Helly Hansen Work Trousers: The Complete Guide for UK Tradespeople

Helly Hansen has been making technical workwear since 1877, and its work trousers are among the most recognisable on UK building sites. If you are looking at the Alna 2.0 range or Chelsea Evolution and trying to figure out which model fits your role, this guide breaks down the full trouser collection, explains the European sizing system, and compares HH against the other premium brands.

Why Trades Choose Helly Hansen Work Trousers

The brand's workwear appeal comes down to three things: stretch fabrics that move with you, hi-vis options built for construction and rail standards, and a Scandinavian heritage that takes cold and wet weather seriously.

Most key HH trouser lines use four-way stretch construction, which matters on a working day that involves climbing, kneeling, and getting in and out of vehicles. Reinforced knee areas and knee pad pockets are standard across the range, and fabric weights are chosen for site durability rather than lightness. These are not cheap trousers and they are not trying to be - the price reflects a longer working life and features that cheaper alternatives cut.

The range splits into three main categories: hi-vis construction trousers (the Alna 2.0 family), non-hi-vis work trousers (Chelsea Evolution and ICU), and waterproof outer layers for sustained wet conditions. Baselayer thermals sit underneath all of it for winter work.

The Alna 2.0 Range - Hi-Vis Construction

The Alna 2.0 is Helly Hansen's core hi-vis construction trouser and the model most commonly seen on UK sites. Four main variants cover the standard requirements.

Alna 2.0 Hi Vis Work Trouser Class 1 (77420, £75) - EN ISO 20471 Class 1 hi-vis with stretch fabric and standard knee pad pockets. Suited to environments where visibility is required but Class 2 is not mandated.

Alna 2.0 Stretch Hi Vis Work Pant Class 2 (77421, £80) - Steps up to Class 2 hi-vis with additional reflective banding. Highways, utilities, and rail environments that specify Class 2 as a minimum will need this or one of the construction variants.

Alna 2.0 Construction Stretch Trouser Class 1 (77422, £85) - Adds construction-specific reinforcement at high-wear points and additional pocket options over the standard Alna 2.0. Class 1 visibility.

Alna 2.0 Construction Stretch Trouser Class 2 (77423, £85) - Same construction-spec reinforcement as the 77422 but at Class 2 visibility. Both sit at the same price, so if your environment accepts either Class, the 77423 gives more coverage for no extra cost.

All four Alna 2.0 variants share the same four-way stretch panel construction, knee pad compatibility, and reinforced hem. The differences come down to hi-vis class and whether the construction-spec reinforcement is needed for your role.

Chelsea Evolution - The Non-Hi-Vis Performer

The Chelsea Evolution range is Helly Hansen's answer to the Snickers 6241 and Blaklader 1459 for tradespeople who do not need hi-vis certification but want quality stretch work trousers.

Chelsea Evolution Stretch Construction Trouser (77441, £105) - Four-way stretch panels, multiple tool pockets, knee pad pockets, and a reinforced seat. The main Chelsea Evolution model. Construction and renovation tradespeople who work indoors or on private sites without a hi-vis requirement will find this covers most needs.

Chelsea Evolution 4-Way Stretch Work Pant (77446, £100) - A slightly lighter variant of the same family at £100. Marginally fewer reinforcement layers and a cleaner silhouette - useful for trades that want the stretch and pocket layout without the full construction spec. Available in black and navy.

Both Chelsea Evolution models use the same European numeric sizing as the rest of the HH range. If you are comparing against Snickers 6241 on price, the Chelsea Evolution 77441 sits a little above at £105 but carries comparable stretch quality and pocketing.

ICU - The Premium Stretch Trouser

ICU Stretch Work Trouser with Holster Pockets (77471, £130) - Sits at the top of the HH stretch trouser range. The ICU adds holster-style side pockets that hang lower on the thigh than standard patch pockets, making it the preferred option for electricians and carpenters who need frequent access to tools without crouching to a knee-level pocket. Hi-vis Class 1 rated, it crosses the line between a non-hi-vis construction trouser and a visible outer layer, which suits roles that move between indoor and site environments in the same day.

Waterproof Options

Helly Hansen offers several waterproof lower-body options that differ significantly in their construction and intended use.

Alta Rain Pant Class 2 (70460, £50) - A lightweight hi-vis waterproof overtrouser designed to go over your work trousers when it rains. At £50 this is a throw-on weather layer, not a primary workwear garment. Good for unpredictable conditions but not designed for sustained outdoor work in heavy rain.

Alna 2.0 Shell Bib and Brace Pant Class 2 (71493, £170) - A full waterproof bib and brace for wearing over a baselayer or mid-layer in sustained wet conditions. Groundwork, utilities, and rain-exposed construction roles where an overtrouser would soak through at the joins.

Alna 2.0 Winter Waterproof Padded Salopette Class 1 (71490, £150) - Adds insulation for cold weather over the waterproof shell. Class 1 visibility.

Alna 2.0 Winter Construction Salopette Class 2 (71491, £175) - The full winter outer layer: insulated, waterproof, and Class 2 hi-vis. This is the garment for groundwork, civils, and outdoor trades working through a UK winter. It is the most expensive item in the collection and the most capable in extreme conditions.

Baselayer Thermals

Three HH baselayer bottoms complete the layering system for cold-weather work.

Lifa Pant Long Johns (75505, £27) - HH's standard thermal baselayer using polypropylene Lifa fabric. Moves moisture away from the skin and dries quickly. The practical choice for most outdoor workers who need a thermal layer under their site trousers.

Lifa Merino Long Johns (75506, £59) - Upgrades the synthetic Lifa to a merino wool blend, adding natural temperature regulation and odour resistance. Worth the extra cost over the standard Lifa if you find synthetic thermals uncomfortable on long shifts or wear the same base layer across multiple days.

FRAS Flame Retardant Anti-Static Fakse Baselayer Pant (75475, £55) - For environments where the baselayer itself needs FR and anti-static certification - oil and gas, petrochemical, or arc flash risk environments. A specialist item: only select this when your risk assessment specifies certified FR layers under your primary garment.

Helly Hansen Sizing Explained

HH work trousers do not use standard UK trouser sizing. They use European numeric sizing available in two leg lengths - Regular and Short.

Regular sizing runs from 44 to 62, with the number roughly equating to the waist measurement in centimetres. Regular 44 fits up to approximately W29 with a 31-inch inside leg. Regular 50 is approximately W34, and Regular 62 reaches W45. Short sizing runs from 92 to 116, offering a 29-inch inside leg for the same waist range.

A rough conversion: take your UK waist in inches and add approximately 25 to get the equivalent HH Regular size. A 34-inch UK waist equates roughly to HH Regular 58-60. If you are between sizes, HH generally recommends sizing up to preserve freedom of movement.

If you are familiar with Snickers or Blaklader sizing - both of which use a similar European numeric approach (C-sizing) - the HH system works on the same principle. The main trap is forgetting that the Short leg is coded in the 90s rather than as a separate letter indicator.

Helly Hansen vs Snickers vs Blaklader

These three brands compete directly at the premium end of the UK work trouser market.

Snickers (particularly the 6241 AllroundWork and 6251 FlexiWork) has the widest model range, a larger knee pad system that many site workers prefer, and is the benchmark most UK tradespeople compare against. HH matches Snickers on stretch quality and typically undercuts it slightly on price at equivalent spec levels.

Blaklader has a similar Nordic construction heritage and overlaps closely with HH on construction and hi-vis products. Blaklader's flagship models (1459, 1860) tend to carry heavier fabric weights. HH generally has the edge on stretch and mobility; Blaklader on outright fabric durability in the highest-abrasion applications.

For hi-vis construction and rail work, the Alna 2.0 range is competitive with anything in either brand's hi-vis lines. For general site work without hi-vis requirements, the Chelsea Evolution sits comfortably alongside Snickers 6241 and Blaklader 1459 as a comparable choice.

Which Trouser for Which Trade

• Construction and groundwork (hi-vis required) - Alna 2.0 Class 2 (77421 or 77423). If your site mandates construction-specific features, 77423. Otherwise 77421 gives the same visibility at £5 less.
• Rail and highways - Alna 2.0 Class 2 minimum. Check whether your contract requires EN ISO 20471 alone or the additional RIS-3279-TOM rail standard - confirm this with your employer before purchasing.
• Electricians and carpenters (no hi-vis requirement) - ICU 77471 for the holster pocket layout, or Chelsea Evolution 77441 if the side pocket format is not a priority.
• General trades and renovation - Chelsea Evolution 77446 (lighter variant) or 77441 (full construction spec). The £5 difference is worth paying for the heavier reinforcement if you are on your knees regularly.
• Winter outdoor work - Alna 2.0 Winter Padded Salopette (71490, Class 1) or 71491 (Class 2) over a Lifa baselayer. The Alta Rain Pant (70460, £50) handles milder wet days as a lighter alternative.
• FR and hazardous environments - The FRAS baselayer pant (75475) as an underlayer where certified FR is required. For primary FR outer trousers, check the broader Helly Hansen FR range separately as the trousers in the main work trouser collection do not carry primary FR ratings.

See the full Helly Hansen work trousers collection, or browse all work trousers across brands. The full Helly Hansen range including jackets, thermals, and accessories is also worth a look.