MCG QUANTITY SURVEYORS BLOG
Aluminium Composite Cladding being used in Victoria
So on the ABC News website on the 16th July 2019, the headlines read “Flammable Cladding to be stripped from buildings under Victorian Government Plan”.
It was the words of the state political reporter Richard Willingham that echoed the announcement of the Victorian Premier Daniel Andrews plan to announce the $600 million package to fund the rectification works. How do they intend to fund this? well the plan is that $300 million will be funded directly from the state coffers. With the remaining half to be sought from the Commonwealth.
With some 500 buildings in Victoria requiring rectification works to be made safe, Canberra has responded to the call from the Victorian Government with a very clear ‘No’. Treasurer Josh Frydenburg stating that this problem was a state issue and that the Federal Government “Will not pick up the bill”.
In addition to the treasurer’s statement, when federal Industry Minister Karen Andrews was asked if Canberra would make a contribution. Ms. Andrews’s response was “The Commonwealth is not an ATM for the states. So no, this problem is of the state’s making and they need to step up and fix the problem and dig into their own pockets,”.
The contingency from the Victorian Governments plan is to fund this shortfall via the way of increasing the building permit levies. The increased levies at this stage are to be sought from developments in excess of $800,000.
Regardless of the funnels that the funds will be sought, the question that requires an answer is a simple one. “What is the forecast cost of the rectification works? Is $600 million enough?”
Well, consumer advocate Anne Paten from the Victorian Building action believes the real cost was in the order of many, many billions.
Although the Victorian Government has announced a plan for 500 buildings, it seems that many buildings with rectification work required, will simply just miss out.
As of July 5th, the taskforce audit inspected 2,227 buildings and noted that:
- 72 x rated extreme risk
- 409 x rated high risk
- 388 x rated moderate risk
By my calculations, that totals 869 buildings at moderate risk and above as at the 5th July 2019.
So even the Victorian Government by its own omissions are prepared to leave some 369 buildings untouched, without rectification.
In just the past fortnight, MCG Quantity Surveyors have been requested to provide costs to rectify, remove and replace at risk claddings from developments across Melbourne.
Albeit the total m2 of cladding that has been required to be rectified, removed and replaced varies, it is the avg cost of this replacement that is important to us.
In my opinion, the cost of the rectification of the buildings at risk within Victoria alone is in line with the opinions expressed by consumer advocate Anne Paten from the Victorian Building action, “many, many billions”.
As you can clearly see from the table below, just the average of the last 4 developments indicate an average cost of $513.27 per square metre of product removed.
This is a real concern, especially given the Victorian Governments current announcement of only funding 500 developments at risk.
In June 2017, it took 90 minutes for fire to race up 20 storeys within the Grenfell Tower, killing 72 people.
Grenfell Tower was covered in an Aluminium Composite Cladding.
This type of cladding consists of a layer of plastic sandwiched between two aluminum sheets.
The internal layer of the sandwich panel is usually made up of polyethylene (also called polyethylene). It is a high-density polyethylene or HDPE.
Dr. Kate Nguyen, who leads a fire and facade engineering group at RMIT University, explained the issue with the HDPE product is its “combustibility ratio”.
The ratio is calculated by dividing the amount of heat released from burning material by the amount of heat needed to ignite it. The higher the number, the more flammable the material.
To put this into perspective, if you had a house that was clad in Red oak, for instance, is pretty low: it has a combustibility ratio of 3.
However, at the other end of the scale is HDPE. Dr Nguyen states “The combustibility ratio of HDPE is 25.” The scary thing to note here is that HDPE, therefore, produces 25 times more heat than it takes to combust.
So why does fire spread so quickly when a building is clad in an Aluminium Composite Cladding?
Well, when the HDPE is on fire, “the solid plastic turns to liquid, so when HDPE melts, it will drip down.” Says Dr. Nguyen.
Not helping the issue is that aluminum is an excellent conductor of heat. So if the aluminum gets hot enough, it will transfer that heat into the HDPE underneath.
As any firefighter will tell you, fire LOVES oxygen. Oxygen will accelerate the combustion of materials when alight.
Given that the aluminum composite cladding is fixed to the external of these building by way of a steel furring channel, or ‘top hat’ section, this construction technique provided a cavity behind the cladding and the internal framework of the building.
“These cavities funnel heat and smoke up the outside of a building “like a chimney”, Dr Nguyen said.
So a fire starting within aluminum composite cladding on any given floor of a building can spread in all directions, FAST.
- Upwards due to the flames and smoke in cavities;
- Downwards due to liquid HDPE ignites more HDPE as it drips down; and
- Sideways, as the aluminum spreads and transfers the heat.
Marty Sadlier is a founding director of MCG Quantity Surveyors and a member of the Royal Institute of Chartered Surveyors (RICS). Marty’s advice is regularly sought as an accredited expert witness and he sits on the interview panel for the Australian Institute of Quantity Surveyors (AIQS).