Understanding EN 166: the safety standard for protective eyewear

Understanding EN 166: the safety standard for protective eyewear

Protective eyewear is an important piece of personal protective equipment in many industries. As an employer, it’s critical to choose the correct safety glasses and safety goggles to safeguard employees against a range of risks.

To make the right decisions about protective eyewear and to keep your workers and your work environment safe, and to make sure that you operate in line with strict workplace health and safety regulations, you need to understand the EN 166 safety standard and its supplementary guidelines.

All protective eyewear, including safety face shields and safety sunglasses, as well as safety glasses and safety goggles, must conform to EN 166. The most recent version of this independent standard is EN 166:2002.

Safety standards for protective eyewear explained

Safety eyewear that complies with EN 166 displays the standard on the lens and the frame. In both cases, the name of the standard is followed by a series of numbers and letters. The information included in these areas can differ.

These numbers and letters convey the type and level of protection that the lens and the frame of the safety eyewear provide. In this regard, your choice of protective eyewear should always be based on the most severe hazard that your employees will face.

These are examples of what you can expect to see on a lens and a frame and what the numbers and letters refer to:

Example of protective eyewear lens markings

Example of protective eyewear frame markings

What the numbers and letters on safety eyewear mean

The numbers and letters on EN 166-certified safety eyewear refer to four types of protective classification:

  • Field of use – this refers to the hazard that the protective eyewear safeguards the wearer against (eg. liquids, dust particles, etc.) and the type of hazard is indicated by a number (e.g. 3 for liquids)
  • Optical class – protective eyewear can be classified as having low, medium or high optical quality, which is indicated with a 1, 2 or 3
  • Mechanical strength – from low-energy impact to high-energy impact – is conveyed by a series of letters (e.g. F indicates low-energy impact)
  • Optional requirements – refers to various forms of additional protection, including hard coating and enhanced reflection, which is indicated by a series of letters (different to those used to convey mechanical strength)

Supplementary guidelines for protective eyewear

The main supplementary standards to EN 166 are EN 167 and EN 168, which detail the key optical and non-optical criteria against which EN 166-certified protective eyewear must be tested.

In addition, there are a range of secondary standards relevant to protective eyewear relating to types of safety eyewear and workplace use. Examples include:

  • EN 169 relates to protective eyewear filters
  • EN 170 relates to protective eyewear ultraviolet filters
  • EN 171 relates to protective infrared filters

Choosing protective eyewear lens materials and shades

There are some instances where lens material can be an important consideration when choosing EN 166-certified protective eyewear for employees. There are three main lens materials to be aware of, each with different properties and characteristics.

Similarly, a protective eyewear lens shade can also be a key consideration. There is a wide range of different lens shades, with each one carrying its own number and application (such as welding, oxy cutting, etc.).

For more information on EN 166, including a more detailed explanation of this standard, a full list of the supplementary guidelines, an in-depth look at the main classifications and codes, and an overview of lens material and shade categories, DOWNLOAD YOUR FREE COPY of the Contego Safety Solutions Guide to Protective Eyewear.

Why making the right choice of safety eyewear is critical

As an employer, it is your responsibility to provide your employees with the appropriate protective eyewear. Failure to do so can be disastrous: it can lead to serious accidents, injuries and even fatalities, and can have severe consequences for your company.

This is why it is critical to understand EN 166 and its supplementary guidelines. With this knowledge, you will be better positioned to ensure that your workers have the safety eyewear they need to do their jobs safely, efficiently and to the highest standard, and that your company is fully compliant with health and safety regulations and better protected against any liability.

Contego Safety Solutions stocks a wide range of corporate workwear, protective clothing and PPE, including the WEARMASTER® range. We also provide a bespoke uniform design and manufacturing service to ensure that you get precisely what you are looking for in a company uniform.

The friendly and expert team at Contego Safety Solutions is always on hand to give advice on protective eyewear. Contact us now on 0800 122 3323 or sales@contegosafety.co.uk to discuss your requirements.

Published on 26 January 2023


Contract cleaning: what’s next in hygiene standards

Contract cleaning: what’s next in hygiene standards

Workplace hygiene standards have always been a priority for managers, but the Covid-19 pandemic brought these issues under unprecedented scrutiny. New expectations around cleanliness at work are combining with other pressures to make the next 12 months a year of transformational change for the contract cleaning and facilities management sectors.

Five facilities management challenges

Five facilities management challenges

The pace of change in the Facilities Management (FM) sector shows no sign of slowing. The Covid-19 pandemic ushered in new ways of working but also triggered and accelerated several emergent trends. As a result, the FM sector now faces a series of structural challenges that will define its future.

Find out more in our new brochure