WORK GEAR

Safety Boot Ratings Explained: EN ISO 20345 Codes Guide

Learn what safety boot ratings mean, including SB, S1, S2, S3, S4 and S5 codes, slip resistance markings and EN ISO 20345 standards.


Safety Boot Ratings Explained: EN ISO 20345 Codes Guide

Safety boot ratings can be confusing, especially when product labels include codes such as SB, S1, S2, S3, S4, S5, SRC, WR, HRO or CI. Each code tells you something important about the protection the footwear provides, from toe protection and slip resistance to water resistance, penetration protection and heat-resistant soles.

Choosing the right safety boots is not just about comfort or style. The rating should match the risks of the job, whether you work indoors, outdoors, around sharp objects, on wet floors, in cold conditions or on demanding construction and industrial sites.

In this guide, we explain the main safety boot ratings, what the common footwear codes mean, and how to choose the right safety boots or safety shoes for your working environment.

What Do Safety Boot Ratings Mean?

Safety boot ratings are codes that show what protection a boot or shoe offers. Common ratings include SB, S1, S2, S3, S4 and S5, with each code covering features such as toe protection, antistatic properties, water resistance, penetration resistance and outsole grip.

The right rating depends on the job. For example, indoor work may only need a lighter safety shoe, while outdoor, wet or high-risk environments may require stronger protection such as S3, S4 or S5 footwear.

Safety Boot Ratings Explained

Safety boot ratings help show what level of protection a boot or shoe provides. The main ratings include SB, S1, S2, S3, S4 and S5, with each one adding different protective features.


SB Safety Boots

SB stands for Safety Basic. This is the minimum safety footwear rating and includes toe protection against impact and compression.

SB footwear may also include extra features, shown with additional letters. For example, SB-P means the footwear also includes penetration-resistant midsole protection.

An example to consider is the Click Goodyear Welt Boots, which offer safety toe protection with additional protective features.

SB Safety Boots

S1 Safety Boots

S1 Safety Boots

S1 safety boots include the basic toe protection of SB, plus extra features such as antistatic properties, energy absorption in the heel, fuel oil resistance and a closed heel area.

S1 footwear is usually suited to dry indoor environments where toe protection is needed, but water resistance is not a major requirement.

You may also see S1P, which means the footwear includes S1 protection plus penetration-resistant midsole protection.

An example to consider is the Click Steel Toe Cap Rigger Boots, which are a practical option for users who need toe protection and underfoot penetration resistance.


S2 Safety Boots

S2 safety boots include the same protection as S1, with added resistance to water penetration and absorption through the upper. This makes S2 footwear more suitable for work where occasional moisture or outdoor exposure is expected, but where midsole penetration protection is not required.

S3 Safety Boots

S3 Safety Boots

S3 safety boots include the protection of S2, with added penetration-resistant midsole protection and a cleated outsole.

This makes S3 one of the most common ratings for construction, warehouse, site and outdoor work, especially where there may be nails, sharp objects, uneven ground or wet conditions.

Examples to consider include Click Steel Toe Safety Shoes and Click Lightweight Composite Toe Safety Trainers, which are both designed for S3-rated protection.


S4 Safety Boots

S4 safety boots are usually made from all-rubber or all-polymeric materials. They include toe protection, antistatic properties, fuel oil resistance, heel energy absorption and waterproofness.

S4 footwear is commonly used in wet, washdown or hygiene-focused environments where a waterproof safety boot is needed.

An example to consider is the Dunlop FoodPro Purofort Multigrip Safety Boots, which are designed for S4-rated protection.

S4 Safety Boots

S5 Safety Boots

S5 Safety Boots
S5 safety boots include the protection of S4, with added penetration-resistant midsole protection and a cleated outsole. This makes S5 footwear suitable for demanding wet, muddy, cold or outdoor environments where waterproofness, grip and underfoot protection are important. Examples to consider include Dunlop Purofort PLUS Boots and Dunlop Purofort Thermo+ Full Safety Boots, which are designed for S5-rated protection.

EN ISO 20345:2011 vs EN ISO 20345:2022

Some safety footwear may still show EN ISO 20345:2011, while newer products may be marked to EN ISO 20345:2022. Both refer to safety footwear standards, but the 2022 version introduced updated classifications and markings.

For most buyers, the main ratings such as SB, S1, S2, S3, S4 and S5 are still important to understand. However, newer markings such as S6, S7 and SR may also appear on product labels or technical data sheets.

This is why it is always worth checking the full product specification, not just the main rating code. The standard, rating and extra abbreviations together give a clearer picture of what the boot or shoe is designed to protect against.


Slip Resistance Ratings: SRA, SRB, SRC and SR

Slip resistance is another important marking to check when choosing safety footwear, especially for wet, oily, smooth or high-traffic working areas. Under older EN ISO 20345:2011 markings, you may see SRA, SRB or SRC:
  • SRA means the footwear was tested on ceramic tile with a diluted soap solution.
  • SRB means the footwear was tested on steel with glycerol.
  • SRC means the footwear passed both SRA and SRB tests.
Under the newer EN ISO 20345:2022 standard, the old SRA, SRB and SRC markings are no longer used in the same way. Slip resistance is now part of the basic requirement, while SR may appear as an additional slip resistance marking. For buyers, the key point is simple: always check the full product specification, especially if slip resistance is important for the working environment.

Common Safety Footwear Codes to Know

Safety boots may also include extra codes alongside the main rating. These codes show additional protection features that may be important for certain jobs or working environments.

  • P means penetration-resistant midsole protection, helping protect the underfoot from sharp objects.
  • SRC is an older slip resistance marking, showing the footwear passed both SRA and SRB slip resistance tests.
  • SR is used under newer markings for additional slip resistance testing.
  • CI means cold insulation, useful for cold stores, outdoor work and low-temperature environments.
  • CR means cut-resistant upper, adding protection against cutting hazards.
  • HRO means heat-resistant outsole, useful where soles may contact hot surfaces.
  • WR means water resistance of the whole footwear.
  • FO means fuel oil resistance of the outsole.

For example, a boot marked S5 CI CR SRC offers S5-rated protection, plus cold insulation, cut-resistant upper protection and older SRC slip resistance.

Always check the full product specification, as the main safety rating and extra codes together give the clearest picture of what the footwear is designed for.


Which Safety Boot Rating Do You Need?

The right safety boot rating depends on the hazards in your working environment. Use this as a quick guide before checking the full product specification.

Work Environment Rating to Consider Why
Dry indoor work S1 Suitable where toe protection and basic workplace protection are needed, but water resistance is not a major concern
Warehouses, site work and general trade use S3 Adds water-resistant upper protection, penetration resistance and a cleated outsole
Wet or washdown environments S4 Designed for waterproof all-rubber or all-polymeric footwear
Outdoor, muddy or demanding site conditions S5 Adds underfoot penetration resistance and cleated outsole protection to waterproof safety footwear
Cold stores or low-temperature work CI marking Look for cold insulation alongside the main safety rating
Work around hot surfaces HRO marking Look for a heat-resistant outsole if the sole may contact hot surfaces

Always check the full product details before buying, as the main rating and extra codes together show what the footwear is designed for.


Choosing Safety Boots at MTN SHOP

Choosing the right safety boots starts with matching the rating to the job. For general site and warehouse work, S3 safety boots or shoes are often a practical choice because they include toe protection, penetration resistance, water-resistant upper protection and a cleated outsole.

For wet, muddy, washdown or cold environments, S4 or S5 safety wellingtons may be more suitable, especially where waterproofness, grip and underfoot protection are important.

Browse our safety boots and safety shoes collections to compare different ratings, styles and features.

Frequently Asked Questions


Safety boot ratings are codes that show what level of protection a boot or shoe provides. Common ratings include SB, S1, S2, S3, S4 and S5, with each rating covering different features such as toe protection, water resistance, penetration resistance and outsole grip.
S1 safety boots are usually suited to dry indoor work and include features such as toe protection, antistatic properties, heel energy absorption and a closed heel area. S3 safety boots add water-resistant upper protection, penetration-resistant midsole protection and a cleated outsole, making them more suitable for outdoor, site and construction work.
S3 safety boots include resistance to water penetration and absorption through the upper, but this does not always mean the whole boot is fully waterproof. For full waterproof footwear, check the product specification and look for markings such as WR or consider suitable S4 or S5 safety wellingtons.
SRC is an older slip resistance marking used under EN ISO 20345:2011. It means the footwear passed both SRA and SRB slip resistance tests. Under newer markings, you may see SR instead for additional slip resistance testing.
Composite toe caps and steel toe caps can both meet the required toe protection standards for safety footwear. Steel toe caps are strong and widely used, while composite toe caps are often lighter and metal-free. The right choice depends on the job, comfort needs and any site-specific requirements.

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