Safety boot ratings are the codes such as SB, S1, S1P, S2 and S3 printed on the label or tongue of safety footwear. They come from the standard EN ISO 20345 and tell you exactly what protection each boot or shoe offers, from the toe cap up to water and puncture resistance.

The current version is EN ISO 20345:2022. Footwear certified to the older 2011 version stays valid until its certificate expires, so you'll see both sets of markings on the shelves for a while yet.

What do SB, S1, S2 and S3 mean?

Each rating builds on the one before it. SB (Safety Basic) is the entry level: every SB shoe has a protective toe cap tested to withstand a 200 joule impact, roughly a 20 kg weight dropped from one metre.

S3 remains the most popular all-round rating for site work. S6 and S7 are new in the 2022 standard.

What changed for S1P under EN ISO 20345:2022?

S1P has traditionally meant S1 plus a penetration-resistant midsole, protecting against nails, screws and sharp debris underfoot. Under the 2022 standard, the letters after the rating tell you which type of midsole is fitted:

• P now means a metal midsole only, so S1P indicates a steel plate.
• PL is a non-metallic midsole tested with a 4.5 mm nail, giving codes such as S1PL.
• PS is a non-metallic midsole tested with a thinner 3 mm nail, giving codes such as S1PS and S3S.

Non-metallic midsoles are lighter and more flexible. Because the tests differ, check which type your risk assessment calls for if thin, sharp objects such as screws or wire are common on site.

Slip, fuel and other markings

You may also see SRA, SRB or SRC markings. These are 2011-era codes that buyers will still find on older stock. SRC, for example, confirms the sole passed slip-resistance tests on both ceramic and steel surfaces.

Under the 2022 standard, all safety footwear must pass a slip test on ceramic tile with a soap solution, and this carries no separate marking. The optional SR marking means the footwear has also passed a ceramic test with glycerine, which better reflects oily or greasy floors.

Other optional codes are worth knowing. FO means fuel and oil resistance, which is no longer mandatory from S1 upwards, so look for it if you work around diesel or oils. Antistatic properties are built into S1 and above. For wet and muddy work, all-rubber or polymer footwear such as safety wellingtons carries its own S4 and S5 ratings.

How to choose the right safety boot rating

Choosing the right S code means assessing your workplace hazards. Is it wet or dry, indoors or out, is there a puncture risk, and what is the floor surface like?

• Dry, indoor and smooth floors: S1 or S1P footwear, including lightweight safety trainers.
• Outdoors or damp: S2 at minimum, or S3 if there's debris underfoot.
• Building sites: S3 safety boots with ankle support are the usual baseline, but site rules can go further.
• Greasy or oily floors: look for the SR marking and, where relevant, FO.

Don't assume a higher number is always better: S3 boots are often heavier and stiffer than S1P. For more on slip codes, see our guide to slip-resistant footwear ratings.

Quick answers

What is the difference between S1P and S3 safety boots?

Both have a toe cap and a penetration-resistant midsole. S3 adds water-resistant uppers and a cleated outsole, so it suits outdoor and wet sites, while S1P suits dry indoor work.

Are safety boots certified to EN ISO 20345:2011 still valid?

Yes. Footwear certified to the 2011 version remains valid until its certificate expires, so older markings such as SRC will be around for some time.

What does SR mean on safety shoes?

Under EN ISO 20345:2022, SR means the footwear has passed an additional slip test on ceramic tile with glycerine, on top of the mandatory soap solution test that all safety footwear must pass.

Match the code to the conditions and you'll stay safe, comfortable and compliant. Explore our full safety footwear range, or contact us if you'd like help reading a label.