Face shield

{{short description|Device used to protect the wearer's face from hazards}}

File:US Navy 110301-N-DR144-037 Electrician's Mate Fireman Alex Kline, assigned to the electrical division of the engineering department of the Nimitz-c.jpg Electrician's Mate wearing a face shield while checking for bad fuses on a lighting panel]]

File:Mask Nurse Donna Wood in her safety suit.jpg, 2014.]]

A face shield, an item of personal protective equipment, aims to protect the wearer's entire face (or part of it) from hazards such as flying objects and road debris, chemical splashes (in laboratories or in industry), or potentially infectious materials (in medical and laboratory environments).{{Cite web |title=What is Face Shield? - Definition from Safeopedia |url=http://www.safeopedia.com/definition/9058/face-shield |access-date=2022-03-28 |website=safeopedia.com}}

Applications

= Medical =

File:Covid-19 Brazil - Amazon Health 002.jpg]]

File:Efficacy of Face Shields Against Cough Aerosol Droplets from a Cough Simulator.webm

In medical applications the device is used to protect a medical professional during a procedure that might expose them to blood or other potentially infectious fluids or aerosols. An example is the use of a CPR mask while performing rescue breathing or CPR. Another example is the use of face shields to reduce the likelihood of inhaling potentially infectious bioaerosols.{{Cite journal |last1=Varela |first1=Andrea Ramirez |last2=Gurruchaga |first2=Alejandro Pacheco |last3=Restrepo |first3=Silvia Restrepo |last4=Martin |first4=Juan David |last5=Landazabal |first5=Yessica Daniela Campaz |last6=Tamayo-Cabeza |first6=Guillermo |last7=Contreras-Arrieta |first7=Sandra |last8=Caballero-Díaz |first8=Yuldor |last9=Florez |first9=Luis Jorge Hernandez |last10=González |first10=John Mario |last11=Santos-Barbosa |first11=Juan Carlos |last12=Pinzón |first12=José David |last13=Yepes-Nuñez |first13=Juan José |last14=Laajaj |first14=Rachid |last15=Buitrago Gutierrez |first15=Giancarlo |date=2022-08-20 |title=Effectiveness and adherence to closed face shields in the prevention of COVID-19 transmission: a non-inferiority randomized controlled trial in a middle-income setting (COVPROSHIELD) |journal=Trials |volume=23 |issue=1 |pages=698 |doi=10.1186/s13063-022-06606-0 |doi-access=free |issn=1745-6215 |pmc=9391623 |pmid=35987694}}

{{see also|Shortages related to the COVID-19 pandemic#Medical face shield}}

= Police and military =

File:AssaultTraining2016-18.jpg|Russian combat engineer with a 6B47 helmet and ballistic face shield|alt=

File:US Navy 060127-N-9641C-002 Chief Damage Controlman, John Brooks, removes the face shield from a Sailor's MCU-2-P gas mask.jpg|alt=text|Removing a face shield from a Sailor's MCU-2/P gas mask after washing it with decontamination solution during a General Quarters Drill aboard an aircraft carrier

In military or law 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,A. Hunsicker: Behind the Shield: Anti-Riot Operations Guide Universal Publishers, 2011, {{ISBN|978-1612330358}}, p. 166 but is usually designed to withstand low velocity impacts, like caused by punches or thrown objects.[https://www.polizeipraxis.de/startseite/news-detailansicht/artikel/die-helm-maskenkombination-hmk.html article: "Die Helm-Maskenkombination HMK"] {{Webarchive|url=https://web.archive.org/web/20190508111837/https://www.polizeipraxis.de/startseite/news-detailansicht/artikel/die-helm-maskenkombination-hmk.html |date=2019-05-08 }} on polizeipraxis.de (german)

A ballistic face shield is designed to stop or deflect blast and fragments from operators wearing bomb suitsAshok Bhatnagar: Lightweight Ballistic Composites: Military and Law-Enforcement Applications, Woodhead Publishing, 2018, {{ISBN|978-0081004067}}, pp. 133, 222 To protect the wearers eyes and face from ballistic threats in combat is envisioned in the PEO Soldier program for the United States Department of Defence.Ashok Bhatnagar: Lightweight Ballistic Composites: Military and Law-Enforcement Applications, Woodhead Publishing, 2018, {{ISBN|978-0081004067}}, pp. 396, 397

= Construction =

A face shield is intended to protect the wearer's partial or entire face and the eyes from hazards. Face shields should be used with spectacles and/or goggles.ANSI Z87.1-2003, page 11 On many construction sites many workers 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 include welding equipment or metal chop saws.

Manufacturing

Two methods are used to manufacture face shields: extrusion and injection molding. Face shields cut from extrusion sheets provide better impact resistance than injection-molded face shields because extrusion sheets are made of high molecular weight plastic pellets while injection molding must use lower molecular weight plastic pellets, which provide better melt flowing property needed by injection molding.

Face shields can be made of polycarbonate which provides excellent impact resistance, optical quality, heat resistance and normal chemical resistance. Or cellulose acetate which provides normal impact resistance, optical quality, heat resistance and good chemical resistance.

Face shields {{convert|0.8|mm|abbr=on}} thick made of extrusion polycarbonate sheets can withstand the impact of a {{convert|6|mm|abbr=on}} nominal diameter steel ball traveling at the speed {{convert|120|m/s|abbr=on}} (European standard, protection against high-speed particles – medium energy impact), while injection molding face shields must have at least {{convert|1.5|mm|abbr=on}} thickness to withstand the same impact. But injection molding can provide more complicated shape than extrusion.

During the COVID-19 pandemic, people from 86 countries engaged in the voluntary production of PPE to supplement traditional supply chains - many of which had been interrupted.{{Cite web|title=DESIGN {{!}} MAKE {{!}} PROTECT|url=https://opensourcemedicalsupplies.org/impact/|access-date=2021-02-22|website=Open Source Medical Supplies}} They collectively produced a total of 25 million face shields with techniques including 3D printing & Laser cutting, in addition to injection molding.

File:3D printing of face shields.jpg|3D printing of face shields during COVID-19 pandemic

File:Headpiece.stl|3D file for printing a face shield{{cite web |title=GliaX/faceshield |url=https://github.com/gliax/faceshield |publisher=Glia Free Medical hardware |access-date=23 March 2020 |date=23 March 2020}}

File:Buckle.stl|Buckle for the face shield

File:FaceShield3D20.jpg|Final shield

Standards

;ANSI (American Standard)

Mark Z87: Basic impact: Faceshields shall be capable of resisting impact from a 25.4 mm (1 in) diameter steel ball dropped from a height of 127 cm (50 in).
Mark Z87+: High impact: Faceshields shall be capable of resisting impact from a 6.35 mm (0.25 in) diameter steel ball traveling at a velocity of 91.4 m/s (300 ft/s).

;EN 166 (European Standard)

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.

Mark A: {{convert|190|m/s|abbr=on}}
Mark B: {{convert|120|m/s|abbr=on}}.
Mark F: {{convert|45|m/s|abbr=on}}.
ref. EN166

;CSA (Canadian Standard)

Z94.3-15 Eye and Face Protectors Class 6 relates to face shields, and is divided into 3 sub-classes

6A – Impact, piercing, splash, head, and glare protection.
6B – Radiation protection. Also for low heat, splash, glare, and light non-piercing impact protection.
6C – High-heat applications and light non-piercing impact protection only.
ref. CSA Z94.3-15