In August 2018 a ban was imposed on the use of Aluminium Composite Panels (ACPs) with a core comprising of greater than 30% PE by mass, on all buildings greater than three storeys high [1]. This ban was imposed due to the number of recent tragedies, such as the 2014 Lacrosse building fire in Australia and the 2017 Grenfell Tower fire in London, which saw the rapid spread of fire vertically up the buildings’ external walls where ACPs had been used.
Another concern outlined in a 2018 report, was the high occurrence of inferior building products [2]. It was noted that there had been incidences of product substitution in ACPs, and as it was recommended a compulsory building product certification system be put in place in the industry, particularly for high risk products. This is where characterisation techniques are invaluable in verifying that the product specified is that which has been used on a building is important, even if a product specification sheet is provided.
ACPs consist of a core material which is sandwiched between two thin aluminium sheets. The core material content falls into one of 3 categories: 1) close to 100% PE, 2) a mixture of PE and mineral fillers, and 3) less than 3% PE [1]. Identification of the type of polymer present and mineral filler (if any) is vital, as they all act differently when exposed to heat. For example, the mineral filler aluminium hydroxide when heated above 180°C will decompose and release water, delaying ignition of the core.
In order to verify the core materials present and the percent fillers used, combinations of complimentary characterisation techniques were utilised. These include; 1) SEM equipped with EDS for Microanalysis, 2) FTIR spectroscopy, 3) XRD and 4) Thermal analysis techniques such as TGA and DSC [3, 4].