Aluminum Composite Panel has been a popular façade and cladding material over the past two decades. It holds many advantages as a building material, as seen in its popularity. However, it also has many disadvantages including its lethal composition that has caused fatal tragedies in recent times. These disasters have obviously brought this issue and the product responsible to the public’s attention. From this, many questions arise around what ACP actually is, why was it ever used, what are its advantages and more importantly why and how is it so dangerous? So, let’s take a closer look …
Aluminum Composite Panel, mostly referred to as ACP, was created back in the 1960’s. Its original design and purpose was a material for signage. However, by the mid to late 1980’s, the architectural and construction industry discovered this material and began using it as a building material. Its lightweight, yet durable properties made it a great façade material and soon it was being used internationally on residential and commercial properties, improving architectural performance and reducing costs.
At this time, nobody was aware of the highly combustible core that the original ACP consisted of. It’s potential to cause disasters came to light approximately 6 years ago, with many in the industry shocked by its flammable capabilities. Yet, it wasn’t until 2017 that the devastating Grenfell Tower tragedy made the industry ‘wake up’ and listen to those that had been warning of this for years.
So, what actually is ACP?
ACP is an external building cladding material used to create great-looking and durable facades. It consists of two thin aluminum sheets bonded to a non-aluminum core. It is typically 4mm thick, comprising of two 0.5mm aluminum skins bonded to the non-aluminum core, typically being 3mm thick.
As mentioned earlier this material was originally designed for signage, but soon became an integral material in the façade construction industry due to its almost countless advantages. These included:
- Lightweight – has a remarkable strength-to-weight ratio
- Adaptable and flexible – could be used around curves and corners, soon becoming the easiest material to use for ‘unusual shaped’ facades.
- Durable – very strong and durable, stood up to natural elements
- Versatile – came in a variety of colors and offered unlimited opportunities to architects.
- Low-maintenance – requires significantly less maintenance than other similar products (such as FC Sheet) due to its PVDF coating and finish.
From these points you can see why it became so popular amongst architects and builders alike. Yet there is still the striking disadvantage that wasn’t noticed when it came onto the building scene; Combustibility. The non-aluminum core of the original ACP was highly combustible, being constructed of polyethylene, a thermoplastic polymer with highly flammable characteristics.
The different types of ACP
Aluminum Composite Panel has developed a lot since the original, combustible design. The main difference is the core, which is really the entire problem. The material that makes up the core and how it is laminated to the aluminum is the key characteristic that has become known for defining whether the material is combustible or not. The different types of ACP and their relevant core construction and combustibility is outlined in the table below.
|Panel Type||Core Material||Fire Rating|
|PE (Polyethylene)||100% Polyethylene||Highly Flammable|
|FR (Fire Resistant)||Fire retardant core consisting of a low percentage of Polyethylene and a mineral fill.||Difficult to ignite and minimal spread of flame.|
|Solid Aluminum||Solid aluminum with no non-aluminum core or laminates.||Non-combustible|
The PE cladding is the cladding that has caused the building fires such as Grenfell, Docklands, Dubai and many more. Since these the other products have been developed to retain the advantages of ACP whilst providing a safer alternative. These other, safer alternatives also provide a great material to replace the current flammable ACP on buildings. This will minimize the cost of rectification due to installation being quicker and easier with less modifications to the building required. All ACP products still require thorough testing and certification by professional fire and safety consultants and engineers for any application.
The current situation
The issue this product has created is the serve risk presented by the many building facades consisting of this product internationally. The bigger issue is first identifying the buildings that do have ACP on them. Learn more about this issue and the steps to resolving it by visiting our article: The Combustible Cladding Issue: What’s it all about?