Aluminium composite panels (ACP), also known as aluminium sandwich panels, are a widely used construction and manufacturing material. ACPs are made from thin sheets of aluminium bonded to a polymer or mineral-filled thermoplastic core. Traditional cores include polyethylene (PE) or polyurethane (PU). However, because PE and PU cores are flammable, the composition of these core materials has changed over time (as has the regulations regarding their use in construction).
ACPs have become an integral product in the construction and manufacturing industries. They are commonly used as external wall cladding because they are extremely lightweight, easy to form, durable yet flexible and can be finished in an extensive range of style, colours and finishes.
ACPS are widely used in a range of construction and manufacturing applications. Common applications include:
- External wall cladding for building facades
- Interior design applications like decorative wall panelling
- Automotive, marine and rail vehicle construction and fitout
- Clean or cold environments like medical facilities, commercial kitchens or cold rooms
- Outdoor advertising like billboards and signage
- Office or commercial fitout applications like drop ceilings and partitions
- Outdoor surfaces and furniture
- Machine housings
- Container construction
When used for construction, ACPs don’t add structural integrity but can contribute to aesthetics, weather proofing and energy efficiency.
Origins of ACPs can be traced back to the mid-1960s when 3A Composites invented aluminium composites. The first commercial production of an ACP product started in 1969, and the product was patented in 1971. This patent expired in 1991 leading to an explosion of companies worldwide manufacturing ACP products. Some 200 companies around the world now manufacture aluminium composite products for construction and manufacturing applications.
Different types of ACPs
While there are many different brands and manufacturers, there are only a few different types of ACPs used for construction.
- ACP ‘FR’ products: These generally have a polymer core of about 30%. The higher proportion of polymers makes them a high fire risk.
- ACP ‘A2’ products: These generally have a polymer core of less than 10% and are a much lower fire risk than FR products
Other types of aluminium cladding panels include solid aluminium panels, such as Alfrex Solid, or honeycomb aluminium panels like Alucore. However, these are technically not ACPs since they are 100% aluminium and don’t include the composite core. Because these products contain no polymer core, they are completely non-combustible.
Benefits of ACPs
There are plenty of good reasons that ACPs are so commonly used in construction and manufacturing applications. They are:
- Lightweight with an impressive strength-to-weight ratio
- Adaptable and flexible and can be easily formed and shaped for facades and design
- Durable, weatherproof and corrosion resistant
- Aesthetically versatile and available in a wide range of colours, textures and finishes
- Low maintenance, requiring only occasional cleaning
ACP products can provide some additional benefits including noise reduction, insulation and energy efficiency benefits.
Fire safety and regulations
In recent years, the fire risk associated with ACPs have gained significant media attention. In 2017, fire decimated the Grenfell Tower in West London, killing 72 people. The rapid spread of the fire was mainly attributed to the old-style aluminium composite material used on the building’s facade.
In 2019, a fire at the Neo 200 apartment tower in Melbourne’s CBD was also attributed to outdated aluminium composite materials used as external cladding.
As a result of these incidents, and others, tough new building regulations have been brought in regarding the use of ACPs. In Victoria, FR products (i.e. ACPs with a 30% polymer core) no longer meet fire regulations and cannot be used on a multi-storey building without independent approval from the Building Appeals Board.
In the wake of the Melbourne Neo 200 fire, the Andrews Government established a world-first program to tackle high-risk cladding products. Cladding Safety Victoria is a $600 million program that aims to reduce the risk associated with combustible cladding on residential apartment buildings and publicly owned buildings.
Part of the program involves funding and fast-tracking the rectification of buildings with high-risk cladding.
Despite the recent concerns regarding the fire safety of aluminium composite materials, they remain an extremely popular, versatile and high-quality construction material. Changes to regulations regarding the use of FR ACPs, together with improved manufacture of A2, solid and honeycomb products means these products will remain in high use without the ongoing fire risk.