Hard to tell which cladding is safe or flammable - NZ contractor

Councils around New Zealand are being asked to check the cladding on high-rise buildings after a devastating fire tore through a London apartment block.

The tower had an aluminium composite cladding. The material has been blamed for several building fires around the world, including the 2015 Docklands blaze in Melbourne.

ACM (Aluminium Composite Material) also known as ACP (Aluminium Composite Panel) is not prevalent in New Zealand, Minister for Building and Construction Nick Smith told The AM Show on Friday.

He couldn't say how long the product has been used here.

ACP in NZ for decades

But a New Zealand cladding company told Newshub aluminium composite panels have been used on buildings here since the 1980s, and possibly earlier. 

The company, which didn't want to be named, told Newshub it only uses fire-rated ACP cladding with a mineral core, but says there has been a lot of lower-cost, non-fire-rated material used in the industry. 

The lower-cost material often has flammable polyethylene in its core, which is what was in Grenfell Tower's cladding.

But it's hard to tell the difference between that and the fire-rated mineral-core ACP, unless samples are taken and tested.

Dr Smith said: "With the significant fires that occurred in Melbourne and Dubai in multi-storey high-rise buildings we made decision on January 1 this year to prohibit the use of these sorts of combustible cladding products [on buildings over two storeys tall]."

Councils to check buildings

Dr Smith said the advice he's had is that it's unlikely the cladding has been used in New Zealand on high-rises, but he has asked officials to check with main city councils to see if any newly-constructed buildings have used it.

"This composite aluminium product's only been around for a few years, and so it's unlikely it's been used on old buildings, unless it's a refurbishment."

The Grenfell Tower was an older building that had its cladding recently refurbished.

"It's relatively modern building material - it is suitable for low-rise buildings, it is not suitable for high-rise; that's why we moved on January 1 and banned it," says Dr Smith.

"I think there'll be tough questions in Britain as part of the inquiry as to why other jurisdictions like New Zealand banned this product, but it was allowed in the UK."

Fire engineer Stuart Harris told The AM Show there will be some taller buildings in New Zealand with the cladding, "but I think the big picture is the cladding is not the problem itself". 

Systems 'more important' than cladding

"Fire safety of the building is a combined thing it's about the cladding that's on the building but more importantly it's on the systems."

If high-rise buildings with the combustible product are found, Dr Smith said fire engineers will investigate and advise on safety modifications.

"It's not just one line of defence. I'm advised there's not a single building in New Zealand where people are advised to stay in the building [this was reportedly the advice in the Grenfell Tower]. The consistent advice in New Zealand is 'evacuate'.

"Secondly, we have far stricter requirements in terms of sprinklers - that was absent from that Grenfell building."

He says he's looking at tougher requirements for New Zealand high-rise buildings around access for fire engines and firefighters, and access to water.