Another major fire risk has been uncovered in Melbourne – curtain walls containing flammable aluminium composite cladding (ACP).

At least 10 residential buildings in Melbourne have a type of curtain wall with flammable cladding concealed within the wall cavity, according to a report by a high-profile fire safety consulting firm. Exterior Glass Curtain Wall

A curtain wall is a window system positioned externally to the building structure, spanning multiple levels and forming a continuous facade.

This curtain wall fire risk is a late discovery, outside the original scope of Cladding Safety Victoria (CSV). Affected apartment owners are facing insuperable remediation bills in the tens of millions and sometimes more than $100 million.

We Live Here has seen a copy of the alarming fire expert report, entitled Preliminary Overview of Melbourne City Buildings with Non-Compliant Curtain Walls. At the date of going to press, the report is yet to be released. When released, we expect it should set off alarm bells for the state government.

The consultants’ report was triggered by the discovery of a staggering quantity of cladding in a curtain wall of an inner-city Melbourne apartment building. Previous investigations by others had failed to discover much of the cladding concealed in the curtain wall.

The consultants found the vertically connected curtain wall system posed an credible risk of rapid fire spread over multiple storeys.

Including the additional flammable material uncovered, the total area of flammable cladding in the building is an astonishing 50,000 square metres. This Melbourne building now holds the unenviable record for the largest cladding project in Australia – easily surpassing the previous record held by a Perth building with 28,000 square metres.

The consultants have warned the owners that the issue is serious:

“With the building in its current state, [this firm] is of the opinion that the City of Melbourne’s initial evaluation that the building is a danger to the life, safety or health to members of the public and to any person using the building or to any property; is indeed correct.”

Extending their research, the consultants found several other high-rise buildings in the Melbourne CBD fitted with the same curtain wall system from the same overseas manufacturer.

On top of this, the report found that there were several ignition risks within these high-rise buildings that could create fires.

The research by the fire risk consultants includes findings that the extensive presence of ACP within the curtain wall cavity can lead to broken sheet glass falling in the event of a fire.

In contrast, most other windows installed on Melbourne high-rises are fire resistant. In a fire, the outer layer of glass in non-curtain windows will break up into very small pieces and fall. The peculiar construction of the curtain wall, with flammable material immediately behind glass, is prone to make the glass crack and fall in larger pieces.

How has this issue gone undetected, or at least unreported? The fire consultants explain it may be a case of “out of sight, out of mind”. The ACP panels within these buildings’ curtain wall cavities are not visually identifiable from outside the buildings. To see the flammable material, you need to undertake “destructive investigation of the external wall system or internal wall linings.”

The expert report paints a disturbing picture for the owners of the building that initiated the study:

“Twenty-six insurers have been approached and denied insurance for the building. A full replacement cost could be in vicinity of $150 million.”

“Once the insurers know the full extent of the cladding there is simply no way they will provide cover.”

And we all know that you need insurance to get a loan. With the building unable to source insurance, owners are unable to obtain any funding for remediation works. The owners also risk a fine of $462,000 if they do not remove the flammable material to satisfy the building order that has been issued by the council.

The consultants cite engineers and scientists around the world who have been studying the curtain wall fire risk issue for some time now.

A paper published in the Architecture and Planning Journal in 2018 analysed how fire spreads in curtain wall facades. The study by Mostafi Elehefnawi was able to demonstrate the behaviour of fire spreading in the gap between a curtain wall and floor structure slab. A further danger was found to arise from secondary fires ignited by burning debris falling from the upper floor levels.

The report also cites a 2020 Australian study by the CSIRO that examined a series of fire incidents involving ACP. For example, the Wooshin Golden Suites apartment building in South Korea was a building that was affected by a combustible curtain wall system. A fire at the building in 2010 started from a spark in an electrical outlet on the fourth floor. Within 20 minutes the fire spread up the vertical facade to the top floor of the 38-storey building. The vertical fire spread was around one of the building’s exterior alcoves. The resultant re-radiation and chimney effect appeared to enhance the fire spread. The fire brigade deployed helicopters to drop water on the building and to evacuate some occupants from the roof. While thankfully there were no fatalities, several people were seriously injured.

So, it appears that a huge, invisible fire risk that has long concerned experts here and overseas is only now being becoming known to the general public.

The consultants conclude their latest report with a statement addressing the role of the state government regarding the several buildings’ flammable curtain walls:

“Whilst external wall cladding continues to be rectified, it is of our belief that equal importance should be apportioned to curtain wall systems and their use in high-rise buildings to ensure the safety of dwellings and life. Government intervention will be required to help the owners’ corporations deal with the financial burden this will place on the buildings.”

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