The darkness of welding filters is indicated by the shade number; the higher the number, the darker the filter. Fixed welding lenses are covered by EN 169, auto-darkening filters by EN 379 and the helmet body by EN 175 (the transition to the new ISO 16321 series is ongoing). The correct shade is chosen according to the welding process and current; refer to the EN 169 table in the product's instructions. OSHA's principle: start with a shade too dark to see the weld zone, then move to a lighter shade that gives sufficient visibility without going below the minimum.
The table below shows the minimum shade recommendations from the US occupational safety agency OSHA's 29 CFR 1910.133 regulation. In Europe the EN 169 table is used and the values are not identical; always follow the table in your product's instructions.
| Welding process | Current | Minimum shade |
|---|---|---|
| Covered electrode (MMA / SMAW) | Below 60 A · 60–160 A · 160–250 A · 250–550 A | 7 · 8 · 10 · 11 |
| Gas metal arc (MIG/MAG / GMAW) and flux-cored (FCAW) | Below 60 A · 60–160 A · 160–250 A · 250–500 A | 7 · 10 · 10 · 10 |
| TIG (GTAW) | Below 50 A · 50–150 A · 150–500 A | 8 · 8 · 10 |
| Plasma cutting | Below 300 A · 300–400 A · 400–800 A | 8 · 9 · 10 |
| Plasma welding | Below 20 A · 20–100 A · 100–400 A · 400–800 A | 6 · 8 · 10 · 11 |
| Gas welding (thin · medium · thick) | – | 4 · 5 · 6 |
| Oxygen cutting (thin · medium · thick) | – | 3 · 4 · 5 |
| Brazing · soldering | – | 3 · 2 |
Note on Optrel's EN 169 table: depending on the welder's perception, one shade higher or lower may be used.
Example marking: 4/9-13 OS 1/1/1/2 EN 379
| Part | Meaning |
|---|---|
| 4 | Shade in the light (idle) state |
| 9-13 | Adjustable shade range in the dark state |
| OS | Manufacturer code |
| 1/1/1/2 | Optical class, diffusion of light (scatter) class, homogeneity and angle dependence, respectively (1 is best) |
| EN 379 | Standard number |
On the helmet shell you will see a marking such as "EN 175 B"; B indicates medium-energy impact resistance. The protective outer lens carries the "EN 166" marking.
Annex 3 of the PPE Regulation in Türkiye lists eye and face protection for welding work ("welding, grinding and separating work"), leather aprons and gloves, and fire-resistant protective clothing for welding in confined spaces. Products:
Luxe auto-darkening welding helmet (ADF) · Starline YC-80 welding head shield · Starline welding helmet lens · Leather welder's apron · Welder's sleeves.It depends on the process and the current; for example, OSHA minimum values are shade 8 for stick welding (coated electrodes) at 60–160 A and shade 10 for MIG/MAG (gas metal arc) welding at the same current. Always follow the EN 169 table for your product.
It means an auto-darkening filter with shade 4 in the light state, adjustable between shade 9 and 13 in the dark state.
According to Optrel, UV and IR protection is always maintained regardless of the selected shade; the dark shade protects against the brightness of the arc.
Sources:OSHA 29 CFR 1910.133 · Optrel p550neo user instructions (EN 169 table, EN 379 markings) · JSP welding protection · Ministry of Labour and Social Security (ÇSGB) PPE Portal – Eye and face · PPE Regulation and annexes (mevzuat.gov.tr)
This guide was prepared by Vitrin Online on 10.10.2026. It provides general information only and is not legal advice. Always follow the product's user instructions and your workplace risk assessment.
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