Combustible Cladding: What Building Owners Need to Know in Queensland

Under the Queensland Government’s Safer Buildings program, if you are the owner of a building that may contain potentially combustible cladding, you will need to engage a Registered Professional Engineer of Queensland (RPEQ) registered in Fire or Fire Safety engineering to complete the building fire safety risk assessment, fire engineer statement and the combustible cladding checklist.

To help building owners, RPEQ Andrew Brennan answers some frequently asked questions about cladding.

Q. What forms of cladding are at most risk of combustibility?

A. There are various types of cladding that are installed to the external façade of a building. While it may be obvious that some cladding types are combustible from visual review alone (i.e. timber panelling), other forms such as composite panels are more difficult to ascertain.

Composite panels such as Insulated Sandwich Panels (ISPs) and Aluminium Composite Panels (ACPs) typically contain external skins (e.g. aluminium or steel) that are deemed non-combustible in terms of the National Construction Code (NCC) fixed around an internal core. While, in some cases the core material can be noncombustible, in many cases, the core material contains combustible material.

Another form of cladding that is common in low-rise residential construction, is rendered Expanded Polystyrene (EPS). In this system, the EPS is typically fixed to the external stud wall during construction and is subsequently rendered over with a concrete-based render therefore hiding the EPS foam core from view.

Q. Is expanded polystyrene (EPS) or aluminium composite (ACP) cladding safe to use on any buildings?

A. The safe use of combustible external cladding (e.g. EPS or ACPs) depends on the extent of material (e.g. sign or full façade), the type of the material (e.g. 100% polyethylene [PE] or 10% PE with 90% fire-retardant), the type of building (e.g. one storey or 20 storey).

Where fire spread via the façade is not a primary issue (e.g. a small single storey structure), the presence of combustible cladding material may not pose a significant fire safety risk to the building’s occupants.

This is consistent with NCC 2019 requirements whereby buildings of Type A or Type B construction (e.g. two (2) storeys or more for residential buildings) must have a noncombustible façade.

However, where buildings inherently rely on the restriction of fire spread between levels (e.g. a multi-storey building), the presence of combustible cladding can pose a safety risk to occupants due to the potential for rapid fire spread and production of flaming droplets.

Additionally, the type of ACP cladding that is installed to a building has a significant impact of the potential for fire spread and corresponding impact on occupant life safety. While ACPs containing a 100% polyethylene core are highly combustible, ACPs containing a core consisting primarily of inert fillers, fire-retardants and low levels of polyethylene/polymer binder are unlikely to result in fire propagating beyond the fire source.

However, when assessing the potential for fire spread consideration needs to be given to the complete wall make up, not just the ACP, to gain a full understanding for the potential for fire spread. This assessment should only be carried out by a competent person.

To identify existing buildings where external cladding and associated external wall components have the potential to pose a safety risk, the Queensland Government introduced Part 4A of the Building Regulation 2006. As part of process, where combustible elements are identified to be installed to the external façade of a building of Type A or Type B construction, a registered fire engineer must undertake a risk assessment to identify whether the installed material poses a “cladding fire risk”.

Q. How do I know if the cladding I am using complies with building regulations?

A. In accordance with NCC 2019 Deemed-to-Satisfy (DTS) requirements, for a building of Type A or Type B construction (refer Clause C1.1 and/or Clause 2.3 for definitions), the external wall of the building must be either non-combustible material or be a material permitted under NCC DTS Clause C1.9(e).

Once the material installed to an external façade of a building has been confirmed, a review of the installed material can be undertaken in accordance to the NCC DTS requirements listed above.

Alternatively, a building certifier can be engaged to review the elements installed to the external wall of a building and provide an assessment of their compliance with the NCC DTS requirements.

Q. How do fire engineers assess the combustibility risk of cladding?

A. Once the type of material installed to the external façade is confirmed, an assessment of the cladding fire performance can be undertaken based on the product’s existing fire test data (where applicable), from a pre-existing

cladding database (i.e. the University of Queensland’s Cladding Material Library) or detailed fire testing can be undertaken (i.e. where no existing information is available).

In conjunction to understanding the cladding’s fire performance, a review of the existing building will be undertaken to better understand how the building operates in a fire and to identify the key assumptions within the building’s fire safety strategy.

Once both the fire performance of the cladding, and the building’s existing fire safety strategy is clearly understood, an assessment of the cladding fire risk can be undertaken by investigating whether installed cladding has the potential to impact on the existing fire safety strategy (e.g. spread fire between levels or produce flaming debris above an exit).

Initially, this assessment may be undertaken at a high level within the Building Fire Safety Risk Assessment (i.e. in accordance with the Part 4A of Building Regulation 2006) to identify the critical risk of the cladding; however, it can be undertaken at a much more detailed and technical perspective, to include both fire and egress modelling.

Q. What advice do you have for building owners and body corporates to manage combustible cladding?

A. In Queensland, the best advice is to follow the requirements of Part 4A of the Building Regulation 2006.

This means, as of 31 October 2019, if your building has combustible material on the facade, you must have engaged a registered fire engineer to complete a Building Fire Safety Risk Assessment by 3 May 2021. If you haven’t engaged a registered fire engineer or are unsure if you should be in the assessment system you need to contact the Queensland Building and Construction Commission as a priority, as fines may be imposed.

By following the aforementioned process, a Building Fire Safety Risk Assessment will be prepared by a registered fire engineer which will identify if your building has a cladding fire safety risk or not. Where identified to have a cladding fire safety risk, likely building works and risk mitigation measures may be required to assist you to manage the building’s risk.