What EN ISO 20471 actually classifies
EN ISO 20471 is the current European standard for high-visibility clothing, and it classifies garments by class (1, 2 or 3) based on the minimum area of background (fluorescent) material and retroreflective material the garment provides — not by colour alone. A garment's class is therefore about how much visible area it covers, in both daylight (via the fluorescent background material) and low-light or headlight conditions (via the retroreflective strips), rather than a subjective "how bright does it look" assessment.
Class 1, 2 and 3 — matching class to risk
Class 1 is the minimum coverage level and suits lower-risk environments away from moving traffic, such as a warehouse aisle with pedestrian-only foot traffic. Class 2 steps up coverage and suits moderate-risk settings — parking areas, sites with occasional vehicle movement. Class 3 provides the greatest coverage — typically a garment combining a jacket or coverall with full sleeve coverage — and is specified for the highest-risk environments, most commonly roadside and highway work, where visibility to fast-moving traffic in poor conditions is critical. Site risk assessment, not personal preference, should drive the class selected.
Colour and combining garments
The standard permits fluorescent orange-red, yellow, and a combination of the two as background colours — the choice is often driven by site convention, contrast against the background environment (orange stands out better against green/rural backgrounds, yellow against grey urban/industrial settings), or company branding, rather than the standard itself mandating one colour. Where a single garment doesn't provide enough coverage area on its own, the standard also allows combining separate certified garments (for example a vest over a jacket) to reach the required class, provided the combination is itself tested and rated together.