When an importer receives a safety shoe specification, the product name often tells very little about its actual protection.

A catalogue may describe a product as a “steel toe work boot,” “S3 safety shoe” or “industrial waterproof boot.” For a professional buyer, however, those descriptions are only the starting point.

The more useful information is found in the standard and the complete marking.

The principal international standard for general-purpose safety footwear is ISO 20345:2021 — Personal protective equipment — Safety footwear. ISO describes it as covering basic and additional requirements for safety footwear, including areas such as mechanical risks, slip resistance, thermal risks and ergonomic behaviour.

For PPE buyers, distributors and safety footwear brands, understanding ISO 20345 helps answer three practical questions:

What protection has the footwear been designed to provide?

What does its classification actually mean?

Does the documentation match the product being purchased?

This guide focuses on those questions rather than repeating a general safety shoe buying guide.

What Is the Current ISO Standard for Safety Footwear?

The current published international standard is:

ISO 20345:2021 — Personal protective equipment — Safety footwear

ISO published this edition in 2021 and subsequently published ISO 20345:2021/Amd 1:2024 — Amendment 1 in January 2024.

ISO also lists the previous ISO 20345:2011 edition as withdrawn.

This matters when reviewing supplier documents.

A product specification written several years ago may use terminology associated with an older edition, while a newly developed product may be tested and marked according to newer requirements.

For buyers, therefore, the standard number should never be read without its edition or amendment reference.

What Makes Footwear “Safety Footwear” Under ISO 20345?

ISO distinguishes safety footwear from ordinary work shoes partly through its protective toe requirements.

ISO’s definition states that safety footwear is fitted with toe caps intended to provide protection against impact of at least 200 joules and compression of at least 15 kN.

That is an important starting point, but ISO 20345 covers much more than the toe cap.

The standard also includes basic and optional requirements relating to areas such as mechanical risks, slip resistance, thermal performance and ergonomic behaviour.

Therefore, two shoes can both contain 200 J safety toe caps and still have very different overall classifications.

That is why professional buyers should ask for the full footwear marking, rather than only asking whether the shoe has a steel or composite toe.

How to Understand an ISO 20345 Safety Shoe Classification

A classification such as:

S1PS

or:

S3S

is not simply a product grade.

It communicates a defined combination of requirements.

For buyers who regularly review safety shoe catalogues, understanding the structure is more useful than trying to memorize every product description.

SB — The Starting Point

SB represents the basic safety footwear requirements.

It establishes the foundation on which additional classifications build.

A product marked SB is therefore safety footwear, but that marking alone does not indicate all of the additional properties a buyer may need for a particular workplace.

This is why a buyer should avoid treating SB, S1 or S3 as simple “good, better, best” rankings.

They represent different combinations of performance requirements.

S1 — Adding Additional Functional Requirements

S1 builds on the basic requirements and adds further properties defined by the standard.

It is commonly encountered in safety footwear intended for environments where whole-footwear water resistance or more advanced penetration protection may not be the primary requirement.

For a buyer, the important point is that:

S1 identifies a combination of requirements rather than a specific shoe style.

A low-cut sport safety shoe and an industrial leather shoe can therefore share an S1-related classification even though their materials, appearance and intended users are very different.

Understanding P, PL and PS

Penetration resistance is one of the most important areas for buyers to understand because modern safety footwear can use different types of penetration-resistant inserts.

Rather than treating all “anti-puncture midsoles” as identical, current classifications distinguish between different constructions and test conditions.

P

P is associated with the applicable penetration-resistance requirements for a metallic insert.

Traditional steel penetration-resistant midsoles are a familiar example.

PL

PL applies to a non-metallic penetration-resistant insert tested under the applicable PL conditions.

PS

PS also applies to non-metallic penetration-resistant protection but under a different applicable test configuration.

This distinction explains classifications such as:

S1P
S1PL
S1PS

and:

S3
S3L
S3S

The letters do not simply tell you whether a midsole is “steel” or “fabric.” They refer to the penetration-resistance system recognized by the classification.

A Practical Buyer Lesson

A purchase specification that says only:

Anti-puncture Kevlar midsole

is incomplete.

“Kevlar midsole” is frequently used as commercial language for textile penetration-resistant components, but what matters for certification is the tested construction and resulting classification.

A stronger B2B specification would identify:

the required footwear classification + penetration-resistant component + supporting documentation.

ISO 20345 Classification Table for Buyers

The following is a practical way to read the main category families without repeating the complete technical standard.

The purpose of this table is not to replace the standard.

It is to help purchasing teams understand why apparently small changes in a code can represent meaningful differences in footwear construction.

ISO 20345 Additional Markings Buyers Should Recognize

Beyond the main S classification, a footwear specification may include additional symbols.

These markings provide extra information about tested properties.

A common purchasing mistake is to focus on the longest code.

That is not the objective.

A specification should contain the properties that are relevant to the intended footwear and workplace.

WPA and WR Are Not the Same Thing

One of the most useful distinctions for buyers is between upper water-related performance and whole-footwear water resistance.

A product may use treated leather or another upper material that performs well against water penetration and absorption without the complete shoe being classified for whole-footwear water resistance.

This matters because product descriptions frequently use terms such as:

water resistant

and:

waterproof

as though they mean the same thing.

They do not necessarily describe the same tested property.

For an importer buying footwear for genuinely wet working conditions, the correct approach is to check the complete classification and supporting test documentation rather than relying on the marketing name of the upper material.

This section belongs on an ISO page because it explains how to interpret an ISO-related marking, rather than providing a general waterproof footwear buying guide.

How to Read a Complete ISO 20345 Marking

Consider a product marked:

EN ISO 20345:2022+A1:2024 S3S SR FO HRO

A professional buyer should break the specification into separate pieces.

EN ISO 20345:2022+A1:2024

This identifies the applicable European adoption and amendment referenced by the footwear documentation.

S3S

This identifies the core footwear classification and the applicable penetration-resistance configuration.

SR

This indicates the relevant additional slip-resistance performance.

FO

This identifies outsole fuel-oil resistance.

HRO

This relates to resistance of the outsole to hot contact.

Reading the code in this way is much more useful than simply seeing “S3 safety boot” in a product title.

It also makes quotations from different suppliers easier to compare because buyers can identify exactly which claimed properties are the same—and which are not.

How to Verify ISO 20345 Safety Footwear Before Ordering

For B2B buyers, understanding the symbols is only half of the job.

The next question is whether the paperwork actually corresponds to the product being ordered.

A useful verification process can be built around five checkpoints.

1. Product Identity

Confirm that the model shown on the certificate or supporting documentation corresponds to the product you are purchasing.

Do not assume that two shoes using the same outsole automatically have the same certification status.

2. Standard Reference

Check which standard edition and amendment are shown.

ISO currently lists ISO 20345:2021 and its 2024 Amendment 1, while earlier ISO 20345:2011 is listed as withdrawn.

3. Classification

Check the complete code.

For example:

S1PS SR

and:

S3S SR FO HRO

should not be treated as interchangeable descriptions.

4. Safety-Critical Construction

Identify which components are relevant to the tested footwear.

Depending on the model, these may include:

• protective toe cap
• penetration-resistant insert
• outsole
• upper construction
• water-resistant system
• other certification-related components

5. Production Match

The final production specification should remain aligned with the construction represented by the approved documentation.

This is especially important for OEM and private-label projects where materials can be changed during costing, sampling or production preparation.

A Better Way to Write an ISO Safety Shoe Specification

Consider two purchasing enquiries.

Enquiry A

Need waterproof steel toe safety boots with anti-slip sole.

This describes the product generally but leaves many technical questions unanswered.

Enquiry B

Target classification: EN ISO 20345 S3S SR FO. Mid-cut leather safety boot with required whole-product construction and documentation. Please confirm toe-cap specification, penetration-resistant insert, outsole construction and certificate applicable to the proposed model.

The second enquiry gives the factory a much clearer development target.

This is particularly valuable before sampling because footwear classification can influence material selection and construction.

It can also reduce the risk of discovering late in development that a proposed component does not match the intended certification.

Why the Product Label and Certificate Should Tell the Same Story

For PPE buyers, one useful way to think about certification is as a chain:

Product specification → tested construction → documentation → marking → mass production

Those elements should be consistent.

Suppose a footwear model is tested with one penetration-resistant insert but a different insert is later selected to reduce cost.

Or a product is tested using one outsole formulation while production moves to another.

The appearance of the footwear may change very little, but a professional buyer should still ask whether the certification documentation remains applicable to the resulting construction.

This is why component control matters.

Certification is not just a PDF file supplied after sampling.

It is connected to the physical product.

ISO 20345 and ISO 20344: Different Roles

Buyers may occasionally see both ISO 20345 and ISO 20344 in footwear-related technical documents.

They serve different purposes.

ISO lists ISO 20345:2021 as the safety footwear requirements standard, while ISO 20344:2021 is the corresponding footwear test-method standard.

For most commercial buyers, this means:

ISO 20345 tells you what safety footwear is required to achieve.

ISO 20344 contains methods used to evaluate footwear characteristics.

You do not need to become a laboratory technician to buy safety shoes, but understanding this distinction helps when reading test reports.

Is ISO 20345 the Only Footwear Standard in the ISO 2034x Family?

No.

ISO’s foot-protection catalogue also includes separate standards such as ISO 20346:2021 for protective footwear and ISO 20347:2021 for occupational footwear.

This distinction is useful because product descriptions sometimes use “safety footwear,” “protective footwear” and “occupational footwear” as if they were interchangeable commercial phrases.

Within the ISO standards system, however, they refer to different standards.

For this page, the focus remains specifically on ISO 20345 safety footwear.

How Ocean Safety Shoes Controls Certified Production Consistency

At Ocean Safety Shoes, certification-related product development is treated separately from ordinary styling decisions.

Once the safety-critical specification for a project has been established, the focus during production should be on maintaining the approved construction.

For example, control points can include:

Toe-cap identification — ensuring the specified protective toe component is used for the correct model.

Penetration-resistant component control — preventing unapproved substitution between different midsole systems.

BOM control — recording the materials and components that belong to the approved product specification.

Incoming inspection — checking important materials before they enter production.

Sample-to-production matching — comparing mass-production construction with the approved development sample.

Finished-product inspection — confirming that production workmanship and identified components remain consistent.

For an OEM buyer, this approach is more valuable than simply asking whether a factory “has certificates.”

The key question is:

Can the manufacturer consistently produce the same safety-critical construction represented by the approved product documentation?

Frequently Asked Questions About ISO 20345

What is the ISO standard for safety footwear?

The principal international standard for general-purpose safety footwear is ISO 20345:2021 — Personal protective equipment — Safety footwear. ISO also published Amendment 1 in 2024.

How much impact protection does ISO 20345 safety footwear provide?

ISO defines safety footwear as incorporating toe caps intended to protect against impact of at least 200 J and compression of at least 15 kN.

What is the difference between P, PL and PS?

They identify different penetration-resistance configurations. P relates to the applicable metallic system, while PL and PS identify non-metallic penetration-resistant systems under their respective test conditions.

Does S3 automatically mean waterproof?

No. Upper water-related performance and whole-footwear water resistance are distinct requirements. Check the complete classification rather than assuming that the word S3 alone means a completely waterproof boot.

Why should buyers check the complete marking?

Because additional symbols such as SR, FO, HRO and WR communicate properties that the basic S classification does not fully describe.

What is the difference between ISO 20344 and ISO 20345?

ISO 20345 specifies safety-footwear requirements, while ISO 20344 provides footwear test methods.

Is ISO 20345:2011 still the current edition?

No. ISO currently lists ISO 20345:2011 as withdrawn and ISO 20345:2021 as published.

Conclusion: Read the Classification, Not Just the Product Name

So, what is the ISO standard for safety footwear?

For general-purpose safety footwear, the principal international reference is ISO 20345:2021, together with its applicable amendment.

But for professional buyers, the standard number alone is not enough.

A useful purchasing process is:

Standard → Classification → Additional Markings → Safety-Critical Components → Documentation → Production Match

That sequence helps buyers understand what a shoe is actually designed to provide.

It also changes the conversation with manufacturers.

Instead of asking only:

“Do you make ISO safety shoes?”

a professional buyer can ask:

“Which ISO 20345 classification applies to this model, which safety-critical components were used, and what documentation supports that construction?”

That is a much stronger starting point for an OEM or private-label safety footwear project.

Need to develop ISO 20345 safety footwear for your brand? Contact Ocean Safety Shoes with the required classification, footwear design and project requirements to discuss product development and controlled production.