If you work on a UK construction site, wearing the correct hi-vis clothing isn’t just good practice — it’s a legal requirement under the Personal Protective Equipment at Work Regulations 1992. This guide breaks down everything you need to know about hi-vis standards, classes, and what to look for when buying workwear in the UK.
What Are EN ISO 20471 Classes?
Hi-visibility clothing in the UK is rated under EN ISO 20471 — the international standard for high-visibility warning clothing. There are three classes:
- Class 1 — Minimum visibility. Suitable for low-risk environments with slow-moving traffic or well-lit areas. Includes vests with minimal reflective tape.
- Class 2 — Medium visibility. Required on most construction sites. Includes waistcoats, jackets, and trousers with 360° visibility.
- Class 3 — Highest visibility. Mandatory near fast-moving traffic or poor visibility conditions. Full-coverage garments with maximum reflective tape area.
Do I Need Hi-Vis on a UK Construction Site?
Yes. The Construction (Design and Management) Regulations 2015 require principal contractors to ensure all workers on site wear appropriate PPE, including hi-vis where there’s a risk of being struck by vehicles or plant machinery. Most UK sites mandate Class 2 as a minimum for ground workers and Class 3 near road-level operations.
Choosing the Right Hi-Vis Vest
When buying hi-vis for UK construction sites, check for:
- EN ISO 20471 certification — must be printed on the label
- Background material colour — yellow or orange fluorescent fabric
- Retroreflective tape width — minimum 50mm for Class 2 & 3
- Durability — look for reinforced seams and wash-resistant fabric
- Fit — should allow layering over PPE in winter without restricting movement
Hi-Vis Jackets vs Vests: Which Is Better?
For summer or warm sites, a hi-vis vest worn over a base layer is standard. For winter or outdoor sites, a hi-vis jacket — ideally waterproof and padded — provides warmth while maintaining visibility. Many UK contractors opt for a hi-vis softshell jacket as a year-round option that layers easily.
How Often Should Hi-Vis Be Replaced?
Hi-vis garments degrade over time. The fluorescent fabric loses brightness with UV exposure and washing, while reflective tape can peel or crack. Industry guidance suggests replacing hi-vis workwear:
- Every 6–12 months for daily use on outdoor sites
- Immediately if tape is peeling, fabric is faded, or the garment is damaged
- After any contamination with oil, paint, or chemicals that reduces reflectivity
Buy EN-Certified Hi-Vis from HDZ Group
At HDZ Group, all our hi-vis vests, jackets and trousers are EN ISO 20471 Class 2 & 3 certified. We supply individual workers and construction companies across the UK, with bulk pricing from 5 units and next-day delivery on most items. Browse our hi-vis range or contact us for a trade quote.