Aluminium composite panels: A material that fascinated Indian architects at the turn of the century.

In the 1990s India became an open economy. First foreign products poured into the markets, then came the services. Indians were suddenly exposed to a whole new world. Everything suddenly changed around us, so did the architecture. New markets developed, there was a sudden requirement for making IT Parks and Malls. Singapore became the new inspiration and even source of architects for the sudden need to make so many new buildings. Among many things that changed around us, one thing I remember was a sudden appearance of huge glass facades and aluminium composite panels (ACP) all across my city (Pune). In 2001, when I passed my architecture, after studying Charles Correa, all this was hard to comprehend.

Recently ACP was in the news for all wrong reasons after the Grenfell tower fire incident in London in which a building material was responsible for many deaths. I thought it will be good to look back what transpired in India back in the late 1990s and have a re-look at the rise and rise of ACP as a building cladding material.

Why such fascination?

Most of the new millennium architecture in India is mostly inspired by two cities. First, it was Dubai, the next was Singapore. It’s important to note that Dubai has probably the highest concentration of ACP use in the world, for a city of its size.When Indian cities began to grow at rapid pace post economic liberalization, a lot of architects from Dubai and Singapore ventured into projects in India. That probably was the catalyst in the boom of ACP buildings in the metros.

There were more reasons though. ACP cladding was pretty low maintenance, easy and fast to install and pretty finished to look at. Builders and contractors found a very fast and easy way to achieve finishes on the building exteriors, which otherwise requires skilled labour or formwork. It was fast money and real estate was booming. Everybody wanted to build, and fast. Moreover, most Indian metros previously looked decapitated by monsoon stains on low-quality paints, and poor exterior finishes. ACP clad buildings stood out of the lot.

Forget new buildings, people started wrapping up old buildings in ACP, for quick and low maintenance facade upgrade.

Impact on architecture

The next 5 years saw ACP clad buildings popping out at every street corner. By 2005, commercial buildings and IT parks had only one look across cities. They were masses built of glass and ACP. As the demand increased, new players joined in. Every company that made construction materials now sold ACP too in various colours and textures. ACP was never supposed to be a cheap substitute for other existing external finishes, but it turned out to be exactly that, in absence of proper safety and quality guidelines.

Architects were loaded with work. Here was a material that looked like a quick fix for everything. The builders were happy too. Cities like Mumbai and Bangalore lost their visual identity at a rapid pace. Bad copies of designs used in the South East Asia and Dubai were rampant.

The positives of aluminium composite panelling

Let’s understand the basics first. Aluminium composite panels (ACP), are flat panels consisting of two thin coil-coated aluminium sheets bonded to a non-aluminium core. The core is commonly low-density polyethylene (PE), or a mix of low-density polyethylene and mineral material to exhibit fire retardant properties.

ACP remains one of the most innovative, researched and improved construction material of our times. Strict quality controls in the developed nations and a conscious approach towards material applications in the west have resulted in many European and American manufacturers to innovate. Some of the benefits of using high-quality ACP can be summarised as below:

  • Flatness and visual consistency
  • Light in weight
  • Weather resistance across a wide range of weather conditions
  • Formability
  • Recyclable

Many iconic examples of modern architecture have ACP cladding including numerous ones in India. To say that the use of ACP is bad is a flawed argument. One of the most important decisions an architect has to take while designing is the use of materials. The material itself should never be blamed.

ACP and the fire hazard

One thing that was consistently overlooked in the initial years of ACP usage was safety. Even the developed economies had few safety standards that could test and accommodate an entirely new concept of building material like the ACP. As a result, when defects were noticed, it was too late. And the defects came to light because of some major disasters, the latest and the most prominent one being the Grenfell Tower fire in London.

At the core of the issue is the polyethylene (PE) used in between the two thin sheets of metal. The material used for the core of most ACPs are extremely flammable. Something the existing regulations in cities like London, Dubai and Melbourne failed to measure. The focus of fire safety was only on FR or fire resistance in terms of time. The fire propagation of materials on exterior wall assemblies is actually assessed through the Multi-Story Fire Propagation Wall Assembly Test, NFPA 285, which became an industry standard much later. Consequently, many of the wall assemblies utilizing ACP in major cities in India, are substandard since the norms of the day were not adequate in addressing the exterior cladding flame spread issue, at the point of installation.

ACP and sensible design

It’s important to understand that ACP is a modern material, though now it has existed for a long time. Cladding old building facades with ACP can be hazardous, especially if it’s a tall building. Modern buildings have better firefighting systems on all floors, including sprinklers, which are absolutely essential to fight ACP fires in tall buildings. Exactly the point why the Grenfell Tower was such a disaster.

Wrapping up ACP along the insides of ducts is another recipe for disaster. The duct becomes a shaft for a fire to shoot upwards with a good supply of oxygen; ducts are for ventilation right?
Continuous vertical facades are pretty dangerous. The designer has to know how to break the vertical spread of fire in case of fires by using fire stops at the line of each floor plate to prevent the fire from spreading up the facade.

All of these are however fire safety guidelines. A very holistic approach towards the use of the material is also very critical. At the least that we should do is to avoid wrapping up old structures in ACP, or use ACP just as a cheap and fast material. If the design demands the use of ACP, so be it. Till we have something that compliments glass better, ACP will remain one of the most sought-after materials in the construction industry.

Another more important need of the day is having updated fire safety regulations. Since the fire incidents, UK, Dubai and Australia have made laws more stringent. Whether we have done so in India remains the most important question now.

Sayantan GuptaAbout the author:

Sayantan is an avid architecture enthusiast. After graduating as an architect in 2001, he still pursues this vast domain with the energy and enthusiasm of a student.

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