Summary
The article discusses the issue of combustible cladding on the external façade of buildings, which has become a major safety concern since the Grenfell Tower fire in 2017. The article explains what cladding is and why some types of cladding are so flammable. It highlights the fact that the majority of cladding systems used in the construction of buildings comprise non-combustible elements, such as masonry, stone, fibre cement, glass, and solid aluminium. However, contemporary building design has seen the extensive use of Aluminium Composite Panels (ACPs), which are a composite product consisting of an external Aluminium face with a highly combustible/flammable core comprising Polyethylene (PE).
The article also discusses the NSW Cladding Taskforce (NSWCT), which was established to identify buildings with potentially combustible cladding and support local councils to address the use of non-compliant cladding materials. It further explains the NSW government's endorsement of a rectification scheme known as Project Remediate, which is a three-year program to help rectify combustible cladding on high-risk Class 2 residential buildings identified by the NSWCT. Finally, this article also raises a red-flag regarding the fact that currently, only Type A and Type B buildings are required to have a non-combustible façade or external wall, and that buildings of Type C construction and Class 1 dwellings/houses are permitted to be constructed with highly flammable cladding.
Background
During the early hours of 14 June 2017 in West London, in a building known as the Grenfell Tower, a fire broke out in the kitchen on the fourth floor of the 23-storey building which subsequently spread rapidly up the exterior façade of the building, as can be seen from Figure 1. The fire only burnt itself out 24 hours later and as the tragedy unfolded claimed seventy-two lives, ravaging the entire building, as shown in Figure 2. Closer to home, a cigarette butt in a plastic container was enough to ignite the external façade of Melbourne’s Lacrosse tower, around three years earlier. What was particularly alarming was that once a small section of the external façade caught fire, it took only 11 minutes for the fire to travel up the side of the building! Fortunately, four hundred people were safely evacuated with no fatalities. However, there was significant building damage.
Figure 1. Grenfell Tower fire at 4:43 AM showing fire brigade intervention (Courtesy of Google Images)
Figure 2. The inside of an apartment in Grenfell Tower after the fire (Picture - UK Met Police)
The cause? Combustible cladding or composite metal panels with polyethylene cores.
The Lacrosse building fire and the subsequent 2015 incident report instigated changes within the Australian building industry with a view to change construction practices and ban the use of combustible cladding. The Grenfell tragedy and the subsequent inquiry brought this issue into global focus. The problem however remained that there were a large number of buildings constructed using combustible cladding on the external façade – disasters waiting to happen; a risk which was far from acceptable. The New South Wales Government in Australia has been addressing the issue of combustible cladding on apartment buildings via a voluntary opt-in program to help remove combustible cladding on an estimated 225 buildings. Cladding rectification works for existing building stock has been a major undertaking in New South Wales, Australia over the last few years.
What is Cladding and why is it so flammable?
Cladding is a building product such as a type of board, sheet, panel, or cover that is installed on the façade of a building to create a barrier between the exterior of the building and the interior. Cladding serves several functions including:
- Improved building aesthetics
- Weather and water seal from external conditions
- Improved thermal and acoustic insulation ratings
Contrary to widespread belief, most cladding systems used in the construction of buildings primarily comprised non-combustible elements, such as masonry, stone, fibre cement, glass and solid aluminium. However, contemporary building design has seen the extensive use of Aluminium Composite Panels (ACPs), which are a composite product consisting of an external Aluminium face with a highly combustible / flammable core comprising Polyethylene (PE). This PE-based ACP is the same product used on the Grenfell Tower and the Lacrosse Building. While these panels are cheap, provide a level of insulation, weatherproofing and are aesthetically pleasing, in the event of a fire the core melts and can easily ignite. The loss of the core can also cause the façade to deform and delaminate, as shown in Figure 3. While not all composite panels are the same, those panels that are combustible remain a serious fire hazard and safety concern due to its highly flammable nature.
Figure 3. Aluminium composite panels and the associated fire risk
Cladding Remediation NSW
As a result of the fire hazards introduced through the use of combustible cladding, evidenced in building fires like the Grenfell Tower and the Lacrosse Fire, the Building Code of Australia (BCA) has undergone several major changes to address the increased concern of combustible materials on the external façade of buildings. In particular, the BCA has placed strict guidelines on having only non-combustible building materials on external walls of Type A (i.e. 3-storeys or more) and Type B (i.e. 2-storeys) residential buildings. Furthermore, this requirement was supported with the introduction of a product ban in 2018, where the Fair Trading Commissioner prohibited the use of cladding products on buildings that have more than 30% combustible content by weight.
The NSW Cladding Taskforce (NSWCT) was established in July 2017 to identify buildings with potentially combustible cladding and support local Councils to address the use of non-compliant cladding materials. NSWCT has reviewed over 4,000 buildings and identified approximately 225 buildings that are likely to require remediation. The NSW Government has also endorsed a rectification scheme known as Project Remediate led by the building company, Hansen Yuncken. Project Remediate is a three-year program to help rectify combustible cladding on high-risk Class 2 residential buildings identified by the NSWCT.
Closing Notes
Currently, the BCA only stipulates buildings that are of Type A Construction (i.e., three storeys or more) and Type B (i.e. 2 storeys) to have a non-combustible façade or external wall. This means that a Class 2 building of Type C construction (i.e., one storey) or a Class 1 dwelling/house are permitted to be approved and constructed with highly flammable cladding with no concern to the residents' safety. This is not widely known. For the average homeowners and residents, the serious safety risks involved with the use of the combustible cladding on residential buildings should be brought to their attention. Further research will be required in the coming years to determine whether more stringent restrictions are required for Type C residential buildings and single dwellings. Historically, revising legislation, standards and the building code will only occur when there is tragedy or public outcry. However, safety standards should not be written in blood and there are lessons to be learnt from history.
If you have any concerns relating to the safety of your building in relation to the external wall system used and to learn more about the Project Remediate programme, visit the NSW Government Website – Replace Flammable Cladding Through Project Remediate.