Filter Lenses for Protection Against Radiant Energy | |||
Operations | Electrode Size 1/32 in. | Arc Current | Minimum* Protective Shade |
Shielded metal arc 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 arc 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 arc 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-inches | 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 workpiece.
29 C.F.R. §1910.133