Safety Footwear Standards Explained: S1, S3 & S7 – Which Do You Need?
Why Safety Footwear Standards Matter
Safety footwear in the UK and EU is governed by EN ISO 20345:2022, the international standard that defines the minimum protection requirements for occupational safety boots and shoes. Every pair of certified safety footwear carries a designation — S1, S1P, S2, S3, S5, or S7 — that tells you exactly what protection it provides.
Choosing the wrong rating can leave workers exposed to hazards, and in many industries it's a legal requirement under the Personal Protective Equipment at Work Regulations 2022 to provide appropriate footwear. Here's what each rating means.
The Baseline: What All Safety Footwear Must Include
Under EN ISO 20345, all certified safety footwear must include a 200-joule toecap — capable of withstanding a 200J impact and 15kN compression. This is the minimum requirement regardless of the S-rating. Beyond this, each designation adds further protections.
Safety Footwear Ratings Explained
S1 – Basic Protection, Dry Conditions
Includes: 200J toecap, antistatic properties, energy absorption in the heel, fuel oil resistance on the outsole.
S1 is suitable for light industrial environments where the ground is dry and relatively clean. It does not include a midsole for puncture protection or water resistance.
Typical users: Light manufacturing, indoor warehousing, retail stockrooms.
S1P – S1 + Puncture-Resistant Midsole
Includes: Everything in S1, plus a penetration-resistant midsole (minimum 1,100N).
S1P is one of the most common ratings on UK construction sites. The midsole protects against nails and sharp objects underfoot — a critical addition for any site where debris is present.
Typical users: Construction, carpentry, general contracting, light groundworks.
S2 – S1 + Water Resistance
Includes: Everything in S1, plus water-resistant upper (tested to 60 minutes).
S2 adds water resistance but no midsole puncture protection. It's less common than S1P or S3 but suits environments that are damp rather than muddy or debris-strewn.
S3 – The Most Common Outdoor Standard
Includes: Everything in S2 (water resistance) plus a penetration-resistant midsole. Also typically includes a cleated outsole for grip on uneven terrain.
S3 is the go-to rating for most outdoor trades in the UK. It combines water resistance with puncture protection — making it suitable for the vast majority of construction, utilities, and groundworks environments.
Typical users: Construction workers, groundworkers, landscapers, utilities engineers, roofers, plant operators.
If in doubt, S3 is the safe default for any outdoor or mixed-environment role.
S5 – S3 + Waterproof Boot (Wellington Style)
Includes: All S3 protections in a full waterproof boot construction (typically a rubber or PU wellington-style boot).
S5 is designed for environments with standing water, mud, or chemical splash risk. Common in agriculture, drainage, and civil engineering.
Typical users: Agricultural workers, drainage engineers, civil groundworks in wet conditions.
S7 – The New High-Performance Standard
Includes: All S3 protections plus a fully waterproof boot construction tested to a higher standard than S5, with improved durability and comfort requirements introduced in the 2022 revision of EN ISO 20345.
S7 is the modern replacement for S5 in many applications and is increasingly specified by larger contractors and public sector employers. It offers the highest level of protection in the standard EN ISO 20345 framework.
Typical users: Highways maintenance, civil engineering, utilities, any role requiring maximum waterproofing and durability.
Additional Markings to Look For
Beyond the S-rating, safety footwear labels may carry additional codes:
- A – Antistatic (all S-rated boots include this by default)
- E – Energy absorption in heel
- WR – Water-resistant upper
- WRU – Water-resistant upper (upper only, not sole)
- CI – Cold insulation (suitable for cold storage environments)
- HI – Heat insulation (suitable for hot surfaces)
- HRO – Heat-resistant outsole (contact with hot surfaces up to 300°C)
- SRC – Highest slip resistance rating (tested on ceramic tile and steel)
For most UK trades, look for S3 SRC as a minimum — it covers the most common hazards and provides certified slip resistance.
Quick Reference: Which Standard Do You Need?
- Indoor, dry, light industrial: S1 or S1P
- Construction, general site work: S1P or S3
- Outdoor, wet or muddy conditions: S3
- Standing water, agriculture, drainage: S5 or S7
- Highways, civil engineering, maximum protection: S7
Do Safety Boots Expire?
Safety footwear doesn't have a fixed expiry date, but most manufacturers recommend replacing boots every 12–18 months with regular use, or sooner if the sole, toecap, or upper shows visible wear or damage. Degraded footwear may no longer meet the standard it was certified to — and worn soles significantly reduce slip resistance.
Shop Safety Footwear at ProAttire
We stock a range of EN ISO 20345 certified safety boots and shoes across S1P, S3, and S7 ratings — suitable for construction, utilities, logistics, and more. All footwear is available for individual purchase or bulk orders for teams.
Browse our full safety footwear range →
Need help specifying the right footwear for your workforce? Contact our team — we work with businesses across Preston, Lancashire and the UK to kit out their teams correctly.
While you're here, explore our full workwear range: