Welding safety covers the protective equipment, workspace setup, and operating procedures necessary to prevent injury from arc radiation, heat, fumes, and fire. Welding produces intense ultraviolet and infrared radiation, molten metal spatter, and toxic fumes that require comprehensive protection. The welding arc emits UV radiation that can cause arc eye, a painful corneal burn similar to sunburn, within seconds of exposure without proper eye protection. [[Welder Types]] provides the context for selecting the appropriate welding process before safety considerations are addressed.
Welding helmets with auto-darkening lenses are the standard for eye and face protection. The lens shade should be number 10 to 13 for arc welding, with darker shades used for higher amperage processes. Auto-darkening lenses switch from light to dark state in 1/10000 to 1/25000 of a second and allow the welder to position the electrode without lifting the helmet. Welding goggles with side shields are worn under the helmet for additional protection from peripheral radiation. Spectators within 10 meters (30 feet) should use shade number 5 to 8 filter lenses.
Welding sparks and spatter can travel up to 10 meters (30 feet) and ignite flammable materials. The work area should be cleared of combustibles within a 10-meter radius. A fire extinguisher rated for Class A, B, and C fires must be readily accessible. A fire watch is required for 30 minutes after welding stops in areas where fire risk is elevated. Welding should never be performed on containers that have held flammable materials without thorough cleaning and purging.
Welding fumes contain metal oxides, ozone, and nitrogen oxides that are hazardous to respiratory health. Mild steel welding produces iron oxide fumes. Stainless steel welding produces hexavalent chromium, a known carcinogen. Galvanized steel welding produces zinc oxide fumes that cause metal fume fever. Local exhaust ventilation, a respirator with particulate filters, or both are required for indoor welding. Outdoor welding in still air still produces fume concentrations above exposure limits in the welder's breathing zone.
Welding clothing consists of flame-resistant materials, typically leather or heavy cotton, with no synthetic fabrics that could melt onto the skin. A welding jacket or bib apron protects the torso. Welding gloves, gauntlet style with leather palms, protect the hands. Leather boots with high tops prevent sparks from entering the footwear. Ear plugs are worn when welding overhead or in confined spaces.