Why Has the EN 166 Been Replaced?

Since its introduction in 2001, EN 166 has been the leading European standard for the certification of eye protection. Over the past 25 years, however, working conditions, materials and risk profiles have changed dramatically. With a stricter policy, EN ISO 16321-1 responds to these changes. In addition, the EN 166 was a purely European standard. The EN ISO 16321-1 was developed to harmonize not only European but also global safety requirements for eye protection.

What Does EN ISO 16321-1 Mean Exactly?

The EN ISO 16321-1 is the new international standard for personal eye and face protection for professional use. The standard replaces not only the EN 166 but also related standards such as EN 170, EN 171, EN 172 and EN 379, so there is now a single standard for almost all forms of eye protection in work environments.

Until November 2025, safety glasses could still be certified under EN 166, and from that date, all new safety glasses must comply with EN ISO 16321-1 to be certified. Eyeglasses that have already been certified under EN 166 remain valid until the end of the five-year certification period.

The Main Differences Between EN 166 and EN ISO 16321-1

The transition is more than just a number change. For example, the field of application has been tightened, the optical requirements are stricter and the markings have been expanded. One of the most important changes is that the impact tests have become tougher. Under the EN 166, a steel ball weighing approximately 43 grams was used. The new standard uses a projectile weighing approximately 66 grams in the basic impact test. In addition, EN ISO 16321-1 also requires a larger protective surface than EN 166, which provides better eye and face coverage. This is particularly relevant in environments where employees are at risk of particles flying around.

New Markings: What Has Changed?

Not only have the test methods been tightened, but the markings have also changed. Each certified safety goggle has markings engraved on the lens and frame. These markings are mandatory and indicate what the glasses can do and what situations they are suitable for.

Markings must be clearly and indelibly so that the user can easily determine whether glasses are suitable for certain working conditions. The most notable change in the marking is in the impact classes. Under EN ISO 16321-1, the impact levels have been reclassified. The familiar letters F, S and B in the EN 166 make way for C, D and E. This results from the stricter impact testing methods.

Markings on Our Lenses and Frames

At Seeh, we did not wait for the transition to EN ISO 16321-1. All the new frames in our collection are already certified according to the new standard, including CE marking. The integrated side covers, the larger protection zones and the improved fit are included as standard. Safety and comfort go hand in hand with our prescription safety glasses. Our frames are not only approved in accordance with the most stringent requirements, but also offer optimal comfort due to their light weight. This leads to a high level of user acceptance.

Do You Have any Questions About the EN ISO 16321-1?

Do you want to know whether the safety glasses in your organization already meet the new standard? Our specialists are happy to think along with you. Get in touch via service@seeh.nl or call us at +31 (0) 85 065 30 56.