Masks made from simple fabric offer limited protection, say experts

Ensuring the protection of people's health and lives, especially in respirators and personal protective equipment (PPE) for use by health care personnel, has been one of the essential premises since the Artefactos community began to design and manufacture adaptations with which to face Covid-19.

Hence, much of the efforts of this scientific team - made up of medical doctors and researchers in biomedicine, engineering and industrial design from the University of Alicante, among other institutions - have been directed at studying and finding the right materials and technologies to help safely in this emergency. The result is that not any 3D printing can be used, because it is human lives that are at risk.

Javier Esclapés, PhD in Engineering from the University of Alicante and coordinator of Artefactos, points out that they see with admiration the large number of initiatives by people who are manufacturing respirators and protective equipment all over the world and that it is their responsibility to highlight the risks of this type of manufacturing.

As a result of their research, tests and experience, they can help ensure that human and material resources (filaments, fabrics and fabrics) are used in the best way possible, offering real protection against COVID-19.

Research reveals that the size of the SARS-CoV-2 virus is much smaller than 1 micron and can even pass through the protection of homemade masks created with 3-D printers. For this reason, healthcare practitioners need greater protection than surgical masks, and they warn of the limited protection offered by masks made from simple fabric or other non-approved materials.

Therefore, when manufacturing healthcare material in 3D printing, Artefactos stays that it is important to know the high porosity of the plastics used, which varies depending on the configurations and machines used.

In addition, printed parts often have irregular surfaces, fractures and pores through which viruses and bacteria can filter, hence the few materials approved by the Health Service for medical use. The use of flexible filaments to ensure that parts fit properly to the face is essential, yet not always possible.

Among their recommendations, the experts in this project at the UA warn that in order to manufacture respirators or masks guaranteed for medical use, not just any 3D printer is valid, and that the supervision of engineers is essential.

Both the WHO and the Ministry of Health recommend using FFP2 or FFP3 filters for isolations or exposure to infectious aerosols. These filters are made of duly tested "non-woven fabric" polypropylene, in compliance with European regulations.

However, in view of the shortage of these filters, the fastest alternative today is HEPA filters, which can remove up to 99.97% of particles larger than 0.3 microns and are already available in several Spanish hospitals.

Dive mask safety testing

On the Artefactos website, two of their design models to fight the virus are published openly, (and after finishing the tests, more models will be published depending on the available filters).

One of them, Skuba, proposes an adaptation to the Decathlon diving mask, so that they may be printed from anywhere in the world, with high-performance 3D printers, as the health safety of the product must be prioritised. In addition, more adaptations will be made for diving masks of other brands.

At the moment, the clinical efficacy of the adaptation is being tested so that, once the required safety tests have been passed, they can begin to be manufactured by injected plastic industries, which have offered their help to contribute to this project. At the same time, a list of healthcare personnel who might need this protection is being created, which could later be distributed by volunteers from the University of Alicante.

Institutional solidarity chain

What is also important is to stress that the chain of institutional solidarity generated by this health emergency, has given a quick response to such an extreme situation, especially in the confined conditions in which we have to work.

At present, AIJU is manufacturing 3,000 adapters designed by Artefactos with safe materials with a view to adapt the nearly 3,000 diving masks donated by the City of Ibi, which will be distributed by the hospitals in the province.

HEPA filters partially solve the problem of the shortage of health safety filters, while ATEVAL and textile companies are working on the development of new materials, which can be approved by AITEX.

Artefactos has dedicated a space on its website to inform about all these advances as well as to offer its knowledge about safety in manufacturing these devices so that individuals and groups of manufacturers who are developing PPE on their own can do so with the required health safety guarantees.