Aface shield, an item ofpersonal protective equipment, aims to protect the wearer's entireface (or part of it) fromhazards such asflying objects androad debris, chemical splashes (inlaboratories or inindustry), or potentiallyinfectious materials (inmedical and laboratory environments).[1]
Inmedical applications the device is used to protect a medical professional during a procedure that might expose them toblood or other potentially infectious fluids or aerosols. An example is the use of aCPR mask while performingrescue breathing orCPR. Another example is the use of face shields to reduce the likelihood of inhaling potentially infectious bioaerosols.[2]
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Inmilitary orlaw enforcement environments, a face shield may be designed for ballistic or non-ballistic protection. The non-ballistic shield will provide no protection from projectiles shot from firearms,[3] but is usually designed to withstand low velocity impacts, like caused by punches or thrown objects.[4]
A ballistic face shield is designed to stop or deflect blast and fragments from operators wearingbomb suits[5] To protect the wearers eyes and face from ballistic threats in combat is envisioned in thePEO Soldier program for the United States Department of Defence.[6]
A face shield is intended to protect the wearer's partial or entire face and the eyes from hazards. Face shields should be used withspectacles and/orgoggles.[7] On manyconstruction sites manyworkers use face shields to protect them from debris or sparks. Many tools for cutting and working with metal recommend the use of a face shield. Examples includewelding equipment ormetal chop saws.
Two methods are used to manufacture face shields:extrusion andinjection molding. Face shields cut from extrusion sheets provide betterimpact resistance than injection-molded face shields because extrusion sheets are made of highmolecular weightplastic pellets while injection molding must use lower molecular weight plastic pellets, which provide bettermelt flowing property needed by injection molding.
Face shields can be made ofpolycarbonate which provides excellentimpact resistance, optical quality,heat resistance and normalchemical resistance. Orcellulose acetate which provides normal impact resistance, optical quality, heat resistance and good chemical resistance.
Face shields 0.8 mm (0.031 in) thick made of extrusionpolycarbonate sheets can withstand the impact of a 6 mm (0.24 in) nominal diameter steel ball traveling at the speed 120 m/s (390 ft/s) (European standard, protection against high-speed particles – medium energy impact), while injection molding face shields must have at least 1.5 mm (0.059 in) thickness to withstand the same impact. But injection molding can provide more complicated shape than extrusion.
During theCOVID-19 pandemic, people from 86 countries engaged in the voluntary production of PPE to supplement traditional supply chains - many of which had been interrupted.[8] They collectively produced a total of 25 million face shields with techniques including3D printing &Laser cutting, in addition to injection molding.
![3D file for printing a face shield[9]](/image.pl?url=http%3a%2f%2fen.wikipedia.org%2f%2fupload.wikimedia.org%2fwikipedia%2fcommons%2fthumb%2fb%2fbe%2fHeadpiece.stl%2f250px-Headpiece.stl.png&f=jpg&w=240)
These shields are for protection against high-speed particles, and must withstand the impact of a 6 mm nominal diameter steel ball, striking the oculars and the lateral protection at the speed stated.
Z94.3-15Eye and Face Protectors Class 6 relates to face shields, and is divided into 3 sub-classes
Media related toFace shields at Wikimedia Commons