Standard explainer · EN ISO 20471
The standard behind every compliant hi-vis garment comes down to a simple idea: enough bright fabric to be seen by day, enough reflective tape to be seen at night. Here's exactly what it measures, and how the three classes fall out of it.
What it measures
EN ISO 20471 is the standard for high-visibility clothing for professional use. It sets performance for two materials that do different jobs:
A garment must carry a minimum area of each, and both must meet minimum colour, luminance and retroreflection performance.
The class table
The class is how much of each material the garment carries — minimum areas for the highest-performing garment in each class.
| Class | Background (fluoro) | Retroreflective | Typical garment |
|---|---|---|---|
| Class 1 | 0.14 m² | 0.10 m² | Trousers or light band set |
| Class 2 | 0.50 m² | 0.13 m² | Waistcoat / vest |
| Class 3 | 0.80 m² | 0.20 m² | Sleeved garment, or jacket + trousers |
Colours & certification
Three fluorescent backgrounds are permitted — yellow, orange-red and red — each within defined colour and luminance limits. Rail and much highways work call for orange; general industry leans yellow. Because hi-vis is PPE, compliant garments carry a UKCA (or CE) mark with the standard reference.
The wash-cycle limit
Both materials degrade — fluorescent dye fades under UV and washing; tape cracks and dulls. So garments are marked with a maximum number of wash cycles. A garment past its rating, visibly faded, or with cracked tape should be treated as non-compliant and replaced, regardless of how yellow it looks.
Questions
The minimum area of fluorescent background fabric (daytime conspicuity) and the minimum area of retroreflective material (night visibility). A garment's class depends on carrying enough of both, plus minimum photometric and colour performance.
Rarely. Class 3 needs about 0.80 m² of background, which a sleeveless waistcoat can't provide. Class 3 is achieved with sleeves, or by combining a compliant jacket with hi-vis trousers.
Fluorescent yellow, orange-red and red, each with defined colour and luminance limits. The choice is often driven by sector — rail and some highways work specify orange.
EN ISO 20471 Class 1–3 in yellow and orange, with embroidery or print and trade-account ordering.