How to Read Safety Shoe Markings

1. Check the standard first: S or O?

Classes starting with S (SB, S1…S7) are safety footwear under EN ISO 20345, and all of them have a toe cap tested against impact and compression. Classes starting with O (OB, O1…O7) are occupational footwear under EN ISO 20347; they do not have a toe cap. For work with a risk of falling objects or crushing, an O-class shoe is no substitute for an S-class shoe.

2. Safety footwear classes (EN ISO 20345:2022)

To avoid repeating our detailed guides S1P vs S3 Safety Shoes: Differences and Steel Toe Safety Shoes Guide, which cover the S1P/S3 difference and steel vs composite toe caps, the table below briefly summarises each class.

3. Occupational footwear classes (EN ISO 20347:2022)

4. What do the additional markings mean?

5. Antistatic, ESD and electrical insulation are not the same thing

Antistatic (A): Allows static electricity built up in the body to discharge; under EN ISO 20345, the electrical resistance of the footwear is approximately between 100 kΩ and 1 GΩ.

ESD: For electronics manufacturing areas sensitive to electrostatic discharge (EN 61340-5-1). The permitted resistance range is narrower (approximately 100 kΩ–35 MΩ); ESD footwear is also antistatic, but not all antistatic footwear is ESD.

Electrically insulating footwear: Working on live (energised) lines requires insulating shoes/boots classified to EN 50321-1. Footwear marked antistatic or ESD does not provide electrical insulation.

6. 2011 label or 2022 label?

Products certified to both EN ISO 20345:2011 and EN ISO 20345:2022 can be found on the market. On 2011 labels you will see SRA/SRB/SRC; on 2022 labels SR is used instead, classes S6 and S7 have been added and FO has become optional. So when comparing two products, check not only the class code but also the edition of the standard shown on the label.

7. Reading the label in 5 steps

1. Find the standard number (EN ISO 20345 = safety footwear with toe cap, EN ISO 20347 = occupational footwear without toe cap).
2. Read the class code (S1, S3, S5, O1…) and compare it with the risks in your work.
3. Check the additional markings (SR, HRO, CI, WR, M…); if a feature you need is not on the label, do not assume the product has it.
4. If there is an electrical risk, pay attention to the difference between antistatic, ESD and EN 50321-1 insulation.
5. Assess shoe size (EU) and fit together with your work socks; base the final choice on your workplace risk assessment.

FAQ

What does S1P mean?
S1P is an S1 safety shoe with an added puncture-resistant sole. In addition to the S1 requirements of a toe cap, closed heel, antistatic properties and heel energy absorption, the sole has been tested against sharp objects. In the 2022 edition, puncture protection is shown by the marking P, PL or PS.

What do S1, S2 and S3 mean?
S1: toe cap, closed heel, antistatic and heel energy absorption. S2: S1 plus resistance of the upper to water penetration and absorption. S3: S2 plus puncture resistance and a cleated outsole.

What is the difference between S1 and S1P?
The only difference is puncture resistance: the S1P sole is tested against sharp objects such as nails, while S1 has no such protection. If there is a risk of nails, metal fragments or glass on the floor, S1P or S3 is preferred.

What is the difference between antistatic and ESD?
Antistatic footwear discharges static charge built up in the body within the range of 100 kΩ–1,000 MΩ. ESD footwear (EN 61340-5-1) works within a narrower resistance range to protect sensitive electronic components from electrostatic discharge. Neither provides electrical insulation.

When should safety shoes be replaced?
There is no fixed period. Replace the shoes if the toe cap has taken an impact or been crushed, if the sole has holes, cracks or worn-out tread, or if the upper is torn or has open seams. A toe cap that has taken an impact may have lost its protection even without visible damage. Follow the manufacturer's instructions for use and your workplace procedures.

What voltage can electrician footwear withstand?
The voltage up to which insulating footwear may be used is stated in the EN 50321-1 class marking on its label. Footwear without this class on its label does not provide insulation protection for live work, even if sold as "electrician" footwear.

What does S4 mean?
S4 is the class for safety boots with a waterproof body moulded entirely from polymer or rubber. It does not include puncture resistance; that feature is found in S5.

What does O1 mean for work shoes?
O1 is occupational footwear without a toe cap: it provides a closed heel, antistatic properties and heel energy absorption. Work with crushing or falling-object risks requires S-class footwear.

What does SRC mean?
SRC is the slip resistance marking in the old (2011) standard: an outsole that has passed both the ceramic tile floor with soap solution test and the steel floor with glycerine test. In the 2022 edition it has been replaced by the SR marking.

Are ESD shoes suitable for electricians?
No. ESD footwear protects sensitive electronic components from electrostatic discharge. Live electrical work requires electrically insulating footwear classified to EN 50321-1.

What is the difference between S5 and S3?
S3 is a shoe with a leather or textile upper that resists water penetration. S5 is a waterproof boot with a polymer or rubber body. Both offer perforation resistance and a cleated outsole.

Related categories

Foot Protection · Safety Shoes · Safety Boots · Safety Wellington Boots · Occupational Shoes (No Toe Cap) · Electricians' Work Shoes