EN 15085

CL1 VS CL2

CL1 vs CL2 vs CL3: Understanding EN 15085 Classification Levels Correctly

By First Welding Certification Technical Editorial Team

6 Min Read

31 Aug 2026

EN 15085 CLASSIFICATION AT A GLANCE

The safety relevance of the welded component determines the certification level.

CL1

Structural & safety relevance

CL2

Functional equipment

CL3

Auxiliary component

What Do CL1, CL2 and CL3 Mean in EN 15085?

In the case where the manufacturers meet EN 15085 for the first time, the most popular question would be:
“Should we apply for CL1, CL2 or CL3?”
The answer will not start with the question of what kind of class is higher and better.
In accordance with EN 15085-2, the manufactures of the welded products and the products themselves will be classified according to the significance of the welding product with regard to the safety of the railway vehicle.
This is especially true in the case of the manufacturers of railway vehicles and railway components, since the same manufacturer can produce various types of welded products with different safety requirements.

Classification	Typical Scope	Permitted Weld Performance Classes (CP)	Key Quality Requirement
CL1	Railway vehicles and welded components within the CL1 certification scope	CP A, CP B, CP C1, CP C2, CP C3, CP D	EN ISO 3834-2
CL2	Railway vehicles and welded components within the CL2 certification scope	CP C1, CP C2, CP C3, CP D	EN ISO 3834-3
CL3	Railway vehicles and welded components within the CL3 certification scope	CP D	EN ISO 3834-4

The existing EN 15085-2 classification system also entails that a company which meets the CL1 requirements for a certain task may also conduct the CL2 and CL3 operations for the same task, while CL2 companies may undertake the CL3 operations.

How Is the Applicable Classification Determined?

The classification should be established from the actual welded product or component rather than simply from the size, complexity or commercial importance of the manufacturer.

A practical assessment should consider:

What railway product or component is being manufactured?
What function does the welded component perform?
What could happen if the component fails?
What welding requirements apply?
What weld safety category is applicable?
What manufacturing and welding activities are included in the certification scope?

EN 15085-2 provides classification levels and allocations for common railway components, while also allowing certain deviations where the applicable requirements are properly documented and justified.

Reference pointer: EN 15085-2, Clause 4.1 — Classification level.

CL1: What It Covers

CL1 is applicable to welded railway vehicles and components having the corresponding highest safety relevance according to the classification.
There are examples of major structures and components classified as CL1 in CL1 such as certain bogie structures, underframes, car bodies, and other welded assemblies which have corresponding safety relevance.
But CL1 cannot just be considered as “the best welding certification”.
This indicates that the manufacturer is operating within the scope of the certification relating to components having the corresponding safety relevance and should also comply with the requirements of the classification.
EN 15085-2 also provides quality requirements for CL1 activities, such as EN ISO 3834-2 for welding activities.

CL2: What It Covers

CL2 is applied to welded rail vehicle components with the respective medium safety level.
However, this does not imply that CL2 implies “average-quality welding.”
In CL2 certification, controlled welding process, proper welding coordination, qualified personnel, adequate procedure, inspection and documentation specified for the respective scope are needed to be demonstrated.
It should be noted that according to EN 15085 classification criteria, welded joints with high safety level cannot be included in CL2.
As for CL2 related operations, the respective quality criteria refer to EN ISO 3834-3.
Thus, CL2 can be explained in terms of:
Classification of component + weld requirements applicable to it + manufacturing operation.

CL3: What It Covers

CL3 class applies to welded parts of railways according to their respective lower safety category.
Again, this doesn’t imply that a CL3 welder manufactures substandard or insignificant products.
Classification depends on the safety of the respective part of welded joints.
According to the classification criteria, high or medium safety category welded joints cannot be used for CL3.
In respect of applicable CL3 operations, quality standards are linked with EN ISO 3834-4.
That’s why one shouldn’t classify an operation as CL3 merely because a part of joint is cheap or easy-to-work.

Why CL1, CL2 and CL3 Should Not Be Treated as Quality Grades

One of the common misconceptions about EN 15085 is considering CL1, CL2 and CL3 as a hierarchical classification system.
Such as:
CL1 = excellent
CL2 = acceptable
CL3 = basic
It is not the proper interpretation of the classification.
The proper question is:
What is the safety significance of the welded part, and what classification and welding procedures should be used for that part?
A tiny part may have an essential safety function, and on the other hand, a huge part is not necessarily CL1 due to its dimensions.
Thus, the classification should be considered with engineering and normative view.

Where Weld Performance Classes and Safety Categories Fit

Another important distinction is between the manufacturer classification level and the weld performance/safety requirements applicable to individual welded joints.

These concepts should not be mixed together.

EN 15085-2 establishes CL1, CL2 and CL3 manufacturer/component classification, while the applicable welding requirements are determined through the relevant provisions of the EN 15085 series.

This means that selecting CL1, CL2 or CL3 is not the end of the technical assessment.

The manufacturer must also establish the applicable welding procedures, personnel competence, inspection requirements, documentation and production controls.

For a broader explanation of the certification requirements, see EN 15085 Certification Requirements.

WPS, WPQR and Welder Qualification

Classification according to EN 15085 standards does not eliminate the need for weld procedures and personnel qualification.
Depending on the welding process used and the product requirements, the manufacturer may require:

Welding Procedure Specifications (WPS)
Welding Procedure Qualification Records (WPQR)
Qualification of the welder
Qualification of welding operator
Welding coordination
Inspection personnel
NDT personnel
Tracing of material
Production Document

A WPS describes the procedure of welding, while WPQR proves the procedure qualification.
You can find additional information regarding this connection in WPS vs WPQR.
Personnel qualification should be taken into account along with manufacturer’s welding system and scope of certification.

How to Determine the Correct Classification

In order to get ready for EN 15085 certification, one can use this sequence of actions:
1. Define the railway product
Define exactly what kind of vehicle, parts or assemblies are produced, changed, repaired or supplied.
2. Define the welded parts
Decompose the product into its actual welded parts and assemblies.
3. Define the safety relevance
Assess the consequences which will occur due to the failure of the part being welded.
4. Assess the EN 15085 requirements
Study the classification, welding and production requirements.
5. Define the welding activities required for certification
The scope of certification can include design, production, maintenance or procurement and supply depending on the manufacturer’s activities.
6. Study welding controls
Study WPS, WPQR, welders, welding operators, welding coordination, inspection, NDT and traceability.
7. Define the scope of certification
After all these steps are taken, the certification scope (CL1, CL2 or CL3) is defined.
If you need to get certification, you can study our EN 15085 Certification.

Frequently Asked Questions

What is EN 15085 CL1 certification?

EN 15085 CL1 is the classification level associated with welded railway vehicles and components having high safety relevance

What is the difference between EN 15085 CL1 and CL2?

CL1 is for high safety relevance of welded railway vehicles and components, and CL2 is for medium safety relevance. The applicable classification level should be established depending on the welded components and their applicable safety relevance and requirements rather than chosen arbitrarily by the manufacturer.

Is CL3 lower than CL2?

There is no universal answer based solely on the term “TBM.” First establish whether the machine falls within the relevant railway or track-bound application and then assess the safety relevance of its welded components.

A conventional civil tunnel boring machine should not automatically be classified under EN 15085.

Which EN 15085 certification level does my TBM need?

There is no universal answer to this question since you cannot just use the term “TBM” to define the applicable certification. Determine first if the equipment qualifies as railway equipment or track-bound equipment and then analyze the safety relevance of the applicable welded components. A conventional civil tunnel boring machine should not necessarily be considered for EN 15085.

Is WPS & WPQR required for EN 15085 certification?

Welding procedure is an integral part of controlled welding production but the specific procedure and its qualification requirements depend on the process and the specific product. If qualification of the applicable welding procedure is required, the procedure should be qualified. WPQR can provide such qualification.

Conclusion

Knowing about the EN 15085 CL1, CL2 and CL3 is much more complex than just putting all three classifications in a hierarchy from “high, medium and low”.
The proper way is to start from the welded railway product, comprehend its importance and safety aspects, determine the relevant welding standards and consequently define the certification scope.
Therefore, CL1, CL2 and CL3 cannot be regarded as only the levels of the quality of welding but also classification levels that are included in the EN 15085 manufacturer certification scheme and have relation to the safety aspect of the welded products.
In such a way, for the manufacturers, a proper determination of the classification at the very beginning will help to avoid mistakes and problems in the future.

Need EN 15085 Certification?

First Welding Certification Pvt Ltd (PRVÁ ZVÁRAČSKÁ, a.s.) functions as a Manufacturer Certification Body (MCB) for EN 15085 certification within the relevant scope of recognition and certification. The EN 15085 certification provided by us is recognized via ECWRV, with the certificates issued by First Welding Certification Pvt Ltd(PRVÁ ZVÁRAČSKÁ, a.s.) and registered within the relevant EN 15085 certification register.
In case there is doubt as to whether your railway product or the welded part is categorized under CL1, CL2 or CL3, the appropriate way to go is by conducting an assessment of your real product, welded parts, activities and certification scope.
Discuss Your EN 15085 Certification Requirement with First Welding Certification Pvt Ltd