NBN EN 169 : 2003

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 Oculars with enhanced colour recognition (optional)
  5.4 Oculars with enhanced reflectance in the infrared
      (optional)
  5.5 Additional requirements for welding filters with dual
      scale number
      5.5.1 Difference in scale number
      5.5.2 Transmittance
      5.5.3 Dimensions
Annex A (informative) Guidance on selection and use
      A.1 General
          A.1.1 Scale numbers to be used for gas welding and
                braze welding
          A.1.2 Scale numbers to be used for oxygen cutting
          A.1.3 Scale numbers to be used for plasma jet
                cutting
          A.1.4 Scale numbers to be used for electric arc
                welding or air-arc gouging
          A.1.5 Scale numbers of filters to be used by
                welders' assistants
          A.1.6 Filters with enhanced colour recognition
          A.1.7 Filters with enhanced reflectance in the
                infrared
      A.2 Remarks
Annex B (normative) Relative visual attenuation quotient for
        signal light recognition
      B.1 Definition of relative visual attenuation quotient
          for signal light recognition
      B.2 Spectral functions for the calculation of luminous
          transmittance and relative visual attenuation
          quotients
Annex C (informative) Uncertainty of measurement and results
        interpretation
      C.1 Test report and uncertainty of measurement
Annex ZA (informative) Clauses of this European Standard
         addressing essential requirements or other provisions
         of EU Directives
Bibliography

Gives the scale numbers and transmittance requirements for filters intended to protect operators performing work involving welding, braze-welding, air-arc gouging and plasma jet cutting. It also includes requirements for welding filters with dual scale numbers.