EN 1090-3 for aluminium: certification and the differences with steel

EN 1090-3 contains the technical requirements for making aluminium structures, such as curtain wall frames, load-bearing profiles and canopies in aluminium. Together with EN 1090-1, the rules for the manufacturer, it forms the basis for CE marking of aluminium. According to Bouwen met Staal (Dutch steel construction information platform) , part 3 applies to aluminium and part 2 to steel.

For the certificate itself, it makes little difference whether you make steel or aluminium. In both cases you need an FPC system and a notified body. The difference lies in the technical execution: the material, the welding and the surface preparation. The execution classes also apply to aluminium.

Short answer: aluminium has its own technical standard (EN 1090-3), with its own requirements for welding and material. The certificate at manufacturer level works the same way as for steel.

Why aluminium has a separate standard

Aluminium behaves differently from steel. It is lighter, it has a lower stiffness and it reacts differently to heat. When welding, you lose more strength in the heat-affected zone, and the surface needs different preparation. For this reason, the steel rules are not simply adjusted. Instead, there is a standard of its own.

For the workshop, this means you have different material, different welding processes and different checks. A steel fabricator who wants to make aluminium must adapt the way they work, not just swap the material.

Steel and aluminium side by side

The table below gives the main points. It is an overview, not a replacement for the text of the standard. Check every requirement in EN 1090-3 before you rely on it.

Subject	Steel (EN 1090-2)	Aluminium (EN 1090-3)
Material	Steel grades such as S235 and S355	Aluminium alloys, for example 6061 or 6082
Welding process	Often MAG or electrode	Often MIG or TIG
Qualification of welding procedure	EN ISO 15614-1	EN ISO 15614-2
Qualification of welder	ISO 9606-1	ISO 9606-2
Heat-affected zone	Limited effect on strength	Clear loss of strength, to be taken into account
Surface preparation	Degreasing, blasting, coating	Degreasing, deoxidising, surface treatment
Material certificate	3.1 for structural steel	Material certificate from the aluminium supplier
Manufacturer certificate	EN 1090-1 with FPC	EN 1090-1 with FPC

The row on the heat-affected zone is the most important. For aluminium, you calculate with a lower strength in the area around the weld. This must be reflected in your design and in your WPS.

What does this mean for your WPSs?

A WPS (welding procedure specification) for aluminium is a separate document, with its own parameters. You cannot take over a WPS for steel. For aluminium, the qualification of the welding procedure is done under EN ISO 15614-2 (for steel under EN ISO 15614-1). You carry out the test weld on the aluminium you actually use.

The welding process range also differs. Aluminium often needs a different shielding gas and a different wire feed than steel. This makes it sensible to qualify aluminium welders separately, under ISO 9606-2.

Welders who only master steel are not qualified for aluminium. A steel certificate does not cover aluminium, even if the welder has experience.

Example: aluminium curtain wall frame in EXC2

A company makes a curtain wall frame from aluminium profiles for an office building. The designer chooses EXC2. The company must then comply with EN 1090-3 for the design and execution, and with the requirements that apply to EXC2.

The company does the following:

It records the material with a material certificate from the aluminium supplier, per alloy and per batch.
It prepares WPSs for MIG and TIG on the alloy used, with its own WPQR.
It qualifies the welders for aluminium under ISO 9606-2.
It carries out an ITP with hold points for the welded joints and the surface preparation.

The manufacturer’s certificate therefore covers the curtain wall frame. If the company had only steel procedures, its working method would not have properly covered the curtain wall frame.

What does the notified body want to see?

The notified body assesses your FPC system for aluminium separately. It wants to see that your aluminium processes are described, with their own WPSs and their own qualifications. It also looks at the surface preparation and at the registration of materials.

A common question is whether you mix aluminium and steel. This is a risk for traceability. Keep a clear separation in storage and in the work order.

Common mistakes

Reusing steel procedures. A WPS for steel is not valid for aluminium. This is the most common mistake among companies that switch from steel to aluminium.

No separate certificate for the welders. Use ISO 9606-2 for aluminium, not the steel qualification.

Confusion about the scope of the standard. Some sources describe the division of the parts differently. Check the scope in the standard itself and on your certificate.

An older version of the standard. EN 1090-3:2008 has been withdrawn and replaced by EN 1090-3:2019. Use the version stated on your certificate.

Frequently asked questions about EN 1090-3

Do I need a separate certificate for aluminium?

The manufacturer’s certificate covers the structures you make, provided you can demonstrate aluminium. Your notified body assesses whether you control the aluminium process. Ask your body which scope will appear on your certificate.

Can I combine aluminium and steel under EXC2?

Yes, if you control both processes and the separation in your file is clear. The classification applies per component.

Is the execution class different for aluminium?

The four classes are the same. The requirements that go with a class do differ per material. See the page on execution classes for the overview.

Where do I start if I only want to make aluminium?

Start with a gap analysis of your current FPC system, then the WPSs and the welder qualifications for aluminium. Use the costs page to estimate the lead time.