Jokužis, the head of the publishing house, and thanked the University community. The safe protection devices are already in use in healthcare institutions.