Aluminium composite panels are a particular focus of the probe.
The panels, which are widely used to clad buildings, come in a variety of types. They have an inner and outer surface of sheet aluminium, typically separated by a non-aluminium core. In some cases, that inner core can be made of combustible plastic.
In Auckland, says McCormick, the 150-plus buildings being investigated "includes buildings with no ACP, ACP as a decorative feature, ACP with a polyethylene core and ACP that contains a modified core that has been subject to fire testing or no core at all.
"When in doubt, or if someone thinks it's ACP, it is on the list until we can satisfy ourselves to the contrary."
In deciding what buildings to check, the council has responded to public inquiries, contacted cladding suppliers and reviewed data to find buildings over 25m high.
The list includes residential and commercial buildings, says McCormick. Sixty-six of the ACP-clad buildings identified so far are more than 25m high, he says.
"If we identify a building that is considered dangerous, in conjunction with Fire and Emergency New Zealand, we will be taking immediate action to mitigate any risk."
Two buildings the council's experts have visited are the Nautilus, in Orewa, and the Spencer on Byron, in Takapuna. The council's fire engineers say there are no immediate concerns for people's safety in either building, says McCormick. "Any concerns over the cladding are well mitigated by other attributes of the building and the fire-safety systems in place.
"All the high rise buildings of any significance that we have identified all contain sprinkler systems as well as other fire-safety measures and are not considered to be an immediate safety concern for the occupants."
But John Gray, president of the Home Owners and Buyers Association, says fire-safety problems are widespread.
"We are gravely concerned about the serious structural and fire rating deficiencies that have been uncovered in every building we have been working in support of owners to repair," he says.
"These structural and fire protection deficiencies have presented a real and present risk to the lives of occupants in the event of an earthquake or serious fire."
Millions of dollars will now be needed to fix problems, Gray says, but buildings should have complied with consents and specifications regarding the control of smoke and fire.
After Grenfell Tower, Building and Construction Minister Nick Smith said he had been advised that similar cladding systems were uncommon here.
"I have asked the Ministry of Business, Innovation and Employment to contact councils and check whether any high-rise buildings have been constructed with these materials prior to the amendments earlier this year," Smith said last month.
Asked for an update this month, he said the primary checks were being carried out by councils.
"I have been advised of two buildings in Auckland having ACP and both are in the process of being remedied," he said, referring to Nautilus and Spencer on Byron.
McCormick says whatever cladding was used on a building would have been authorised by fire engineers who signed off the project when it was built.
"You could have combustible cladding on it as long as the building was sprinklered and had various other fire-safety systems on it."
The council has engaged an independent fire engineer to examine ACP buildings, consent documents, evaluate occupants' safety, identify any action needed and work with the Fire Service.
Tim Rainey, a lawyer acting for owners of Orewa's Nautilus, acknowledges it has ACP cladding "similar to the cladding that has proven to be an issue overseas".
But it's not a fire risk, he says, "because of the particular design of the building. The replacement cladding which is being used in the repair is different and does not have those issues. So the Nautilus is not currently a problem, nor will it be a problem when it is repaired."
Many buildings have ACP, but whether that makes them a risk is uncertain: "It is impossible to know just by looking at the building - the issue is literally contained within the aluminium panels," says Rainey.
"There is unfortunately no easy way to identify the issues. The council should have records of the products used in the construction of all buildings but until very recently changes in the type of ACP used would not have triggered the need to get an amendment to the building consent and would have potentially occurred without any record of the cladding actually used being kept.
"The issue is both a combination of the cladding and design. There is potential for legal action if the issue is identified," Rainey says.
Describing Spencer on Byron's planned recladding, general manager Greg Rimmington says the body corporate "are hopeful that the project will start early quarter two of 2018." He lists 11 existing fire-safety features including smoke detectors, sprinklers, monitoring systems, fire extinguishers and pressurised exit stairwells.
What is ACP?
Aluminium composite panel - ACP - claddings come in many forms, only some of which have highly flammable cores.
The Ministry of Business, Innovation and Employment says: "ACPs are thin sandwich-type panels made from two sheets of aluminium bound to a core of insulating material. A common use for ACPs is as external claddings on multi-level buildings as they are relatively lightweight and sturdy, while the aluminium sheets can be painted any colour."
The panels are widely used, not just for cladding, but for a variety of uses, from partitions and ceilings to billboards and mounting photographs.
Some types of ACP are made with a fire-resistant core, but others use flammable plastic between the aluminium panels. In London, the spread of the Grenfell Tower fire was blamed partly on ACP cladding with a highly flammable core.
But the presence of ACP isn't the only factor in checking a building's fire safety, says the Auckland Council's Ian McCormick.
Other factors include how much ACP cladding is used, how it is attached, whether it is broken up by non-combustible areas, and whether the building has sprinklers and other fire-safety systems.
