R 408.13312a Filter lenses.

Rule 3312a. (1) An employer shall ensure that each affected employee uses equipment that has filter lenses which have shade numbers appropriate for the work being performed for protection from injurious light radiation. (2) Table 1 is a listing of appropriate shade numbers for various operations. (3) Table 1 reads as follows: TABLE 1 FILTER LENSES FOR PROTECTION AGAINST RADIANT ENERGY OPERATIONS PLATE THICKNESS (INCHES) PLATE THICKNESS (MM) MINIMUM* PROTECTIVE SHADE Gas Welding: Light Medium Heavy Under 1/8 1/8 to 1/2 Over 1/2 Under 3.2 3.2 to 12.7 Over 12.7 4 5 6 Oxygen Cutting Light Medium Heavy Under 1 1 to 6 Over 6 Under 25 25 to 150 Over 150 3 4 5 OPERATIONS ELECTRODE SIZE 1/32 IN. ARC CURRENT MINIMUM* PROTECTIVE SHADE Shield metal Arc welding Less than 3 3 to 5 more than 5 to 8 more than 8 Less than 60 60 to 160 161 to 250 251 to 550 7 8 10 11 Gas metal arc welding and flux cored arc welding Less than 60 60 to 160 161 to 250 251 to 500 7 10 10 10 Gas tungsten arc welding Less than 50 50 to 150 151 to 500 8 8 10 Air carbon Arc cutting (Light) (Heavy) Less than 500 500 to 1000 10 11 Plasma arc welding Less than 20 20 to 100 101 to 400 401 to 800 6 8 10 11 Plasma arc cutting (Light)** (Medium)** (Heavy)** Less than 300 300 to 400 401 to 800 8 9 10 Torch brazing Torch soldering Carbon arc welding 3 2 14 * As a rule of thumb, start with a shade that is too dark to see the weld zone. Then go to a lighter shade that gives a 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 light filters may be used when the arc is hidden by the workpiece.