Confused by safety boot ratings like S1, S1P, S2 and S3? You're not alone. Understanding these codes is essential for choosing footwear that meets your workplace requirements and keeps you protected. This guide breaks down everything you need to know about EN ISO 20345 safety standards.
What is EN ISO 20345?
EN ISO 20345 is the European safety standard that defines requirements for safety footwear. The "EN" stands for European Norm, while "ISO" indicates it aligns with international standards. Any boot or shoe carrying this certification has been tested and approved for workplace protection.
All footwear certified to EN ISO 20345 must include a protective toecap capable of withstanding an impact of 200 joules—roughly equivalent to a 20kg weight dropped from a metre height. This baseline protection is then enhanced with additional features depending on the specific rating.
Understanding Safety Boot Ratings
Safety ratings are indicated by letters and numbers following the "S" prefix. Each rating builds upon the previous one, adding more protective features. Here's what each rating means:
Quick Comparison: Safety Boot Ratings at a Glance
| Rating | Water Resistant | Midsole Protection | Best For |
|---|---|---|---|
| SB | No | No | Basic indoor work |
| S1 | No | No | Dry indoor environments |
| S1P | No | Yes | Indoor construction/workshops |
| S2 | Yes | No | Outdoor work, light rain |
| S3 | Yes | Yes | Construction sites, warehouses |
| S4 | Waterproof | No | Standing water environments |
| S5 | Waterproof | Yes | Farming, food processing |
Which Safety Rating Do You Need?
Choosing the right safety rating depends on your specific workplace hazards. Here are some general guidelines:
For Office and Warehouse Work
If you work primarily indoors on dry floors with minimal risk of stepping on sharp objects, S1 rated footwear provides adequate protection while remaining comfortable for all-day wear.
For Construction and Building Sites
S3 rated boots are typically mandatory on UK construction sites. They offer protection against water, sharp objects underfoot, and provide superior grip on uneven terrain. When in doubt, S3 is the safest choice for trade work.
For Electrical Work
Electricians should look for S1P or S3 boots with composite (non-metallic) toecaps and midsoles. Metal components can conduct electricity, so composite options provide necessary protection without the electrical risk.
For Agriculture and Food Processing
S4 or S5 wellingtons are essential when working in wet environments or where hygiene standards require easily washable footwear.
Steel Toe vs Composite Toe: Which is Better?
Both steel and composite toecaps meet EN ISO 20345 protection standards. The choice comes down to your specific needs:
Steel toecaps are thinner, allowing for sleeker designs. They're extremely durable and typically more affordable. However, they conduct cold and heat, and will trigger metal detectors.
Composite toecaps (made from fibreglass, carbon fibre or Kevlar) are lighter, don't conduct temperature extremes, and won't set off metal detectors. They're ideal for electricians, airport workers, and those who prefer lighter footwear.
Browse our full range of safety boots and safety trainers to find your perfect fit.
Frequently Asked Questions
What does S3 mean on safety boots?
S3 indicates the boot meets EN ISO 20345 standards with a protective toecap, water-resistant upper, penetration-resistant midsole, energy-absorbing heel, antistatic properties, and a cleated outsole. It's the most versatile rating for construction and outdoor work.
Is S1P better than S3?
Neither is inherently "better"—they serve different purposes. S1P boots have midsole protection but lack water resistance, making them ideal for dry indoor environments. S3 boots add water resistance and cleated soles, making them better for outdoor and wet conditions.
How long do safety boots last?
With daily use, quality safety boots typically last 6-12 months. Signs you need replacements include worn soles, damaged toecaps, deteriorating stitching, or compressed cushioning that no longer provides support.
Are safety trainers as protective as boots?
Safety trainers with the same rating (e.g., S3) offer identical protection levels to boots. The difference lies in ankle support and coverage—boots provide more stability on rough terrain, while trainers offer greater flexibility and comfort.
At STB, we stock a comprehensive range of safety footwear across all ratings from trusted brands including Amblers Safety, DeWalt, CAT, and Skechers Work. Need help choosing? Our team is here to assist—contact us for expert advice.