Thermal Stability and Combustibility Characterization of Aluminium Composite Panel Core Materials

ABSTRACT Aluminium composite panels (ACPs) are widely used as facade cladding, including in aerodrome buildings, because they are lightweight, weather‐resistant and easy to fabricate. However, the combustibility of their core materials has raised serious fire safety concerns. In this study, five commercial ACP cores commonly used in Malaysia, namely limited‐combustible (A2), fire‐retardant (FR1, FR2, FR3) and polyethylene (PE), were extracted from the panels and characterized using Energy Dispersive X‐Ray Fluorescence (EDXRF), Thermogravimetric Analysis (TGA), Cone Calorimetry (CCM) at 50 kW/m 2 and Scanning Electron Microscopy (SEM). EDXRF showed that A2 was dominated by calcium (75.7%), the FR cores contained lower calcium with notable aluminium, and the inorganic fraction of PE was mainly calcium, with smaller amounts of magnesium, titanium, aluminium and sodium. TGA showed that A2 retained 63.4% residue at 800°C, the FR cores 44.9–54.2%, and PE only 8.1%, indicating almost complete decomposition. In the CCM tests, PE ignited at 18.0 ± 1.7 s and reached a peak heat release rate (pHRR) of 684.4 ± 19.8 kW/m 2 , whereas A2 ignited at 60.7 ± 13.7 s with a pHRR of only 62.3 ± 16.6 kW/m 2 . The FR cores ignited between 34.0 and 63.0 s with pHRR values of 165.6–203.9 kW/m 2 , but continued flaming longer than both A2 and PE. SEM of the residues showed that A2 remained compact and intact, FR1 left a porous, partly fragmented residue, and PE left only a fragile, powdery residue. Overall, the results show a clear ranking of A2 > FR > PE in terms of heat release, mass loss and residue, providing practical guidance for safer ACP core selection, although system‐level testing is still required for full panel assemblies.