One of the earliest community designs, the Prusa was verified by the Czech Republic Ministry of Health and is now being produced in many countries. It is commonly made by community volunteers, but some large companies have also dedicated arrays of 3D printers to make them. The 3D printed headband is paired with a laser (or die) cut clear visor that comes in normal and extended sizes, and there is also a community version which uses a punched A4 plastic sheet for the visor.
Comfort: Wide headband and adjustable, elasticated strap comfortable to wear, some users have suggested the headband doesn’t conform well to those with very small or large heads. Weighs approximately 60g.
Ease of use: Elasticated strap easy for donning, and adjustable. Inherently resistant to fogging due to the ventilation from an open top.
Safety: Since the visor is quite far from the face (to give room for goggles and respirator), the narrow 240mm (normal) and 300mm (community version with A4 sheet oriented landscape) visors provide less than the minimum coverage width defined in British Standard EN168. There is no protection from droplets falling over the top of the visor, though a variant is available with added ‘brow guard’ protection, shown below. A Prusa variant with a top cover has been approved for use by the USA National Institutes of Health (NIH). Other features are as above. This is not widely made or part of any CE marking application that we are aware of.
UK approval: Variants of the design are at different stages of applying for CE marking. The University of Nottingham has a CE marked design and process but had to make changes to several elements including the clear visor coverage. 3DCrowd are seeking approval for distributed production of the EU RC3 design with the normal clear visor, using 3DCrowd’s standard operating procedures. It is anticipated that they will need to increase the visor size to obtain approval.
Sterilisation: Many of the processes tested by prusa and verified by Czech laboratories may be used, but our understanding is that sterilisation experts in hospitals remain skeptical, despite wiping down and visor reuse becoming common practice in the current circumstances. This reservation remains because partially porous 3D printed materials are notoriously difficult to reliably sterilise. It is acceptable for the visor itself to be cleaned with wipes.
Prusa RC3 (Image: https://www.prusa3d.com/covid19/)
Prusa brow guard (Image: https://www.prusaprinters.org/prints/27748-dtm-v30-a4-face-shield-ppe-for-covid-19-remix-of-p)