Hi-vis clothing is graded into three classes under EN ISO 20471, based on how much fluorescent fabric and reflective tape a garment carries. Class 1 is the lowest visibility (low-risk, off-road work), Class 2 covers most roadside and public-area tasks, and Class 3 is the highest, required for high-speed traffic, low light, and rail. The class your team needs comes down to one thing: the risk in their working environment.
What is EN ISO 20471?
EN ISO 20471 is the UK and European standard for high-visibility clothing. It replaced the older EN 471 standard and sets the test methods and design rules that make a garment conspicuous both in daylight and in vehicle headlights at night.
Two materials do the work. Fluorescent background fabric (the bright yellow, orange or red) handles daytime visibility, and retroreflective tape bounces vehicle headlights back to the driver after dark. A garment's class is set by how much of each it carries and how they're laid out on the body. The more of both, and the better the coverage, the higher the class.
What are the three hi-vis classes?
There are three classes under EN ISO 20471, each defined by a minimum area of fluorescent fabric and reflective tape. Class 1 carries the least and suits the lowest-risk work; Class 3 carries the most and is built for the highest-risk environments. The figures below are the certified minimums.
Hi-vis class comparison table
|
Class |
Min. fluorescent fabric |
Min. reflective tape |
Typical garment |
Suitable for |
|
Class 1 |
0.14 m² |
0.10 m² |
Hi-vis trousers, some waistcoats |
Low-risk, off-road: warehouses, car parks, slow controlled traffic |
|
Class 2 |
0.50 m² |
0.13 m² |
Hi-vis vests and waistcoats |
Public roads up to ~60 km/h, general site work, delivery |
|
Class 3 |
0.80 m² |
0.20 m² |
Long-sleeve jackets, coveralls (or vest + trousers combined) |
High-speed traffic, motorways, rail, poor light, emergency response |
A key practical point: a single garment doesn't have to hit Class 3 alone. A Class 2 vest worn with Class 1 hi-vis trousers can combine to meet Class 3 coverage, as long as both are certified and worn together. That's often the most comfortable way to get a worker to full Class 3 visibility.
Which hi-vis class does my team need?
Match the class to the risk, not to habit. The deciding factors are traffic speed, light levels, and how exposed the worker is to moving vehicles. Here's the quick decision guide:
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Class 1 - off-road or tightly controlled environments where vehicles are slow and few: warehouses, internal logistics, car parks, some landscaping.
-
Class 2 - the workhorse class. Work on or beside public roads up to around 60 km/h, general construction, delivery drivers, and most site visitors. A hi-vis vest certified to Class 2 covers a huge share of UK jobs.
-
Class 3 - high-speed roads and motorways, any work in poor light or at night, and any role with significant vehicle exposure. This usually means a full-sleeve hi-vis jacket or a vest-and-trouser combination.
If you're ever unsure between two classes, go higher. The cost difference is small next to the consequences of being under-protected, and over-specifying visibility is never the thing that gets flagged in an incident review.
What are the UK regulations on high-visibility clothing?
Hi-vis is legally classed as personal protective equipment, so it falls under the Personal Protective Equipment at Work Regulations 1992 (amended 2022). Where a risk of being struck by a vehicle remains after you've done what you can with site layout and traffic management, the employer must provide suitable hi-vis free of charge, keep it clean and serviceable, and store it properly.
UK law is risk-based rather than prescriptive: there's no blanket "everyone wears Class 3" rule. You assess the hazard and provide the class that controls it.
Do railway workers need a special hi-vis class?
Yes. Trackside rail work has its own standard, RIS-3279-TOM, on top of EN ISO 20471, owned by the Rail Safety and Standards Board. It's stricter in two ways: the garment must be a minimum of Class 2, and it must be fluorescent orange specifically, because orange stands out best against the lineside environment. Standard yellow hi-vis, whatever its class, isn't compliant for trackside work. If any of your team work on or near the railway, check the garment is certified to RIS-3279-TOM, not just EN ISO 20471.
How do you keep hi-vis compliant over time?
A hi-vis garment is only doing its job while the fluorescent fabric stays bright and the reflective tape stays intact. Both fade with washing, UV exposure and wear, and a washed-out vest can drop below its certified performance long before it looks worn out.
To keep kit compliant:
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Inspect regularly for faded fabric, cracked or peeling tape, and ingrained dirt that dulls fluorescence.
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Follow the wash care label and respect the maximum wash cycles the manufacturer states.
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Replace garments that have faded, not just ones that are torn.
Good care also protects any branding. If your hi-vis carries your company logo, washing it properly keeps both the safety performance and the print or embroidery looking sharp. how to care for your workwear
Frequently asked questions
What is the difference between Class 2 and Class 3 hi-vis?
Class 2 carries at least 0.50 m² of fluorescent fabric and 0.13 m² of reflective tape, and suits roadside and general site work up to about 60 km/h. Class 3 carries at least 0.80 m² of fluorescent fabric and 0.20 m² of reflective tape with fuller body coverage, and is required for high-speed traffic, low light, and rail.
Is a hi-vis vest Class 2 or Class 3?
Most standalone hi-vis vests are Class 2. To reach Class 3, you generally need a long-sleeved jacket or coverall, or a certified Class 2 vest worn together with Class 1 hi-vis trousers so the combined coverage meets the Class 3 minimum.
Is hi-vis a legal requirement in the UK?
Not automatically. Hi-vis is required where a risk assessment shows workers could be struck by vehicles and that risk can't be removed by other means. Where it is required, the employer must provide it free of charge under the PPE at Work Regulations.
What hi-vis do railway workers need?
Trackside rail workers need orange hi-vis certified to RIS-3279-TOM, minimum Class 2. Standard yellow EN ISO 20471 garments are not compliant for work on or near the railway.
Does washing reduce hi-vis effectiveness?
Yes. Repeated washing and UV exposure fade the fluorescent fabric and degrade the reflective tape, which can push a garment below its certified class. Follow the care label, respect the stated maximum wash cycles, and replace faded garments even if they aren't damaged.