EN ISO 16321 and EN 166 explained: safety glasses and goggles
EN ISO 16321 and EN 166 explained: safety glasses and goggles
EN ISO 16321 replaced EN 166 as the standard for occupational eye and face protection. EN 166 was removed from the GB and EU lists on 11 November 2025.
Updated
Standards on this page
Symbols follow the official pictograms where one exists.
Quick answer
EN ISO 16321-1 covers general eye and face protection, Part 2 adds welding and Part 3 covers mesh protectors. Eyewear marked only EN 166 was certified to the old standard; existing certificates can stay valid until they expire, but new assessments use EN ISO 16321. On EN 166 frames, F means low-energy impact, B medium and A high, while K is anti-scratch and N anti-fog.
At a glance
| Detail | |
|---|---|
| What it covers | Safety glasses, goggles, face shields, welding filters and mesh visors |
| Current standard | EN ISO 16321-1:2022+A1:2025, -2:2021, -3:2022+A1:2026 |
| EN 166:2001 | No longer designated in GB or harmonised in the EU (since 11 November 2025) |
| On the label | "ISO 16321" markings on frame and lens, or "EN 166" with impact letters on older stock |
Common EN 166 markings you will still see
| Mark | Meaning |
|---|---|
| F | Low-energy impact (45 m/s) |
| B | Medium-energy impact (120 m/s) |
| A | High-energy impact (190 m/s) |
| K | Anti-scratch |
| N | Anti-fog |
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EN ISO 16321 and EN 166 questions
Can I still use EN 166 safety glasses?
Yes, if they are in good condition. The change affects new certifications, not kit already in use.
What does F on safety glasses mean?
Low-energy impact protection under EN 166, tested at 45 metres per second.
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Official sources
Standards and site rules change. Always check the current edition, the product's declaration of conformity and your own risk assessment.
- GOV.UK: Designated standards for PPE (Great Britain): https://www.gov.uk/government/publications/designated-standards-ppe
- European Commission: Harmonised standards for PPE (EU, applies in Ireland and Northern Ireland): https://single-market-economy.ec.europa.eu/single-market/goods/european-standards/harmonised-standards/personal-protective-equipment_en
- HSE: PPE at work regulations: https://www.hse.gov.uk/ppe/ppe-regulations-2022.htm
- HSA: Personal protective equipment (Ireland): https://www.hsa.ie/eng/topics/personal_protective_equipment_-_ppe/
- BSI: the UK National Standards Body (publishes BS EN standards): https://www.bsigroup.com/en-GB/about-bsi/uk-national-standards-body/
- NSAI: National Standards Authority of Ireland (publishes I.S. EN standards): https://www.nsai.ie/