Welding arc rays from all the welding processes produce intense, visible and invisible (ultraviolet and infrared) rays that can burn eyes and skin.
Wear an approved welding helmet fitted with an appropriate shade of filter lens to protect your face and eyes when welding or watching.
Wear approved safety glasses with side shields under your helmet.
Never use broken or faulty welding helmets.
Always ensure there are adequate protective screens or barriers to protect others from flash, glare and sparks from the welding area.
Ensure that there are adequate warnings that welding or cutting is taking place
See the chart below that gives you an appropriate filter lens shade number based on the amps being used and the welding or cutting process.