A face shield is a device used to protect wearer's entire face

Face

The face is a central sense organ complex, for those animals that have one, normally on the ventral surface of the head, and can, depending on the definition in the human case, include the hair, forehead, eyebrow, eyelashes, eyes, nose, ears, cheeks, mouth, lips, philtrum, temple, teeth, skin, and...

 (or part of it) from impact hazard

Hazard

A hazard is a situation that poses a level of threat to life, health, property, or environment. Most hazards are dormant or potential, with only a theoretical risk of harm; however, once a hazard becomes "active", it can create an emergency situation. A hazard does not exist when it is not...

 such as flying objects and road debris

Road debris

Road debris, a form of road hazard, is debris on or off a road. Road debris includes substances, materials, and objects that are foreign to the normal roadway environment...

, chemical splashes (in industry), or potentially infectious fluid (in medical).

Industry

Face shield, a protective device commonly intended to shield the wearer's face, or portions thereof, in addition to the eyes, from certain hazards, depending on faceshield type. Faceshields shall be used only in conjunction with spectacles and/or goggles.

Standard

ANSI

Ansi

Ansi is a village in Kaarma Parish, Saare County, on the island of Saaremaa, Estonia....

 (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).
  • ref. ANSI Z87.1

EN 166

EN 166

EN 166:2002 is an european standard. It concerns the vast area of eye protection.EN166:2002 replaced the Standard, BS EN166:1996...

 (European Standard)
These 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: 190 m/s.
• Mark B: 120 m/s.
• Mark F: 45 m/s.
  • ref. EN166

See also welding helmet

Welding helmet

Welding helmets are headgear used when performing certain types of welding to protect the eyes, face and neck from flash burn, ultraviolet light, sparks, infrared light, and heat. Most commonly used with arc welding processes such as shielded metal arc welding, gas tungsten arc welding, and gas...

.

Material

Polycarbonate

Polycarbonate

PolycarbonatePhysical PropertiesDensity 1.20–1.22 g/cm3Abbe number 34.0Refractive index 1.584–1.586FlammabilityV0-V2Limiting oxygen index25–27%Water absorption – Equilibrium0.16–0.35%Water absorption – over 24 hours0.1%...

 (PC)
Provide excellent impact resistance, optical quality, heat resistance and normal chemical resistance.

Cellulose acetate

Cellulose acetate

Cellulose acetate , first prepared in 1865, is the acetate ester of cellulose. Cellulose acetate is used as a film base in photography, as a component in some adhesives, and as a frame material for eyeglasses; it is also used as a synthetic fiber and in the manufacture of cigarette filters and...

 (CA)
Provide normal impact resistance, optical quality, heat resistance and good chemical resistance.

Manufacturing

There are two methods to manufacture faceshields, extrusion

Extrusion

Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed or drawn through a die of the desired cross-section...

 and injection molding

Injection molding

Injection molding is a manufacturing process for producing parts from both thermoplastic and thermosetting plastic materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the cavity...

. Faceshields cut from extrusion sheets provide better impact resistance than injection molding faceshields 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. For example, even 0.8 mm thickness faceshields made of extrusion polycarbonate sheets can withstand the impact of a 6 mm nominal diameter steel ball traveling at the speed 120 m/s (Europen standard, protection against high-speed particles – medium energy impact), while injection molding faceshields must have at least 1.5 mm thickness to withstand the same impact. However, injection molding can provide more complicated shape than extrusion.

Medical

In medical areas, "face shield" refers to a variety of devices used to protect a medical professional during a procedure that might expose the worker to blood or other potentially infectious fluid. An example is the use of a CPR mask while performing rescue breathing or CPR

Cardiopulmonary resuscitation

Cardiopulmonary resuscitation is an emergency procedure which is performed in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person in cardiac arrest. It is indicated in those who are unresponsive...

. Another example is the use of personal protective equipment to guard the face against splashing, spraying or splattering of blood or other potentially infectious materials.