Fire behaviour of aluminium – what you should know

Aluminium is used in many areas of industry – from façade cladding and machine covers to vehicle components and electrical enclosures. However, especially in fire-sensitive environments, the question arises: how does aluminium behave in the event of a fire? Is it non-combustible, or can it promote fire? And which standards and classifications apply?

Aluminium and fire: the basics

Aluminium is one of the light metals with a melting point of around 660 °C. However, this property alone does not automatically make the material fire-safe. What is decisive is the form in which aluminium is present, as well as the external conditions. In solid form – for example as sheet, plate or profile – aluminium is non-combustible and shows very stable behaviour under exposure to heat. It can melt at high temperatures, but does not burn on its own.

The situation is different with finely distributed forms such as aluminium powder or swarf: these can react explosively given a sufficient supply of oxygen and an ignition source. In industrial practice, this means: solid aluminium products are considered hard to ignite to non-combustible, while special safety precautions may be necessary when processing aluminium – in particular during grinding or milling work.

Standards & fire protection classes: DIN EN 13501-1

In Europe, the standard DIN EN 13501-1 regulates the classification of building materials with regard to their fire behaviour. For aluminium, this standard is particularly relevant in construction, in façade systems and in architecture. Classification is made in levels A1 (non-combustible, no smoke development) to F (easily flammable). Solid, untreated aluminium sheets generally achieve class A1 or A2.

What is decisive, however, is whether the material is purely metallic or whether other materials are involved. Aluminium composite panels, for example, which contain a core of polyethylene (PE) or other plastics, often only achieve class B – they are therefore considered hard to ignite, but not non-combustible. Also relevant are the parameters s1–s3 (smoke development) and d0–d2 (burning droplets), which play a role in particular with façade elements and ceiling claddings. An exact classification is only possible on the basis of test certificates.

Melting behaviour & droplet formation

If aluminium is heated strongly, it melts without burning beforehand. This can happen at temperatures from around 660 °C, which can be reached, for example, in the event of a fire in industrial halls or vehicle fires. The following applies:

• No toxic gases are produced as with many plastics.
• Molten aluminium can spread further, but cannot continue burning on its own.

The high thermal conductivity of aluminium also ensures that heat is distributed very quickly – which can have advantages and disadvantages. Components heat up rapidly, but also cool down again more quickly.

Aluminium compared with other materials

Material	Burning behaviour	Toxic gases in the event of fire	Remark
Solid aluminium	Non-combustible (A1/A2)	None	Melts at approx. 660 °C
Aluminium composite	Hard to ignite (B)	Possible (depending on core)	Suitable only for certain applications
Steel	Non-combustible (A1)	None	Rapidly loses load-bearing capacity under heat
Plastic	Flammable (B/C/D)	Yes	Critical for many industrial installations

Toxicity & smoke development

A decisive advantage of aluminium over many plastics lies in its behaviour under exposure to fire. Aluminium does not develop toxic gases – neither when heated nor when melting. This means that no halogenated or harmful substances are produced that could be dangerous to people and the environment. Smoke development also remains minimal, which is of great importance in particular in enclosed spaces or escape routes.

This aspect makes aluminium a preferred material in safety-relevant applications, for example in public buildings, tunnel structures or vehicle interiors. In combination with other non-combustible materials, fire protection concepts can thus be realised that meet the highest requirements.

Applications with increased requirements

In the following areas, the fire behaviour of aluminium is particularly relevant:

Façade construction

Here class A1 or A2 is usually required. Uncoated, solid aluminium is suitable in many cases. For composite panels, special test certificates are necessary.

Machine claddings

Since aluminium does not burn and does not form toxic gases, it is well suited to claddings in mechanical engineering – for example in food technology or the chemical industry.

Vehicle construction

Despite its low weight, attention must be paid to behaviour in vehicle fires. Aluminium melts earlier than steel, but does not burn. A combination with heat-resistant materials is often advisable.

Electrical enclosures & control cabinets

Aluminium is preferred here because of its thermal conductivity and good fire protection behaviour.

Conclusion: planning fire-safely with aluminium

In solid, metallic form, aluminium is a very reliable material for fire protection-relevant applications. It does not burn, does not develop toxic vapours and in many cases meets the requirements of the highest building material class A1. Particularly in sensitive applications – such as façades, machine claddings or electrical enclosures – aluminium plays to its strengths.

Nevertheless, not every aluminium product is automatically non-combustible: coatings, composite materials or plastic-containing cores can influence the classification. Designers, buyers and planners should therefore always check the specific material specifications and test certificates. Only in this way can it be ensured that aluminium products are not only functional, but also reliable in the event of a fire.

Consider fire protection from the outset: get advice on the right aluminium sheet or configure your aluminium cut piece directly online – technically and in compliance with standards.

FAQ – Frequently asked questions

Does aluminium burn in a house fire? No, solid aluminium does not burn, but it can melt and cause damage in the process.

Which aluminium products are considered non-combustible? Solid sheets, plates and profiles without organic coatings usually achieve class A1.

Is aluminium safer than plastic in the event of a fire? Yes, aluminium does not develop toxic gases and is non-combustible.

What role does the PE core play in aluminium composite panels? It can be flammable. As a result, composite panels are often classified only as hard to ignite (class B).

Why is the thermal conductivity of aluminium relevant? It promotes rapid heat distribution – which can influence both the risk and the cooling down.