Face shields protect the whole face from impact, spatter and chemical splash. They are not a substitute for a welding helmet — the shade rating is what protects against arc radiation — but they cover the gaps a helmet leaves and are the right protection for grinding, cutting and chemical work.
Visor material determines the protection. Polycarbonate visors resist impact and are the standard for grinding and cutting. Acetate visors have better optical clarity but lower impact resistance, used for chemical splash and light work. Mesh visors allow airflow and are used for brush cutting and hot work where impact is the main hazard.
Headgear style affects comfort and compatibility. Ratchet headgear adjusts for fit; browguard styles are lighter. A face shield that can be worn over safety glasses is the practical setup — the shield protects the face, the glasses protect the eyes when the shield is raised.
Shade rating applies to some face shields used for light cutting and brazing. These are not welding helmets and should not be used for arc welding.
