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Warning on ACM Panels – McCourt’s ReVerb

Friday, 30 June 2017
By Andy McCourt

External cladding similar to that used on Grenfell Tower has been discovered on a four-storey accommodation block in Perth, WA.

Since their invention in 1964 by Alcan (now 3A Composites), Aluminium Composite Panels have proved to be an excellent medium for screen print use in signage, display, POP and, more recently, digital inkjet decoration using flatbed UV printers. Correctly used and fabricated, ACM is yet another reason why wide format inkjet printing continues to outstrip most other areas of the graphic arts in growth and versatility.

From the instant I saw the first news footage of the Grenfell Tower inferno here in the UK, I could see the building had been clad in ACM panels and wondered if they were the correct grade. In my mind was the 2014 Lacrosse Building fire in Melbourne, where a third party had wrongfully used the PE (Polyethylene) cored ACM product which resulted in an intense and rapidly spread fire that destroyed the building but, mercifully, no lives were lost.

The Grenfell London high-rise fire so far has killed 79 people including children and babies. The rapid spread of the fire both up and down the building has focused attention on the ACM cladding used in a recent renovation. Subsequent investigation has revealed up to 600 residential tower blocks in the UK may have the same non-fire retardant cladding. Nine buildings have already begun removal of ACM cladding, with more to follow.

Scotland Yard has commenced a criminal investigation to see if deliberate use of the cheaper, PE-cored ACM instead of the more expensive mineral-cored fire-resistant ACM, has occurred. If it proves to be so, it is not inconceivable that prison terms could eventuate for suppliers, installers and specifiers. If deliberate substitution of ACM material has occurred, the charges will be very serious indeed, some UK media even calling it mass murder.

Why PE-core ACM spreads fire so fast

On its own, ACM does not typically start a fire but if one does start (Grenfell ignited from an exploding fridge), the PE core can ignite, drip flaming globules down while accelerating upwards through the gap in the ACM sandwich. As it gets hotter and hotter, it sucks oxygen in and effectively becomes a blast-furnace, fuelling even hotter and more violent combustion at very high speed. The melting point of aluminium is around 660 celsius: the London Fire Brigade estimate that Grenfell peaked at well over 1,000C so you can imagine what happens to the thin aluminium facings – made from coil rolled aluminium in the same way offset plates are made.

The result is a horrible, inhumane and completely avoidable holocaust of death, maiming and family tragedy. Contributing to this in an almost mind-boggling omittance, is that Grenfell Tower had no sprinkler system and neither do most of the other council-run low cost accommodation blocks in London.

What to do in Australia and New Zealand

Our industry importers of ACM suppliers are many and varied, from top-grade well documented ACM with appropriate warnings, to cheap Asian imports of questionable specification and testing. Used only for signage, POP and display and there is no problem whatever is used. It’s a great medium for excellent quality UV printing and fabrication.

For architectural and construction use, PE-cored ACM must never be used but we know from the Lacrosse Building fire that it has. Who knows how many other buildings are potential blast-furnace infernos? A full UK-style inspection is needed and removal undertaken if PE core is found.

If ACM suppliers see a large order for PE-cored ACM that is uncharacteristic, they must ensure it is for signage use alone. The mineral ‘wool’ cored ACM contains a hardened slurry of rock or slag and has a higher melting point than even the aluminium it joins. If it looks like the panels are going onto buildings, the more expensive fire-grade ACM must be supplied. Just as with our uranium, the supply chain must be monitored to end use.

If an architect specifies fire-resistant grade ACM and a contractor substitutes cheaper non-fire grade, this should then be a criminal offence. Just as concrete is tested prior to a big pour, ACM architectural panels should be spot-checked and tested prior to and during installation.

If you have already knowingly or unknowingly supplied or installed ACM panels for construction purposes that are not the fire-resistant kind, then for pity’s sake ‘fess up and notify the local authorities immediately.

Grenfell was and is an ongoing unimaginable horror and tragedy. Let’s make sure it never, ever happens in Australia or New Zealand. It’s something our industry can do something about, so let’s do it.







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