EN 170:2002

Foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Designation and identification
5 Requirements
   5.1 General
   5.2 Transmittance requirements
   5.3 Ocular with enhanced colour recognition (optional)
Annex A (normative) Relative visual attenuation quotient
        for signal light recognition
Annex B (informative) Guidance on selection and use
Annex C (informative) Uncertainty of measurement and results
        interpretation
Annex ZA (informative) Clauses of this European Standard
         addressing essential requirements or other provisions
         of EU Directives
Bibliography

This European Standard specifies the scale numbers and transmittance requirements for filters for protection against ultraviolet radiation. The other applicable requirements for these types of filters are given in EN 166:1995. Guidance on the selection and use of these filters are given in Annex A. NOTE: The protective filters specified in this standard are not suitable for the direct or indirect observation of an electric arc. For this purpose a welding filter appropriate to the source being observed should be used. Such a filter would not have a scale number less than 6.