Face shield

A face shield is a device used to protect wearer's entire face (or part of it) from impact hazard such as flying objects and road debris, 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 (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

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.
 * EN 166 (European Standard)
 * Mark A: 190 m/s.
 * Mark B: 120 m/s.
 * Mark F: 45 m/s.
 * ref. EN166

See also welding helmet.

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

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

Manufacturing
There are two methods to manufacture faceshields, extrusion and injection molding. 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 (European 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. 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.

Police
In riot protection, "face shield" often means a transparent visor.