The minimum filter lens shade number used for welding depends on the specific welding process and the arc current. However, generally, a shade of 6 is the absolute minimum recommended, and that's only for very low amperage Plasma Arc Welding (PAW).
Here's a breakdown of minimum shade numbers based on welding operation and arc current, according to OSHA standards:
| WELDING OPERATION | ARC CURRENT (AMP) | OSHA MINIMUM PROTECTIVE SHADE NUMBER |
|---|---|---|
| Air Carbon Arc Cutting (CAC-A) (Heavy) | 500-1000 | 11 |
| Plasma Arc Welding (PAW) | <20 | 6 |
| Plasma Arc Welding (PAW) | 20-100 | 8 |
| Plasma Arc Welding (PAW) | 1-400 | 10 |
Important Considerations:
- Always consult the specific welding equipment manual and safety guidelines. The manufacturer may recommend a different shade number.
- Err on the side of caution. It's better to use a shade that is slightly too dark than one that is too light. If in doubt, go with the higher shade number.
- Consider ambient lighting. Brighter work environments may require a darker shade.
- Personal preference matters. Some welders prefer a slightly darker or lighter shade, even within the recommended range.
- The information above is not exhaustive. Different welding processes like Shielded Metal Arc Welding (SMAW), Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW) at varying amperages have different minimum shade requirements.
Using the correct filter lens shade is crucial for protecting your eyes from the harmful ultraviolet (UV) and infrared (IR) radiation produced during welding. Insufficient protection can lead to serious and permanent eye damage.
