Thursday 27th November, 2025
7-10 minute read
Why the updated standard matters
Workplace safety is constantly evolving, and footwear is one of the most critical aspects of protecting workers. The revised EN ISO 20345:2022 standard introduces clearer rules, more vigorous testing, and improved protection for UK workers exposed to a wide range of hazards.
Foot injuries remain a serious concern. The Health and Safety Executive reports that slips, trips, and falls account for more than one-third of non-fatal injuries in UK workplaces each year. Construction alone recorded over 5,000 non-fatal foot and ankle injuries last year, many linked to poor traction or waterlogged footwear. In environments with sharp materials, uneven surfaces, and unpredictable weather, the correct boots are not just protective, they can be the difference between a safe day on site and a serious injury.
The updated standard replaces EN ISO 20345:2011 and addresses key shortcomings, particularly around waterproofing, slip resistance, and puncture protection. Many older boots labelled WRU (“water-resistant upper”) often failed in real-world conditions, allowing water to enter through seams or tongues.
The new standard replaces WRU with clearer labels: WPA for upper water penetration/absorption resistance and WR for full footwear waterproofing. WR certification ensures the whole boot has been tested for water ingress under controlled conditions. It is important to note that while WR boots are designed to be fully waterproof when new, performance may decrease over time due to wear, repeated use, or exposure to chemicals or abrasive environments.
EN ISO 20345:2022 Footwear Classes with Requirements
| Class | Toe Protection | Water Resistance | Puncture Protection | Slip Test | Energy Absorption | Fuel/Oil Resistance | Notes |
| S1 | ✓ | ✗ | Optional (P/PL/PS) | Baseline a must | ✓ | FO | Indoor/low moisture |
| S2 | ✓ | WPA | Optional | Baseline | ✓ | FO | Water-repellent upper |
| S3 | ✓ | WPA | Mandatory | Baseline | ✓ | FO | Outdoor / construction |
| S6 | ✓ | WR | Optional | Baseline | ✓ | FO | “S2 + WR” waterproof |
| S7 | ✓ | WR | Mandatory | Baseline | ✓ | FO | “S3 + WR” waterproof |
Slip Resistance and Puncture Protection
Slip resistance is mandatory for all footwear certified under EN ISO 20345:2022. Every boot must pass a baseline slip test on a ceramic tile with a detergent solution to ensure reliable grip on wet or slippery surfaces. Additional markings, such as SR, indicate performance under more extreme conditions, including glycerine on ceramic tiles. Slip-resistant footwear is critical in the UK, where slips alone cause over 30,000 workplace injuries annually. High-risk sectors include construction, logistics, manufacturing, and environmental services, where wet or uneven surfaces are common.
Puncture resistance has also been clarified and refined. Boots with metallic midsoles retain the P marking, while non-metal midsoles are labelled PL (tested with a 4.5 mm nail) or PS (tested with a 3.0 mm nail), depending on the risk level. This ensures that procurement teams can select footwear that matches real-world hazards, such as exposed nails, sharp debris, and uneven terrain. These new labelling conventions provide far greater transparency than the previous single “P” marking, giving employers confidence in their specifications.
Footwear Markings Explained
| Marking | Meaning | What It Protects Against |
| WR | Whole-footwear waterproofing | Sustained water exposure |
| WPA | Water penetration/absorption upper | Heavy splashes / wet working conditions |
| P | Steel anti-penetration | ≥1100 N penetration force |
| PL | Textile anti-penetration (4.5 mm nail) | Lighter, flexible puncture resistance |
| PS | Textile anti-penetration (3.0 mm nail) | Stricter nail test, stronger barrier |
| SR | Optional enhanced slip resistance | Ceramic tile + glycerine tests |
| FO | Fuel and oil resistant outsole | Oils, hydrocarbons |
| SC | Scuff-cap abrasion resistance | Toe abrasion on rough surfaces |
| LG | Ladder-Grip | Stability on rung ladders |
Understanding S-Classifications and the role of S6 and S7
EN ISO 20345:2022 classifies footwear according to protection levels:
- SB – Basic toe protection (200 J toe cap).
- S1 – SB + anti-static properties and energy absorption in the heel.
- S2 – S1 + upper water resistance (WPA).
- S3 – S2 + puncture-resistant midsole and cleated outsole.
- S4/S5 – Polymer boots, often used in wet or chemical environments, with S5 adding puncture resistance.
The new classifications, S6 and S7, redefine waterproof and high-protection footwear:
- S6 – Builds on S2 and adds full footwear waterproofing (WR). Ideal for roles involving prolonged water exposure, such as drainage, utilities, cleaning, highway maintenance, and landscaping. S6 boots are also suitable for workers who spend long periods standing in wet environments, reducing the risk of foot fatigue and cold-related injuries.
- S7 – Builds on S3 and adds full WR waterproofing. This is the highest level of protection for leather and upper-material footwear, combining puncture resistance, slip resistance, and waterproofing. S7 is ideal for construction, civil engineering, rail infrastructure, groundworks, and other demanding outdoor environments where multiple hazards such as water, uneven surfaces, and sharp objects coexist. S7 replaces the older “S3 + WR” approach with stricter, more reliable testing.
By adopting S6 or S7 footwear, employers provide a tangible safety upgrade, helping reduce the risk of slips, puncture injuries, and water-related discomfort or fatigue. In sectors like construction, where workers often spend hours outdoors on wet or uneven terrain, this can significantly improve daily safety outcomes.
Choosing Between S3, S6 and S7
| Feature | S3 | S6 | S7 |
| Waterproof | No (WPA only) | Yes (WR) | Yes (WR) |
| Puncture Protection | Yes | Optional | Yes |
| Muddy/Outdoor Sites | Good | Better | Best |
| Long-Term Wet Conditions | Moderate | High | Highest |
| Heavily Contaminated Surfaces | Good | Excellent | Excellent |
Why these changes are important for UK workers
The introduction of S6 and S7 is more than just technical, it directly benefits workers’ wellbeing and performance. Tens of thousands of foot injuries occur in the UK each year, many exacerbated by wet conditions, sharp objects, or inadequate traction. WR-certified footwear keeps feet dry and protected, improving comfort and focus, which in turn reduces fatigue and the likelihood of accidents. Accurate labelling also helps procurement teams specify footwear correctly for different roles, ensuring that workers in high-risk environments get the protection they need.
The clarity of the new standard also aids training and compliance. Workers can understand exactly which features their boots provide, and employers can easily justify footwear choices in risk assessments, meeting both health and safety requirements and insurance expectations.
Supporting businesses through the transition
Employers now need to review risk assessments and update footwear specifications to align with EN ISO 20345:2022. Roles that previously relied on S3 boots may now benefit from S7, while S6 can replace older WRU-labelled footwear for indoor or light outdoor tasks. Stronghold Global supports organisations across the UK in transitioning to the new standard, helping businesses balance compliance, safety, and comfort.
The updated EN ISO 20345:2022 standard is not simply a technical update. It represents a meaningful improvement in worker protection, combining stronger waterproofing, slip resistance, and puncture protection. S7 footwear now represents the clearest indicator of maximum protection for industries where outdoor hazards, wet conditions, and sharp surfaces are common. Adopting S6 or S7 boots demonstrates a proactive approach to workplace safety, showing commitment to employee wellbeing and operational reliability.
