Pick the wrong work welly and you pay for it. You get turned away from site. Or worse — you get hurt. Dunlop makes more of the UK's work wellies than any other brand. This guide covers the S4 and S5 safety ratings in plain English, explains Purofort and Acifort materials, runs through the right boot for each job, and shows you how to get the fit right. Read it once. Buy right first time.
Why your employer has to give you the right welly
This is law, not guidance. Under the Personal Protective Equipment at Work Regulations 1992, employers must provide suitable safety footwear where a risk assessment identifies the need. Farming, food factories, construction sites, cold stores — anywhere with a foot hazard qualifies.
Your employer picks the boot. You wear it. If you're self-employed, the duty falls on you.
The standard those boots must meet is EN ISO 20345. Every safety welly in this guide is tested against it. The HSE guidance on slip-resistant footwear is clear: don't pick boots from a brochure alone. Match the sole to your actual floor surfaces and conditions.
S4 or S5: which rating do you actually need?
Safety wellington boots are Class II footwear. That means the whole boot — upper and sole — is moulded from rubber or polymer as one unit. No join lines. No stitching to let water in. Fully waterproof by design.
The two ratings you'll see on work wellies are S4 and S5. Here's what each gives you.
S4 — the baseline safety welly
S4 gives you four built-in protections under EN ISO 20345:
- Steel toe cap — survives a 200-joule impact. That's a 20 kg weight dropped from 1 metre onto your toes.
- Antistatic properties — bleeds static charge safely away from your body.
- Energy absorption at the heel — cushions impact when you step down hard.
- Fuel oil resistance (FO) — the outsole won't break down in oil or diesel. This is part of the S4 definition under both the 2011 and 2022 versions of the standard.
S4 suits jobs where you need waterproofing and toe protection. Sharp debris on the ground is not a regular hazard for S4 wearers.
S5 — add a midsole
S5 is S4 plus two extras:
- Penetration-resistant midsole — a steel plate in the sole. It must resist 1,100 Newtons of force. That stops a nail going straight through. Cheap wellies don't have this.
- Cleated outsole — deeper tread for grip on mud and uneven ground.
S5 is the call for construction, agriculture, and any site where nails, rebar, or sharp metal offcuts are underfoot. Not sure which you need? Go S5. You can wear an S5 boot anywhere an S4 is needed. The reverse isn't true.
For more on steel toe options across the Dunlop range, see our guide to Dunlop steel toe wellies.
What about S5L and the 2022 standard?
EN ISO 20345:2022 was harmonised in the UK in 2023. It builds on the 2011 version rather than replacing it overnight. Boots certified to the 2011 standard are still fully legal. No certificate runs past November 2029. Employers don't need to replace 2011-certified boots that are still in date.
The 2022 update added a useful new rating: S5L. That's S5 with a non-metallic composite midsole instead of a steel plate. The composite still passes the 4.5 mm nail test. But it won't trigger metal detection gates. If your site runs floor-level ferrous detectors — common in food and pharmaceutical factories — S5L is worth looking at. The 2022 update also introduced LG (Ladder Grip) marking and replaced the old SRA/SRB/SRC slip ratings with a single SR mark.
Dunlop materials explained: Purofort, Acifort and PVC
Not all Dunlop wellies are the same material. There are three families. Each sits at a different price point and does a different job. See them side by side in the full Dunlop safety footwear range.
PVC — the entry level
PVC is the cheapest option. Heavy, stiff in the cold, and weak on heat retention. Fine for short jobs where you need waterproofing and basic safety. Not the right choice for all-day wear.
The Dunlop Work-It is the go-to PVC S5 boot. Steel toe, steel midsole, cleated outsole. Certified to EN ISO 20345:2022. A solid start for sites that need S5 on a tight budget.
Dunlop Work-It Full Safety Wellington S5 Steel Toe Waterproof Boot
Acifort — better chemical resistance
Acifort is Dunlop's blend of PVC, nitrile rubber, and polymers. The nitrile rubber does the real work. It handles chemicals — oil, fat, blood, fertilisers — far better than plain PVC. The boot also lasts longer.
Acifort is the step up for agriculture and food environments. Heavier than Purofort, but tougher against chemical attack. Worth knowing: the Acifort MetGUARD adds metatarsal and ankle protection to the Acifort base. But the MetGUARD carries an SB safety rating — steel toe cap, but the base class is SB, not S5. Check the label before ordering for sites that require S5.
Purofort — the best all-day boot
Purofort is Dunlop's own material. It's a polyurethane foam with millions of tiny air pockets locked into a cross-linked structure. Those air pockets do two things: they make the boot up to 35% lighter than PVC, and they trap warmth.
Standard Purofort models carry a CI (cold insulation) rating down to -20°C. Purofort is flexible and shapes to your foot over time. For all-day wear in UK conditions, it's the material to look for.
One honest note: Purofort lasts best when kept away from diesel, petrol, and other hydrocarbons. Fuel breaks down polyurethane over time. Worth knowing before you use them near fuelling points.
Dunlop Purofort+ Safety Wellingtons Yellow Steel Toe Cold & Slip Resistant
Which Dunlop welly for which job?
Agriculture and farming
Farming is hard on boots. Slurry, fertilisers, pesticides, and wet mud all attack cheap materials. You need chemical resistance, a steel toe, and grip on slippery yard surfaces.
Look for S5-rated Acifort or Purofort boots. Acifort handles the chemical side well. Purofort is the better pick if you're on your feet all day. Many options in the range come in green — the traditional UK farm boot colour.
Food processing and catering
Food environments have their own rules. Hygiene comes first. Moulded polymer wellies help — made in one piece with no join lines, so there are no crevices for bacteria. Much easier to clean than stitched leather.
Colour matters too. Many food sites use white or blue wellies so contamination shows up on inspection. S4 is the minimum for most food factories. If your site has metal detection gates, look at composite or non-metallic midsole options. Our guide to steel toe vs composite toe safety shoes covers the trade-offs. Browse all safety wellington boots we stock for food-safe options.
Construction sites
S5 is non-negotiable on a construction site. Nails, rebar, metal offcuts — a midsole is not optional. A welly without one won't protect you. Most managed UK construction sites will turn you away without S5 footwear.
Hi-vis matters on busy sites where plant is moving. The Buckbootz BBZ9000 puts you in orange — easy to spot in low light and poor weather. Browse construction safety footwear for the full range of site-ready options.
Buckbootz BBZ9000 Safety Wellington Hi-Viz Orange
Cold storage and freezer work
Cold stores are a specific hazard. You need boots that keep feet warm through a full shift — not just a short walk outside.
The marking to look for is CI. That stands for cold insulation. Standard CI-rated Purofort boots are tested at -20°C. Uninsulated boots conduct cold straight to your feet within minutes at sub-zero temperatures. The Purofort RigPro Fur Lined is built for exactly this — fur-lined and rated to -20°C, in a snug Sneaker Fit last that cuts out heel slippage.
Dunlop Purofort RigPro Safety Boot Fur Lined -20°C
Getting the fit right: sizing and heel slippage
Fit is where buyers go wrong. Heel slippage is the top complaint with work wellies. A loose heel causes blisters, foot fatigue, and poor grip on ladders.
Classic Fit
Most Dunlop wellies use Classic Fit. Buy your normal shoe size. The shape is traditional — wide in the foot, easy to get on and off. If you're between sizes, go up one.
Sneaker Fit (PRO series)
Dunlop's newer PRO series uses a Sneaker Fit last. The heel cup sits snug — much closer to a trainer. Heel slippage goes away. These boots run true to size. If you're switching from an older Classic Fit Purofort, try one size up. The shape is noticeably different.
Sizing tips
- Half sizes aren't available in most welly ranges — size up if you're between sizes.
- Thick socks add bulk. Factor that in for cold store use.
- Feet swell during long shifts. Try boots on at the end of the day if you can.
When a welly is the wrong boot for the job
A work welly does well in wet, muddy, or chemically-hazardous conditions. There are jobs where a different boot serves you better.
Rough, uneven terrain: Scrambling over rubble, rock, or steep ground needs ankle support. A welly shaft is too flexible for that. A rigger boot with a proper ankle cuff is the better call. Read our guide to rigger boots for more.
All-day dry indoor work: Wellies don't breathe. An 8-hour shift in a warm warehouse will leave your feet hot and damp. A breathable safety boot or trainer does the job better in dry indoor environments.
Metal detection gates: Steel toe and steel midsole wellies set off ferrous detectors. Composite or non-metallic safety footwear won't. Our guide to steel toe vs composite toe safety shoes explains which option suits your site.
Frequently asked questions
What is the difference between S4 and S5 safety wellies?
Both are Class II polymer boots with a steel toe cap. S4 gives you 200-joule toe protection, antistatic properties, energy absorption at the heel, and fuel oil resistance. S5 adds a penetration-resistant midsole — a steel plate that stops nails and sharp objects going through the sole — plus a cleated outsole. If there's any chance of sharp debris underfoot, choose S5.
Do I legally have to wear safety wellington boots at work?
Your employer must provide suitable safety footwear under the Personal Protective Equipment at Work Regulations 1992, where a risk assessment identifies the need. If your employer provides safety wellies, you must wear them. If you're self-employed, the duty to assess and equip yourself falls on you.
Are Dunlop Purofort boots worth the extra cost over PVC?
For short or occasional jobs, a PVC boot does the job. For all-day wear, Purofort is a different level. Up to 35% lighter than PVC, thermally insulating, and more flexible — so your feet are less tired at the end of a shift. Purofort lasts longer than basic PVC too. Keep it away from diesel and fuel to get the most out of it. If you're on your feet most of the day, the extra cost pays for itself.
What size should I buy in Dunlop wellies?
For Classic Fit Dunlop boots, buy your normal shoe size. If you're between sizes, go one size up. For the newer Sneaker Fit PRO series, buy true to size — but if you're switching from a Classic Fit Purofort, try one size up. The last shape is closer fitting. Half sizes aren't available, so when in doubt, size up.
Can I use regular wellies on a construction site?
No. Construction sites require S5-rated safety footwear — steel toe cap and a penetration-resistant midsole. Non-safety wellies have neither. Most managed UK construction sites will turn you away without compliant footwear, and you'd have no protection against nails, rebar, and sharp debris underfoot.
What safety wellies do I need for food processing?
S4 is the minimum for most food factory environments. Look for moulded one-piece construction — no join lines means nowhere for bacteria to build up, and easier to clean. White or blue colours are common on food sites so contamination shows up clearly. If your site uses metal detection, ask about composite or non-metallic options to avoid triggering the gates.
What does S5 CI SR mean on a safety welly?
S5 is the safety level: steel toe, antistatic, heel absorption, fuel oil resistance, penetration-resistant midsole, and cleated outsole. CI means cold insulation — the boot is tested to keep feet warm at low temperatures, typically down to -20°C. SR is the current slip resistance marking under EN ISO 20345:2022, tested on a ceramic tile floor with glycerine. Older boots may still show SRC — these remain valid until their certificate expires, no later than November 2029.
Browse the full range of Dunlop wellington boots or explore all safety wellington boots across every brand we stock.