30.06.2017 : Michael Belsham and more

What's the fire safety risk of NZ multi-storey buildings?

The fire at Grenfell Tower, London has brought into focus the fire safety of multi-storey buildings worldwide, particularly with the performance of external cladding systems. Owners and occupiers of multi-storey buildings across all sectors are questioning the safety of their buildings.

The fire industry in New Zealand has been acutely aware of the fire risk of combustible cladding, following a series of similar incidents overseas since 2010 – in Melbourne, Dubai, China, Roubaix and Grozny.

We’re all asking – how safe are our buildings?

What is the chance of this happening in NZ?

We should take solace in our country’s small size, as it allows for agile and robust processes – with regularly updated building code and increased inspections for fire safety. Here, fire engineers are more involved in projects and there is increased rigour in design and checking of fire design of building and products. Effective fire engineering takes a multi-layered approach to ensure that if one fire safety system fails to correctly operate, a safe escape is still provided. The success of fire engineering is proven through the lack of high profile incidents in New Zealand.

High rise buildings in New Zealand typically have sprinklers, common fire detection systems, and multiple escape routes. They are also required to have regular checks by independent qualified persons (IQP’s) to ensure fire safety systems are operating as designed and to highlight any deficiencies that require attention.

Are all cladding panels dangerous?

The fire incidents have been found to use aluminium composite material (ACM) panels for the external cladding. ACM panels are composite cladding panels consisting of two sheets of aluminium metal with an insulating core. There are two main types of ACM panels; one with a highly combustible core (i.e. polyethylene or polyurethane), and one with fire retardant or non-combustible core (e.g. mineral wool).

The two types of ACM panels behave very differently in a fire, with the fire retardant panels designed to prevent rapid vertical fire spread. The height of a building in New Zealand will determine which ACM panel is appropriate. New Zealand has always had strict requirements for external cladding materials. For the use of ACM there has been an additional fire test requirement for nearly 20 years.

It always pays to have the building reviewed by a professional fire engineer to confirm the correct materials are used.

How can we be sure the external cladding is safe?

It can be very difficult to tell by inspection if external cladding has the correct fire requirements for the building. Cladding systems are complex and involve more than just the panels, but also the insulation material and cavities behind the panel. We recommend a fire engineer checks the building if there is compliance uncertainty. It is also important that fire engineers carry out monitoring during construction and checking the correct materials are being used to comply with the regulations.

Is this just about cladding systems?

Fire safety of any building is reliant on far more than just its cladding and requires a holistic assessment of safety. High rise buildings in New Zealand would have a multitude of systems and features that provide redundancy and reliability of a safe escape route from the building with sprinklers, fire alarm systems, multiple stairs and fire separations.

There is also an increasing focus on passive fire protection (or fire stopping) in New Zealand for fire separation between floor levels and into the escape route cores to ensure fire does not spread to critical areas of the building.

How can Beca help?

The fire engineering team at Beca regularly assist building owners, architects, and developers to minimise fire safety risk in design and monitor the appropriate selection of products and construction to ensure risk to the profession and community are minimised.

For further information please contact one of our Beca fire engineering team.

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