Why building owners should engage a Fire Engineer
Cladding, the Safer Buildings initiative, and why building owners should engage a Fire Engineer – Question and Answer with Omnii
What forms of cladding are at most risk of combustibility?
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 noncombustible, 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.
Is expanded polystyrene (EPS) or aluminium composite (ACP) cladding safe to use on any buildings?
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) and the type of building (e.g. one storey or 20 storeys).
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 non-combustible 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.
In addition, the type of ACP cladding that is installed to a building has a significant impact on 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 the process, where combustible elements are identified to be installed to the external façade of a building of Type A or Type B construction, a Fire Safety Engineer must undertake a risk assessment to identify whether the installed material poses a “cladding fire risk”.
How can I find out if combustible cladding is attached to a building?
There are a number of ways you can find out if combustible elements are installed to the external wall of a building. Perhaps the first step, if you are relatively familiar with building materials, is to undertake a walk-around of the building and identify the installed cladding materials to see if any combustible material if present. A good guide to typical materials that may be installed to the external wall is detailed in the Queensland Government’s “Guideline for assessing buildings with combustible cladding” (Nov, 2019) on page 36 and page 37.
Where there is any doubt, or where required by Part 4a of Building Regulation 2006, a Building Certifier, Façade Engineer, Builder or Fire Engineer could be engaged to undertake a review of the building to confirm whether combustible elements are installed to the external wall of the building. As part of the material identification process, core sampling and subsequent laboratory testing may be required.
How do I know if the cladding I am using complies with building regulations?
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.
How do Omnii Fire Engineers assess the combustibility risk of cladding?
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.
What advice do you have for building owners and body corporates to manage combustible cladding?
In Queensland, the best advice for building owners and Body Corporates to manage combustible cladding is to follow the requirements of Part 4A of the building regulation 2006.
This means that as of 31st 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 3rd 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 QBCC as a priority, as fines may be imposed.
By following the aforementioned process, a Building Fire Safety Risk Assessment will be prepared by a 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.
What steps can be taken to reduce building fire risks?
When it comes to the fire safety risk around cladding, the measures required are dependent on the outcome of a fire risk assessment such as the BFSRA, and the type of the cladding installed.
Depending on the outcome of the fire risk assessment, risk mitigation measures can include protective measures such as the strategic removal of cladding (e.g. away from fire exits) or preventative measures such as a reduction of ignition likely by removing ignition or fuel sources away from the external cladding.
As per usual, it is strongly recommended that best practice is followed with respect to the servicing and maintenance of installed fire safety features (e.g. detection and alarm system, fire sprinkler system).
Omnii has assembled a dedicated cladding team, specifically to guide clients through the cladding minefield.
With no Federal Government position on the reform of the use of Aluminium Composite Panel (ACP), each state/ territory has its own unique and complex legislation. Led by an admitted lawyer with six years practicing experience, Omnii has assembled a dedicated cladding team to navigate the best pathways toward rectification for our clients.
Through Omnii’s bespoke approach, we develop fire engineered performance solutions with the objective to:
- Reduce disruption to building operations
- Mitigate potential building works
- Minimise any rectification costs