What’s changing?
The longstanding eye protection standard EN 166:2001 is being replaced by EN ISO 163211 (plus related parts for welding/mesh protectors).
On 11 November 2025, EN ISO 16321 became the standard used for new certifications in the UK and EU, replacing EN 166.
What changes will you notice?
1) New standard number on new eyewear
When you buy new safety glasses/goggles/face shields, you’ll increasingly see EN ISO 16321 listed instead of EN 166.
2) Potentially better fit and comfort
The new standard uses six head-form sizes in testing (rather than the old approach), designed to better reflect a wider range of people. This may lead to improved fit options, as well as cleared guidance from manufacturers.
3) Clearer markings for what the eyewear can do
Expanded product markings may include codes that can cover things like fogging resistance, chemical exposure, streams of liquid, radiant heat, and other performance claims.
Simply buying checks: what to look out for
When ordering new eye protection, check:
- It’s certified to EN ISO 16321 (or the relevant part if it’s for welding/mesh protection).
- Make sure it carries a ‘CE’ or ‘UKCA’ mark.
- The product markings match your risk (e.g., impact, splashes, heat, fogging). The new standard supports more detailed marking for these features.
- Comfort/fit is considered, especially if staff struggle with sealing, slipping, or misting. Fit testing improvements are highlighted as a key change.
Is it OK to keep using EN 166 eyewear?
Yes, in most cases. Existing products certified to EN 166 can continue to be sold until their certification expires, for up to a maximum of five years from the certificate issue date. This could mean products stay valid into late 2029, depending on when the certificate was issued.
Practical workplace approach:
- You don’t need to replace eye protection just because the standard name changed.
- Keep using EN 166 eyewear if it’s still suitable for the task and in good condition, and switch to EN ISO 16321 certified products as you replenish stock (this is good practice; your risk assessment and manufacturer instructions still apply).
