High-visibility clothing: EN ISO 20471 classes
Three classes
EN ISO 20471 classifies high-visibility garments into three classes, where Class 3 offers the greatest conspicuity. The class is set by the total area of background fluorescent material and the area of retroreflective banding.
Fluorescent vs retroreflective
Fluorescent fabric works in daylight by converting UV into visible light, so it is what makes the wearer stand out in the day. Retroreflective tape returns light toward its source, which is what makes the garment visible at night under vehicle headlamps. Both are needed for around-the-clock visibility.
Choosing a class
Class 1 is the minimum for lower-risk, lower-speed environments; Class 2 is common for road-edge and warehouse work; Class 3 is required where traffic speeds are higher or the worker must be seen at the greatest distance, such as motorway maintenance.
Reading the garment
A compliant garment carries a pictogram showing the standard number and the class. If the tape or fabric has worn, faded or is no longer reflective, the garment no longer meets the class it is labelled with and should be replaced.