Flammable cladding or facades have been of particular concern within Australia in the last few years due to a number of significant building fires throughout the country.
The phrase cladding is used fairly often, it simply refers to the outside skin of a building. It is most commonly used to provide thermal insulation and weather resistance as well as improving the appearance of buildings (2).
There are countless types of cladding available for buildings however, the two most common types of combustible cladding that can post a risk are;
- Aluminium Composite Panels (ACP)
- Expanded polystyrene (EPS)
These materials are both of significant concern as they are highly flammable, and due to their composition they can often increase the rate at which a fire can spread throughout a building (2).
ACP typically consists of a polymer layer sandwiched between two aluminium panels. The type of polymer can vary significantly from the most flammable (e.g. Polyethylene) through to less flammable polymers (and additional fillers / performance treatments).
EPS is a lightweight cellular plastic material which consists of hollow spherical balls. These balls are typically polystryene and may contain a number of other additives for performance (3).
Whilst these materials may have very useful and desirable properties, the concern is their specification has been inappropriate in some buildings. An example is the specification of these materials within multi-story buildings with insufficient risk mitigation (e.g. fire suppression systems).
One other concern is how commonly the material has been switched with other material. As there are so many different types of ACP, it can be difficult to determine which type is flammable and which is not, furthermore a building may contain multiple types of ACP which have been substituted and as such the documentation no longer reflects the type of cladding reported to be installed on the building.
In response, the Insurance Council of Australia (ICA), in addition with Industry partners (including CETEC – the company I work for) developed the ICA Aluminium Composite Panel and other Combistable Facade Materials, Residual Hazard Identification/Reporting Protocol.
This protocol provides a methadology (1) for scientifically assessing the type of material and conducting a risk assessment and includes;
- Identification and assessment of the composition of the core;
- Class A = 30 – 100% Organic Polymer and 0 – 70% Inert,
- Class B = 8 – 29% Organic Polymer and 71 – 92% Inert,
- Class C = 1 – 7% Organic Polymer and 93 – 99% Inert and
- Class D includes materials with 0% organic polymer and 100% inert filler)
- Evaluating the Exposure of the building and occupants based on the class above.
- Presenting remedial options for the building to consider.
Different labs present different options and whilst this information will not go into all the techniques and methodologies this can include;
- Cladding Combustabilty
- Cladding Flammability
- Cladding Identification
- Cladding Composition
This area is of course far more complicated that than, but it does give you a brief idea of why cladding is of concern, and how it can be graded.
For those that are interested, the University of Queensland, Australia have a cladding material library which is available at https://claddingmaterialslibrary.com.au/
References & Attribution
NB: Combustible and flammable have been used interchangeably however, this is not strictly true. Flammability determines how easily something ignites under normal atmospheric conditions, whilst combustibility determines how well an item burns under elevated conditions.