The new EN ISO 16321 standard has been officially in force since 11 November 2025. It replaces the long-standing EN 166, which served as the foundation for eye and face protection across Europe for more than 20 years. The updated standard introduces stricter testing procedures, improved ergonomic requirements, and enhanced levels of protection for workers across a wide range of industries.
In this article, you’ll discover exactly what has changed, why the new standard matters, and what businesses need to do to ensure compliance.
Why was EN ISO 16321 introduced?
Risks in the workplace have evolved significantly in recent years. Machinery has become more powerful, processes faster, and counteracting exposure to impact, dust, heat, and chemicals is increasingly challenging. The new EN ISO 16321 standard addresses these challenges through:
- More realistic impact testing
- Stricter optical and thermal requirements
- Improved ergonomics and fit
- Extended UV and IR protection
A transition period, which allowed EN 166 and EN ISO 16321 to coexist, ended on 11 November 2025. Since that date, EN ISO 16321 is now the only valid standard for new certifications.
Overview of EN ISO 16321
The new standard consists of three sections:
- EN ISO 16321‑1: General requirements for eye and face protection
- EN ISO 16321‑2: Protection for welding and allied technologies
- EN ISO 16321‑3: Requirements for mesh protection
More rigorous and realistic impact testing
Impact testing under EN ISO 16321 has become more rigorous, and better aligned with real-life working conditions. One key change is the use of a heavier steel ball, making the European standard more comparable to the American ANSI Z87.1 standard.
The impact categories have been renamed:
| Old (EN 166) | New (EN ISO 16321) | Speed | Protection zone |
|---|---|---|---|
| F | C | 45 m/s | Orbital Protection Zone (OPZ) |
| B | D | 80 m/s | Extended Orbital Protection Zone (EOZ) |
| A | E | 120 m/s | Face Protection Zone (FPZ) |
This new classification makes it easier to select the right safety glasses based on an accurate risk assessment.
Improved fit and ergonomics
An important change is the increase from two to six test headforms. This enables manufacturers to test products on a wider variety of face shapes and sizes.
This ensures:
- Greater wearer comfort
- Fewer pressure points
- Improved sealing against dust and liquids
- A more secure fit during intensive tasks
A wider field of vision and enhanced comfort
The required field of vision has been increased, enabling wearers to maintain more natural peripheral vision. This reduces fatigue and increases wearer comfort.
In addition:
- Ventilation openings are now limited to a maximum of 1.5 mm
- Headbands must be adjustable or self-adjusting
New optional performance
The standard introduces additional voluntary performance tests that further extend the protective capabilities of eye and face protection:
| New performance | Code | Description |
|---|---|---|
| Chemical resistance | CH | Tested against specific chemicals |
| Heat radiation | 7 | Protection against exposure to intense thermal sources |
| High Mass Impact | HM | Large objects at low speed |
| Anti-fog | N | Prevents condensation |
| Splashes and liquids | 6 | Replaces the old “3” |
The coding for protection against molten metals and hot solids (9) has been retained.
Enhanced UV and IR‑protection
The requirements for UV‑ and IR‑ filters have become stricter. Maximum transmittance between 200 and 365 nm is now limited to <0.1%, including clear (transparent) lenses. This provides a higher and more consistent level of protection — particularly important for outdoor workers or workers exposed to artificial UV‑sources.
Prescription safety glasses are now officially included
For the first time, prescription (corrective) safety glasses are explicitly included within the scope of the standard. They must comply with:
- Optical accuracy
- Correct centring
- Frame-lens compatibility
- Maintaining impact resistance and UV‑protection
As a result, professionals who require visual correction no longer need to choose between clear vision and certified protection.
What does this mean for businesses in 2026?
Now that the standard has been in force for several months, businesses should take the following action to ensure full compliance:
- Evaluate current eye and face protection equipment
- Assess which existing models still meet operational needs
- Phase out older EN 166‑models from future procurement
- Align all new orders with EN ISO 16321
- Request updated compliance documentation and certificates from suppliers
Products previously certified under EN 166 may continue to be used until the end of their service life. However, all new certifications must comply with EN ISO 16321.
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