CASE STUDY: Combustible Cladding Risk Assessment

Overview – Building

• Mixed – use building in Sydney, Australia
• Class 2 (apartments), 7 (carpark) and 6 (retail)
• Type A Construction
• Five storeys
• Existing Fire Engineering Solution

Problem

• Fire Safety Order issued by local Council requesting an audit to identify any risks associated with the cladding and the scope of works to mitigate the risk.
• The quotation received to replace all external cladding exceeded $AU 5,000,000.

Solution

To identify risks associated with a cladding system, the product and system used need to be identified. In most cases, the information on the product installed is not readily available and is difficult to obtain.

Our first act of action is to contact the original architect, builder or developer, where possible. This helps us to take the right direction in terms of identifying the product supplier and installer. Only if the desktop investigation does not yield satisfactory results, we initiate testing of the product. In the given case, we were lucky to find out that the product that was meant to be installed was Alucobond Plus. We contacted the original product supplier, who was able to produce invoices, purchase orders and delivery confirmations confirming that the product supplied to site was Alucobond Plus, which is a fire-grade product.

The next challenge was to identify the fixing method. To limit the extent of damage to the external skin of the building, the product supplier was invited to attend site and conduct an inspection of the cladding installation, to confirming the product installation method. This was completed within a day and the only “damage” to the cladding was the removal of a sealant section installed between Aluminium Composite Panels (ACPs).

We noted all the locations of ACPs, and our fire engineers performed a risk assessment using two separate methods. The first method being the Risk Assessment Tool developed by the Victorian Building Authority (VBA) and the second, the in-house developed risk matrix applying façade design principles outlined within the Society of Fire Safety Practice Guide on Facades/External Wall Fire Safety Design. The first method returned the risk ranking as “low”, whereas the second method, as “moderate”, meaning that some minor physical works needed to take place to bring the risk rating down to “low”.

The risk assessment report was successfully presented to Council, who consulted an independent fire safety engineer requesting a review or our report and consequently supported the proposed solutions.

Conclusion

This is one example of a successfully performed risk assessment. It not only demonstrated that the external building cladding on the subject project presents a low risk to life and safety of the occupants and fire brigade personnel, but also saved the apartment owners in the order of $5,000,000 – the price that was quoted for the full removal and replacement of the cladding panels.