London fire: Could it happen in NZ?

After the devastating speed of the fire that tore through the Grenfell apartment block in London, suspicion is growing about the building's cladding and sprinkler system.

The tower had a new aluminium composite (ACP) cladding. ACP has recently been blamed for a number of building fires around the world, including the 2015 Docklands apartment blaze in Melbourne.

ACP is used in New Zealand, but in different forms - some 'fire rated' and some 'non-fire rated'.

So could a similar situation happen with a building in New Zealand?

After the Melbourne Docklands fire, the New Zealand Government changed the law so buildings taller than seven metres must now have a fire test on their cladding.

Society of Fire Protection Engineers vice president Michael James says it means ACP cladding with a polyethylene core would not be used on buildings taller than seven metres now.

He says there are older tall buildings in New Zealand potentially with ACP on the exterior, but there would be many other measures, like sprinklers, to keep a fire like that of London's Grenfell fire from happening.

He says the key message for apartment residents if they have concerns is they should contact a fire engineer.

Construction company Thermosash says on its website it uses fire-rated ACP on external building facades, as other ACP cladding cannot sustain fire.

"It is our opinion that despite the non-fire rated version being allowed to be used for external cladding - it is not appropriate and NZ codes should be changed to reflect this," the website says.

The Ministry of Building, Innovation and Employment says: "In 2014/2015 several high-profile fires in Melbourne and Dubai highlighted the risk of combustible external cladding material on high-rise buildings."

"Although these buildings were all fully sprinkler protected, fires that started on the outside of the building were responsible for rapid fire spread over several storeys."

New Zealand fire sprinkler rules

In New Zealand, all buildings that aren't single residential dwellings must have a compliance schedule and annual building warrant of fitness, if the building has safety features like sprinklers.

Argus Fire Protection managing director Jacqui Bensemann says the New Zealand Building Code stipulates what protections a building should have, depending on its purpose.

To comply, developers must get a fire report, written by fire engineer, who makes a ruling on what type of "suppression system" (sprinklers or other measures) the building should have.

An MBIE spokesperson says New Zealand "uses a combination of active and passive fire systems, which means each apartment in a building classified as a high rise acts as an individual fire compartment, designed to contain the spread of fire".

"New Zealand also requires sprinkler systems throughout the building, plus early detection from smoke alarms. In the case of evacuation buildings are required to have a minimum of two stairs for high-rise buildings."

New Zealand's building reputation

"The Building Code is designed around people protection, which is quite different from parts of the rest of the world," she says.

Ms Bensemann says colleagues who have worked overseas in countries like the UK have found New Zealand's regulations more comprehensive, and a key part of it is having independent safety inspections.