Four types of cladding products have been found to be safe and have been endorsed by an independent panel for use in a major cladding rectification program in New South Wales.
In its first report, the New South Wales Cladding Product Safety Panel (CPSP) has endorsed four types of products for use under the state’s Project Remediate strategy through which combustible cladding on 214 high-risk residential buildings is being remediated.
- solid aluminium
- solid metal sheets
- fibre cement
- non-combustible cement render.
Released by NSW Minister for Better Regulation Kevin Anderson, the report is the first issued by the CPSP, which was established as an expert panel to support the Cladding Taskforce and to advise the government on suitable products and systems to remediate combustible cladding.
Its advice will inform work being carried out under the government’s three-year Project Remediate Program.
Announced last year, that program will assist owners of 214 residential buildings which have been identified as having high-risk combustible cladding by enabling them to access interest-free loans to pay for cladding removal along with project management and guidance services to help with the remediation process.
In its report, the panel recommended the replacement of all composite panels which have 8 percent or more combustible material by mass in its core.
Panels which contain combustible material representing less than or equal to eight percent by mass may be able to be retained under a performance solution provided they meet the NCC Verification Method CV3, it said.
On specific products, the list represents the first tranche of those which the panel has endorsed for use on the program.
The first is solid aluminium.
Solid aluminium products are typically a flat sheet of aluminium, often 3mm thick, with an applied paint coating. The sheets are typically cut to size and the edges can be folded to allow mechanical (non-combustible) fixing.
Where they are installed as part of a suitable external wall system, the panel says that these products are low risk, are NCC compliant and are generally known to pass the AS 1530.1 test for combustibility.
Whilst some have suggested that solid aluminium panels spread fire in a manner comparable to combustible composite panels, the CPSP says such suggestions are wrong.
Unlike composite panels containing polymeric materials such as polyethylene which have low combustion temperatures, solid aluminium panels have high melt and combustion temperatures and will not spread flame in a building fire or contribute to rapid fire spread as seen in the Lacrosse and Grenfell Tower fires.
This is important as primary objective of non-combustibility requirements in the NCC is to prevent the spread of fire between compartments of buildings, i.e. between units or vertically between storeys.
To be sure, the panel acknowledges that there are risks involved.
Any gaps behind the aluminium may increase flame projection, it said.
Meanwhile, there is a chance that aluminium panels – like those made of many other types of material – can fall away from the building in a fire where they are not suitably attached.
On the first issue, it says this can be addressed through suitable cavity barriers which form part of design requirements under the project.
On the latter, it says this can be addressed through mechanical fixing which is specified under the panel’s guidance on cladding system design.
Next, there are solid metal sheets.
These are typically steel-based, solid metal sheets. They have high melting and combustion temperatures.
As with solid aluminium, the panel says solid metal sheets are a low risk and compliant product when installed as part of a suitable external wall system.
Since metal sheeting products come in many shapes and forms with varied fixing requirements and coatings, it is necessary for each manufacturer to provide evidence that their product(s) comply with all relevant provisions of the NCC.
Third, there are fibre cement sheets, which are compliant when installed as part of an external wall.
They may be used wherever a non-combustible material is required as per clause C1.9 of the BCA.
As with all cladding products, fibre cements sheets need to be considered as part of the whole cladding system.
Whilst they contain a small amount of combustible organic fibre which is coated with the cement, the panel noted that these products perform well in fire tests and that their use in New South Wales has been allowed under the NCC and previous building codes for forty-five years.
Finally, there is non-combustible cement render.
This may deliver a simple, cost effective and/or practical solution in cases where there is insufficient space for replacement cladding systems to be installed or where the current combustible cladding product is performing an aesthetic function only.
When using these products, the panel notes three points of caution.
First, it is still important to ensure that the full external wall systems still meet the Deemed to Satisfy (DTS) provisions under the NCC for fire safety. To do this, each cladding product and system must comply with the fire resistance tests under Australian Standard AS1530.1 apart from where a combustible product can be used,
Next, cavity barriers should be installed in locations where there are gaps behind cladding systems that could form a path for fire spread.
These include spaces such as around windows, doors and other openings; at horizontal slab edges between storeys; and vertically where internal bounding walls (fire rated) between sole occupancy units and/or between sole occupancy units and common areas meet the façade.
Finally, mechanical fixing manufactured from fire-proof materials for external wall panels is required.
Where panels are fixed to by simple tape or adhesive, the CPSP notes that there is a risk of large pieces of debris falling off the building in a fire as these materials often soften at temperatures of below 120 degrees Celsius.
By contrast, fire-proof mechanical fixings are not subject to failure at these temperatures.
The panel also notes that cladding replacement systems need to be designed for each building by suitably qualified professionals.
In addition to fire safety, such design will need to account for structure including wind loading, weatherproofing, condensation, thermal performance/energy efficiency, durability, acoustics and aesthetics.
As stated above, the aforementioned products represent the initial tranche of those which have been endorsed for use under the program.
The panel is continuing its assessments with a view to including any additional replacement cladding systems that are proven to be suitable in later tranches of endorsed products and systems.
Potentially, these could include either bonded laminate products or composite panels with a core comprised of less than 8% combustible material by mass capable in external wall systems that meet verification method CV3.
Anderson welcomed the report’s release.
“Thanks to our panel of experts we’ve now identified four, safe, options that can be specified for use as part of the Government’s replacement program,” he said in a statement.
“We are taking the lowest possible risk approach to fire safety. That’s why every component we are recommending in the first tranche will have to meet the highest fire safety standard under the Building Code of Australia (now known as the National Construction Code).”
CPSP Chair Professor, Mark Hoffman said the panel would be give further consideration to additional products and systems after more rigorous independent testing is completed and demonstrated.
“There may be additional systems that can safely include elements with some combustibility,” he said.
“The panel will consider submissions relating to these but to date, we have not been provided with robust data from independent accredited labs which tests both the product and the system.”
Assessment and project design for the first batch of 30 buildings to be remediated under the program is expected to commence by July this year.
Following this, the first cladding is expected to be removed later in the year.