BS EN ISO 12312-2:2015 pdf free.EYE AND FACE PROTECTION – SUNGLASSES AND RELATED EYEWEAR – PART 2: FILTERS FOR DIRECT OBSERVATION OF THE SUN.
This part of ISO 12312 applies to all afocal (piano power) products intended for direct observation of the
sun, such as solar eclipse viewing.
Information on the use of filters for direct observation of the sun is given in Annex A and Annex B.
This part of ISO 12312 does not apply to the following:
a) afocal (piano power) sunglasses and clip-ons for general use intended for protection against solar radiation;
b) eyewear for protection against radiation from artificial light sources, such as those used in solaria;
c) eye protectors specifically intended for sports (e.g. ski goggles or other types);
d) sunglasses that have been medically prescribed for attenuating solar radiation;
e) prescription sunglass lenses.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 12311:2013, Personal protective equipment — Test methods for sunglasses and related eyewear ISO 4007, Personal protective equipment — Eye and face protection — Vocabulary
4 Requirements and associated test methods
41 Transmittance
4.1.1 General
The transmittance requirements of filters for the direct observation of the sun are given in Table 1. Transmittance values shall be measured or calculated at the boxed centre of the filter for normal incidence, as described in ISO 12311:2013, 7.1.1, 7.1.2, 7.3.2, 7.3.3, and 7.5.
Uncertainty of measurements of transmittance shall not be greater than 25 % of the measured value.
The measurement of spectral transmittance of filters with high optical density can be best accomplished with the use of a dual-beam spectrophotometer and comparison beam attenuators. The comparison beam attenuator should be a physical barrier, such as a perforated mesh, equivalent to a known uniform level of absorption across the entire waveband of measurement.
4.1.2 Uniformity of luminous transmittance
The relative difference in the luminous transmittance value between any two points of the filter shall not be greater than 10 % (relative to the higher value). This requirement shall apply within a circle 40 mm in diameter around the boxed centre or to the edge of the filter less the marginal zone 5 mm wide, whichever is greater.
4.2 Material and surface quality
4.2.1 Requirements
Except in a marginal area 5 mm wide, filters shall be free from defects likely to impair vision in use, such as bubbles, scratches, inclusions, dull spots, pitting, scouring, pocking, scaling, and undulations. Metal coated filter materials shall not exhibit more than one pinhole defect not greater than 200 um in average diameter within any 5 mm diameter circular zone.BS EN ISO 12312-2:2015 pdf free download.