Which types of ACP cladding are fire-safe?

You see modern buildings wrapped in sleek metal panels, but then you read shocking news about fires spreading rapidly up these same buildings. This contradiction makes choosing a safe cladding material feel incredibly risky.

Truly fire-safe Aluminum Composite Panels (ACP) are those with a fire-retardant (FR) core. These panels are classified as A2 or B1 grade and contain a high percentage of non-combustible minerals, like aluminum hydroxide, mixed into their core.

The entire conversation around the safety of ACP cladding comes down to one hidden component: the core material¹ sandwiched between the two aluminum skins. As a manufacturer of aluminum hydroxide, one of the key safety ingredients, I can tell you that what’s on the inside makes all the difference between a safe building and a potential disaster. The aluminum itself doesn’t burn, but the core can. Understanding this distinction is the single most important factor in selecting a product that protects property and lives.

Is ACP cladding flammable?

You are told that ACP is a metal product, which sounds safe. But the pictures of building fires tell a different story, creating a lot of confusion and concern.

Yes, traditional ACP with a 100% low-density polyethylene (PE) core is extremely flammable. However, modern fire-retardant (FR) ACP, which uses a core filled with minerals like aluminum hydroxide, is designed to be self-extinguishing and is very safe.

The problem with ACP never came from the aluminum itself. The issue lies with the core material that gives the panel its thickness and rigidity. The original, and cheapest, version of ACP used a core made of polyethylene (PE). This is a plastic that is very similar in chemical makeup to gasoline. When it is exposed to fire, it acts as a significant fuel source. It not only burns rapidly but also melts and drips, creating falling droplets of fire that can spread the blaze to lower floors and surrounding areas. This is why you see regulations tightening all over the world. The industry’s solution was to replace this flammable plastic² with a smart composite core, which we will discuss next.

What type of cladding is fireproof?

You want to eliminate risk entirely by choosing a "fireproof" material. But this term is used very broadly, and you need to know what it truly means in practice.

Truly fireproof materials are non-combustible, like stone, brick, or solid metal. In the world of composite cladding, an A2-grade ACP is considered non-combustible and is the safest, most fireproof option available.

The term "fireproof" technically means the material will not burn under any circumstances. While materials like solid stone fit this description, they are very heavy and expensive to install. The innovation of A2-grade ACP was to achieve this same level of safety in a lightweight, modern panel. The secret is in the core’s recipe. An A2-grade core is made of more than 90% non-combustible mineral filler. Our aluminum hydroxide is a primary choice for this. The remaining portion is a small amount of polymer that simply acts as a binder to hold all the mineral powder together. When exposed to fire, this core contributes almost no fuel to the flames. It provides the highest level of fire safety for tall buildings and critical infrastructure, meeting the strictest building codes worldwide. It offers the performance of a fireproof material with the design flexibility of a composite panel.

Is ACP sheet fire resistant?

The terms "fire resistant" and "non-combustible" sound similar. This makes it difficult to understand the exact level of safety you are purchasing for your project.

This depends entirely on the type. A standard PE-core ACP sheet is not fire-resistant. A fire-retardant (FR) ACP sheet, with a B1 or A2 rating, is fire-resistant, designed specifically to limit the spread of fire.

"Fire resistance" is about performance during a fire. A material that is fire-resistant will not necessarily refuse to burn at all, but it will make it very difficult for a fire to start and spread. This is where the chemistry of our aluminum hydroxide (ATH) becomes so important. When an FR ACP sheet is heated by a fire, the ATH mixed into its core begins a chemical reaction. This reaction does two critical things simultaneously. First, it absorbs a large amount of heat energy, which actively cools the panel down from the inside. Second, it releases its chemically bonded water molecules as harmless water vapor. This vapor smothers the fire by displacing the oxygen it needs to burn. The result is that the panel will char in place but will not spread the flames up the building. This built-in-safety mechanism is what gives the classification "fire resistant."

What type of cladding is flammable?

You need to know exactly what materials to avoid. Being able to identify the dangerous options is just as important as knowing the safe ones.

Any cladding panel with a core made of 100% unmodified polyethylene (PE) is highly flammable and dangerous. This is the lowest-cost and oldest type of ACP and should be avoided for almost all architectural applications.

The most critical red flag to look for when sourcing ACP is a 100% PE core. As an experienced buyer, you know the importance of checking specifications. For ACP, the fire classification³ of the core is the most important spec to verify. If a supplier cannot provide a fire safety certificate⁴ or a technical data sheet that clearly states the panel is "FR," "A2," or "B1," you should assume it is the flammable PE grade. There is no visual difference from the outside, so you must rely on the documentation. While other cladding materials like certain wood panels can also be flammable, the combination of high flammability and melting behavior makes PE-core ACP uniquely hazardous for multi-story buildings⁵. Always demand the fire-rated certificate.

Conclusion

To ensure cladding is fire-safe, you must choose an Aluminum Composite Panel with a fire-retardant (FR) core. Always verify the fire classification (A2 or B1) and avoid flammable PE cores.