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Filter Lenses for Protection Against Radiant Energy

ERSONAL PROTECTION EQUIPMENT

Operations Electrode Size 1/32 in. Arc Current Minimum* Protective Shade
Shielded metal are welding Less than 3 Less than 60 7
3-5 60-160 8
5-8 160-250 10
More than 8 250-550 11
Gas metal are welding and flux cored arc welding   Less than 60 7
  60-160 10
  160-250 10
  250-500 10
Gas Tungsten arc welding   Less than 50 8
  50-150 8
  150-500 10
Air carbon (light) Less than 500 10
Arc cutting (heavy) 500-1000 11
Plasma are welding   Less than 20 6
  20-100 8
  100-400 10
  400-800 11
Plasma arc cutting (light)** Less than 300 8
(medium)** 300-400 9
(heavy)** 400-800 10
Torch brazing     3
Torch Soldering     2
Carbon arc welding     14

Filter Lenses for Protection Against Radiant Energy

Operations Plate thickness- in. Plate thickness- mm Minimum* Protective Shade
Gas Welding:
Light
Under 1/8 Under 3.2 4
Medium
1/8 to 1/2 3.2 to 12.7 5
Heavy
Over 1/2 Over 12.7 6
Oxygen Cutting:
Light
Under 1 Under 25 3
Medium
1 to 6 25 to 150 4
Heavy
Over 6 Over 150 5

* As a rule of thumb, start with a shade that is too dark to see the weld zone. Then go to a lighter shade which gives sufficient view of the weld zone without going below the minimum. In oxyfuel gas welding or cutting where the torch produces a high yellow light, it is desirable to use a filter lens that absorbs the yellow or sodium line in the visible light of the (spectrum) operation.

** These values apply where the actual arc is clearly seen. Experience has shown that lighter filters may be used when the arc is hidden by the workplace.