What's The Meaning Of Each Safety Footwear Code?

SRC, O4, or S5. These are some of the codes that often appear when you're looking for footwear. But what does it mean? Is it important? How can this determine which footwear is better suited for you?

These are some of the questions that we'll be answering in this video. We'll also provide you a list of safety codes and their respective meanings. This way, you'll know if you're buying the right footwear for you.

First, what you need to know is that these codes represent the safety level of the footwear. They ensure the user that the footwear complies with all the requirements to provide the defined safety level.


In the EU internal market, the regulation that defines the legal obligations of PPE is the Regulation (EU) 2016/425 of 9 March 2016 on personal protective equipment. You can easily see if a PPE complies with this regulation through the CE marking.

If a product has this mark, it means that it is approved and it follows all the EU regulations.

EN ISO 20345:2011 & EN ISO 20347:2011

There are two main standards:

  • EN ISO 20345, that refers to the requirements for safety footwear.

  • EN ISO 20347, that refers to the requirements for occupational footwear, for activities that don't expose the user to any mechanical risks, like impacts or compressions.

These standards specify additional basic requirements for safety footwear. You can see if the footwear is complying with these standards by looking at its datasheet or product description.

Códigos de Calçado de Segurança

After learning what each requirement means, it's time to find out the meaning of the specific codes. Each standard has different codes that provide information about the protection level provided by the footwear.

Let’s begin with the codes of EN ISO 20345, which are the codes for safety footwear. This standard divides the footwear into 2 types. The first one includes all the safety footwear, but the ones made with rubber uppers or polymer uppers. The second type includes only footwear made completely with rubber or polymers.

The first type of footwear has four codes: SB, S1, S2, and S3. The second type has two codes besides the SB. Those are the S4 and the S5.


SB stands for Safety Basic, so it’s the lowest safety level of this standard. SB-rated footwear is slip-resistant and has a safety toe cap that protects your feet at 200J impacts.

This code also applies to the second type of footwear.


S1 footwear has all the SB features, has a closed heel area, as well as an energy absorption heel, and is antistatic, and oil-resistant.


Has all the S1 features and prevents water penetration.


Has all the S2 features and also has a midsole penetration resistance (puncture proof), that prevents sharp objects from piercing through the sole and hurting you.


Has all the S1 features, but applied to footwear made with rubber uppers or polymer uppers.


Has all the S4 features and a midsole penetration resistance.

The following codes are the EN ISO 20347, which means they’re the occupational footwear codes. Once again, these codes are divided into the same two types of footwear.

The first type subdivides into 4 codes: OB, O1, O2, and O3. And the second type into OB as well, O4 and O5.


OB footwear meets the basic requirements, which is to only have a slip-resistant sole.


It’s slip-resistant, has a closed heel area, as well as an energy absorption heel, and is antistatic.


Has all the O1 features, and prevents water penetration.


Has all the O2 features and also has a midsole penetration resistance.


Has all the O1 features, but applied to footwear made with rubber uppers or polymer uppers.


Has all the O4 features and a midsole penetration resistance.


The slip resistance is a very important feature for your daily work. A small fall can cause serious injuries. To prevent it, safety footwear is tested and then classified into three slip-resistance categories.

- SRA footwear passed the test on ceramic tile wetted with a soap solution.

- SRB footwear passed the test on steel with glycerol.

- And SRC footwear passed both SRA and SRB tests, so it's the highest slip-resistant level.


A - Antistatic footwear

E - Energy absorption heel

P - Midsole penetration protection

C - Conductive footwear

WRU - Water-resistant upper

WR - Water-resistant footwear

CI – Cold Insulation Resistance

HI – Heat Insulation Resistance

HRO - Heat resistant

FO - Sole's resistance to Fuel Oil

M - Metatarsal protection (only for EN ISO 20345)

AN - Ankle protection

CR - Upper's cut resistance


Now that you know the meaning of each safety footwear code, it's time to put it into practice and choose your footwear.

First, you have to consider your job or activity for which you need safety footwear. If it's for construction, you have to look for a boot with a protective toe cap and midsole penetration protection, which means you can choose between S3 or S5 footwear.

On the other hand, if you work on gardening or if it's just a hobby that you love, there's no need for toe caps or protective midsoles. In this case, you can choose an O4 waterproof boot.

Do you want to find the perfect footwear for your activity? Click here and see our footwear recommendations for each area of activity.