In Europe, all personal protective equipment must be CE marked and in compliance with the PPE Directive 89/686/ EEC before they can be placed on the market. To show compliance with the basic requirements in the PPE Directive, the product can be certified to applicable, national, harmonized standards.
Welding helmets incorporating protective filters are covered by the standards EN 175, EN 166, EN 169 (passive filters) and EN 379 (auto-darkening filters).
In addition there are classifications regarding field of use
For the standards EN 166 and EN 379, optical quality of the welding filter or faceshield are classified from 1 to 3, where 1 is the best. For passive welding filters and visors, there is only one classification of optical class. For auto-darkening welding filters, there are four parts of the classification: optical class/diffusion of light/variations in luminous transmittance/angular dependence.
3M welding filters are marked with the shade range and optical classifications. Note! The following is an example from the 3M™ Speedglas™ Welding Filter SL (EN 379). Valid classification is marked on the welding filter.