Fire resistance of external light gauge steel framed walls clad with autoclaved aerated concrete panels

Abstract

This paper presents an investigation into the fire resistance of external light gauge steel framed (LSF) walls clad with autoclaved aerated concrete (AAC) panels exposed to fire on the external side. Past research has been limited to the fire resistance of internal LSF walls clad with gypsum plasterboard on both sides. A series of experimental studies including thermal material property tests, a full-scale (3 m × 3 m) ambient capacity test of LSF wall and full-scale standard fire tests of non-load bearing and load bearing LSF walls were conducted to investigate the fire resistance of external LSF walls clad with AAC panels. Finally, a small-scale (1.2 m × 1.2 m) fire test of a wall made of AAC panels was also conducted to investigate the performance of joints between AAC panels. AAC panels with very low thermal conductivity performed exceptionally well by keeping the temperatures low for 160 min achieving a fire resistance level (FRL) of 204 min in load bearing conditions and 240 min in non-load bearing conditions. Hence, LSF walls clad with AAC panels can be used when higher FRLs are required. Experimental studies such as these on the whole system enable a good understanding of the overall fire performance of external wall systems in terms of structural adequacy and integrity instead of focusing only on the cladding.