In contrast to EN 471, ISO 20471 has one value (x), which indicates the class of the product. Since reflection is featured only in the highest class, the value (y) expires in ISO 20471.
EN 20471:2013 - HIGH-VISIBILITY CLOTHING
(EN 20471:2013 supersedes EN 471:2003/A1:2008.)
High-visibility clothing requirements increase visibility during the day, in the twilight, in the dark, and in poor weather conditions. High-visibility clothing has a fluorescent surface and retroreflective material that meet the certification requirements of three different classes. The applicable performance class can be obtained using a single garment or a clothing ensemble (e.g., jacket and trousers). Performance requirements are included for colour, retroreflection, and minimum HV surface area. The standard also includes directions concerning where to place HV features on protective clothing.
• X: ratio of fluorescent background material to retroreflective material (3 levels, where 3 is best)