EN 172-1994 pdf download.Personal eye protection Sunglare filters for industrial use.
This EN 172 specifies the scale numbers, transmittances and related requirements for sunglare filters for industrial use. Other valid requirements for these types of filters are specified in prEN 166.
Selection criteria and information on use of these filters are given in Annex A.
This standard does not apply to filters for protection against radiation from artificial light sources such as those used in solaria. EN 170 applies for these filters.
This standard does not apply to ski goggles for which a separate standard is in preparation or for other types used for leisure activities.
A separate standard for sunglasses and sunglare filters for general use is in preparation.
2 Normative references
This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to applies.
prEN 165, Personal eye protection — Vocabulary.
prEN 166, Personal eye protection — Specifications.
prEN 167, Personal eye protect ion — Optical test methods.
prEN 168, Personal eye protection — Non-optical test methods.
EN 169, Personal eye protection — Filters for welding and related techniques.
EN 170, Personal eye protection — Ultra-violet filter — Transmittance requirements and recommended use. CIE Publication 15 Colorimetry.
3 Designation and marking
A complete table of filter designation and marking is given in clauses 4 and 9 of prEN 166.
The scale number of a sunglare filter contains the code numbers 5 (filter with no requirement for protection in the infra-red) or 6 (filter with a requirement for protection in the infra-red) and the shade number of the filter (see clause 4 and Annex A.2).
4 Requirements
The requirements of prEN 166 apply to sunglare filters for industrial use. Only those requirements that are different from or supplement the prEN 166 specifications are given in the following.
4.1 Permissible transmittance and scale numbers
4.1.1 Filters with code number 5
See Table 1.
4.1.2 Filters with code number 6
See Table 2.
4.2 General transmittance requirements
4.2.1 Spectral transmittance
Between 500 nm and 650 nm the spectral transmittance shall not be less than 0, 2 ri,.
4.2.2 deleted
4.2.3 Recognition of signal lights
As sunglasses are often worn while driving, filters of scale numbers 5-1,1 to 5-3,1 and 6-1,1 to 6-3,1 shall meet the requirements for recognition of signal lights in addition to the protection requirements.
The relative visual attenuation quotient for signal lights red, yellow. green and blue filters of these scale numbers shall not be less than 0,8.
4.3 Special transmittance requirements
4.3.1 Photochromic filters
The luminous transmittance value of the filter in its clear state r0 and after 15 mm irradiation r1 determine the scale numbers. In 1)0th states, the requirements specified in 4.1.1 to 4.1.2 shall be met.
For photochromic filters TWT1 shall be  1,25.
When tested in accordance with Annex E.3, the change in luminous transmittance value relative to that measured initial1’ as described in E.2. shall not be greater than ±5 % for the clear state nor ±20 % for the dark state.
NOTE When checking photochromic filter materials for the other requirements of this standard, this test need not bc repeated if corresponding results are available, e.g. from the manufacturer of the raw material.
4.3.2 Polarizing filters
Where sunglasses are fitted with polarizing filters, these shall be fitted in the frame so that the plane of polarization does not deviate from the vertical, or the nominal direction if different from the vertical, by more than ±30.
For polarizing filters, the ratio of the luminous transmittance values parallel and perpendicular to the plane of polarization shall be greater than 20:1.EN 172-1994 pdf download.