How Does Hi Vis Work? The Science Behind Staying Seen
Hi vis isn’t just a colour choice—it’s a life-saving layer of protection for thousands of workers across the UK and Ireland. From construction sites to roadside repairs, hi vis workwear plays a crucial role in keeping tradespeople safe, visible, and compliant.
But how exactly does it work?
At Tradeworx, we stock a wide range of hi vis clothing from leading brands like Snickers, Blåkläder and Portwest. In this blog, we’ll break down the science behind high visibility gear, and help you choose the right kit for your job.
What Is Hi Vis?
Hi vis (short for high visibility) clothing is specially designed to make the wearer stand out in any environment—especially those with low light or high risk, such as:
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Construction and road sites
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Railways
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Warehouses and logistics centres
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Utility and emergency services
It’s not just about being seen—it’s about being seen clearly and quickly, giving others enough time to avoid accidents.
The Three Elements of Hi Vis
1. Fluorescent Fabric
Fluorescent materials—usually yellow or orange—react with UV light to appear brighter in daylight. They enhance contrast, making the wearer pop out from the background even in cloudy or low-light conditions.
The Portwest T400 PW3 Hi Vis Winter Jacket – Yellow is a perfect example. Its vivid yellow fabric helps workers stay seen in dim winter conditions, while the insulated lining keeps them warm.
2. Reflective Tape
This is what makes you visible at night. Reflective strips bounce light back to its source—like a car’s headlights—alerting drivers that someone is there.
Hi vis trousers like the Snickers High-Vis Class 2 Stretch Trousers with Holster Pockets in Yellow/Black feature strategically placed reflective tape to ensure visibility from all angles, even in pitch black conditions.
3. Contrast Design
Most hi vis gear includes dark panels on the knees, cuffs, or bottom edges. These don’t just look sharp—they hide dirt and wear in high-contact areas, helping the gear maintain visibility longer.
When Does Hi Vis Work Best?
Hi vis is most effective in low-light or high-traffic situations. You’ll often see it on early morning or night shifts, in winter months, or anywhere vehicles and machinery are in motion.
But visibility isn’t just about brightness—it’s about movement. A bright yellow hoodie, for example, draws attention to your upper body, which tends to move more than your legs.
That’s why garments like the Snickers High-Vis Class 2 Full Zip Hoodie are ideal for layering—offering both flexibility and visibility when it matters most.
Staying Compliant on Site
Hi vis garments are categorised into three EN ISO 20471 classes:
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Class 1 – Lowest visibility, for low-risk environments
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Class 2 – Medium visibility (e.g. hi vis trousers or vests)
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Class 3 – Highest visibility (e.g. full jackets or combined garments)
For many construction sites, Class 2 or 3 is mandatory. That’s why it’s important to choose clothing that’s not just comfortable but certified to the correct safety standard.
👉 Explore our full range of certified hi vis clothing here
Final Word: Hi Vis That Works When You Do
Hi vis clothing works by combining fluorescent colour, reflective tape, and clever design to help others spot you—fast. Whether you’re on a scaffold, operating heavy machinery, or directing traffic, being visible can be the difference between safety and danger.
At Tradeworx, we stock a handpicked selection of hi vis workwear designed for tradespeople who need performance, comfort, and safety—without compromise.
Shop hi vis jackets, trousers, hoodies and more from trusted brands like Snickers, Blåkläder, and Portwest.