Grenfell Tower, a 24-storey apartment block in North Kensington, London, burns on June 14.
Grenfell Tower, a 24-storey apartment block in North Kensington, London, burns on June 14. ANDY RAIN

Plenty of Grenfell time bombs here

PEOPLE are living in ticking time bombs across Australia with fire authorities warning it's only a matter of time until a Grenfell Tower-type catastrophe happens.

There are possibly thousands of residential buildings with highly combustible polyethylene-cored aluminium cladding on exterior walls, experts believe. Polyethylene is more flammable than petrol.

And the cladding is on everything from apartment blocks to hospitals.

An investigation by ABC's Four Corners has exposed the widespread use of the cladding with a core of polyethylene, also known as PE.

"How many? It's unquantifiable ... it could be more than thousands,” Melbourne Fire Brigade deputy chief fire officer Adam Dalrymple said.

PE cladding covered London's Grenfell Tower and in June the world watched in horror as flames devoured its 24 storeys, killing more than 80.

Authorities across both countries are doing audits in the wake of the Grenfell tragedy, looking at all kinds of buildings that may be at risk.

The final death toll has not been determined, such was the severity of the blaze. The cladding was blamed for the rapid spread of the fire.

"I don't think there's a place for PE cladding on buildings at all,” fire engineer Tony Enright told the program.

However it's everywhere, thanks to the construction boom of the past two decades and an insatiable hunger for cheaper product.

And what was once a decorative design feature is now the main part of walls.

In 2014 a small fire on the eighth floor balcony of an apartment in the Lacrosse complex in Melbourne's Docklands precinct spread rapidly.

Within eight minutes flames had spread to the 21st floor, thanks to combustible cladding on the outside.

"A scenario such as Lacrosse, if it wasn't brought under control in a pretty quick amount of time, it could've claimed hundreds of lives,” Mr Dalrymple said.

"There's no doubt about that.”

Adding to the horror of the combustible cladding is that it melts away from its base when alight, sending flaming debris raining down below.

That can start new ignitions elsewhere in the building, as it did with the Lacrosse blaze.

And in windy conditions it can spread the blaze to surrounding structures - a risk amplified in very dense environments.

Melbourne fire authorities launched an investigation after the Docklands fire, led by Commander Mark Carter. He sent samples of the cladding to the CSIRO.

But it was so flammable that CSIRO had to suspend testing to avoid damaging its machines.

"How have we got a modern building like this, when we know what the construction code says about not having a combustible material on the outside?” Commander Carter said.

When Four Corners carried out the same kind of testing at CSIRO, it found even fire-resistant cladding was still combustible.

Alex Webb, a fire engineer at the institute, said three types of popular cladding - one with high PE, one with medium amounts and one with very little - were combustible.

"If a sample flames more than five seconds, that's combustible. We had to take the sample out because if we leave it in too long, all the material melts to the bottom and damages the equipment.”

Senator Nick Xenophon is part of a committee probing the use of dangerous building materials like cladding and said the time for ignorance is over.

"If there's a fire because of cladding and there are lives lost, then no doubt we'll have a royal commission, no doubt we'll have coronial inquests. People will be asking: 'Why weren't we warned about this?'

"Well, the fact is the warnings have been out there for years and this inquiry is basically saying there are no excuses not to act.”

Authorities across the country are carrying out audits in the wake of the Grenfell tragedy, looking at all kinds of buildings that may be at risk.

- staff writer