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It’s impossible to do welding and plasma cutting without eye protection. You’ve probably seen welders without proper welding shirts or gloves, but you haven’t seen one without a welding helmet or welding glasses yet. Welding helmets, glasses, and goggles have one thing in common: They are equipped with a dark lens that blocks harmful levels of light, including ultraviolet light.
The lens or filter is the most important part of a welding helmet. Aside from allowing you to see your weld area, it protects your eyes from intense light. Without this protection, you can suffer from corneal burns (arc eye) or blindness. However, you can wear the wrong welding glasses and hurt your eyes while welding. If you’re wearing a shade that’s too light for the kind of welding you’re doing, you’re not getting enough protection. In contrast, if you’re wearing a shade that’s too dark, you may not see the arc or the puddle properly.
You can find a review on the Best Welding Helmets on the market today here.
Lens Shade – What is it?
Lens shade is basically a measure of the darkness of the glass or filter of your welding helmet or glasses. The shades can range from 3 to 14. But the most used shades for welding are shades 9-13. These numbers are DIN ratings based on a German industrial standard in classifying light filtering levels. So when we’re talking about a shade 10 lens, it’s really a DIN 10 lens. However, you rarely hear welders saying DIN shade 10 welding glasses. You just hear, in that case, shade 10 glasses.
Safety glasses have shades as low as #3, but even at that point, most of the light is already filtered out. A shade 3 lens blocks 86% of the light. With each change in shade, you significantly lessen the amount of light through. A shade 4 lens allows almost 3 times less light than a shade 3 lens, allowing only approximately 5% of light through. If you’re using a shade 9 lens, you’re only seeing 0.037% of the light. The darkest shade commonly used in welding helmets is #13, which blocks 99.99928% of the light.
Lens Shade and Amperage
The general rule is the higher your amperage, the darker your lens should be. If you’re MIG welding at 90 amps, you need a helmet with a shade 10 lens. However, if you’re welding thick materials at 300 amps, you need a shade 13 lens. That’s because the higher the amperage, the more power you’re generating, and the more power you’re generating, the brighter the arc is. It’s not just the brightness that’s the problem. The brighter the arc, the more harmful ultraviolet and infrared radiation it releases. However, the amperage is just one factor that determines how dark your welding helmet should be.
Lens Shade and Type of Welding
Parameters vary between different types of welding. When it comes to using an appropriate welding helmet shade number, you have to be wary about how much light a welding activity produces. Although for any type of welding, you will have to use darker lenses as you increase the amperage. However, you will notice that the necessary lens shade varies between MIG, TIG, flux-core, and stick even at the same amperage. For example, MIG welding at 80 amps requires shade 10 glasses, while TIG welding at the same amperage requires #11 glasses.
Different types of welding processes produce different intensities of radiation. As mentioned earlier, the brighter the arc, the darker your helmet or glasses should be. Among welding operations, TIG emits the brightest, most intense light. Every seasoned welder knows how much faster a TIG welding arc can burn your eyes and skin. Thus, you need darker shades than you’d otherwise need for other types of operations. While you may need to use a shade 10 lens when doing flux-core welding at 125 amps, you’d need the same shade when TIG welding at as low as 20 amps!
OSHA vs ANSI/AWS
When you look at welding lens shade charts, it’s common to see the OSHA minimum protective shade number and the ANSI/AWS recommended shade number. The recommended shade numbers by ANSI and AWS are usually 2 shades darker than OSHA’s minimum shade recommendation. So, for example, if you’re stick welding at anywhere between 60 and 160 amps, OSHA requires that you wear at least a shade 8 lens. However, most people will find that these minimum recommendations from OSHA are still a tad too bright. Hence, ANSI and AWS recommend a shade 10 lens in that case. These recommendations aren’t written in stone, though. So you may find welders using lighter or darker shades than the recommended ones.
Choosing the Right Lens Shade
Whether you’re using an auto-darkening helmet or fixed shade goggles, you’ll have to deal with a number of choices. You may find shade #5 glasses being sold as welding glasses, but they’re not really suitable for any type of welding. You can wear them for low amperage plasma cutting. You may also find certain auto-darkening helmets whose shade range is 5-14, which is quite an exceptionally wide range. You can view the weld area through a shade 5 filter when grinding, and the filter will just automatically return to its previous setting once you strike an arc. Rarely used, shade 14 is the darkest and is only reserved for the most intense arcs and highest amperage welding processes and plasma cutting (1).
Welding lens shade range is 9-13 whether you’re doing MIG, TIG, stick, flux-core, or other welding operation. The following are relatively safe shade numbers to start with for different welding operations:
20-40 amps – #9
40-80 amps – #10
80-175 amps – #11
175-300 amps – #12
300-500 amps – #13
MIG and Flux Core
<80 amps – #10
80-175 amps – #11
175-300 amps – #12
>300 amps – #13
<20 amps – #9
20-40 amps – #10
40-100 amps – #11
100-150 amps – #12
>150 amps – #13
Choosing a lens shade is striking a balance between seeing the weld puddle and avoiding eye fatigue and irritation. If you can’t see the weld puddle or you have to stick your nose too close to the workpiece, you’re using a shade that’s too dark. On the other hand, if the arc seems too bright, you probably need to up the shade.