European Standard · Eye & Face Protection
EN 169 – Welding Filters: Shade Numbers and Requirements
EN 169 is the European standard specifying requirements for filters used in welding and allied processes, protecting the eyes against intense visible light, infrared and ultraviolet radiation produced by welding arcs and flames, classified by shade number.
1. Scope
EN 169 applies to filter lenses fitted into welding shields, helmets or goggles, covering a range of shade numbers matched to different welding processes and current levels. It covers passive (fixed shade) filters, as distinct from EN 379 which covers automatic-darkening welding filters.
2. Exclusions & Related Standards
- Filters must be fitted into a certified welding shield or goggle body meeting EN 175.
- Automatic-darkening welding filters are covered by the separate standard EN 379, not EN 169.
- Often combined with head protection under EN 397 for welding helmets that double as head protection.
3. Key Requirements & Marking
Filters are marked with a shade number indicating the level of light attenuation, with higher numbers providing darker, stronger protection appropriate for higher-current welding processes. Requirements cover optical quality, spectral transmittance limits across UV, visible and infrared wavelengths, and mechanical strength.
4. Testing Overview
Testing measures spectral transmittance across ultraviolet, visible and infrared wavelengths at the specified shade number, optical quality including refractive power and diffusion of light, and resistance to physical damage appropriate to the intended use environment.
5. Selection Guide
Select the shade number according to the welding process and current level following manufacturer or regulatory shade number tables; too light a shade risks eye damage from intense radiation, while too dark a shade can make it difficult to see the weld pool clearly.
6. Inspection, Care and Maintenance
- Inspect filter lenses for scratches, cracks or discolouration that could impair vision or protection
- Replace filters that show pitting or cracking, as this can compromise both optical clarity and radiation protection
- Keep filters clean and store in a dry, protective case between uses
- Confirm the filter shade matches the specific welding process before each task
7. Frequently Asked Questions
What does the shade number on a welding filter mean?
The shade number indicates how much visible light and radiation the filter blocks, with higher numbers providing darker, stronger protection suited to higher-current welding processes.
What is the difference between EN 169 and EN 379?
EN 169 covers passive, fixed-shade welding filters, while EN 379 covers automatic-darkening welding filters that switch shade level electronically when an arc is struck.
Can I use any shade number for any welding process?
No, shade selection should follow the recommended range for the specific welding process and current level to ensure adequate protection without excessive darkness impairing visibility.
Do welding filters protect against UV and infrared radiation?
Yes, EN 169 requires specific transmittance limits across ultraviolet, visible and infrared wavelengths, not just visible light dimming.
Can welding filters be used without a welding shield?
No, filters must be mounted in a certified welding shield, helmet or goggle body meeting EN 175 to provide complete facial and eye protection.