Experimental Study on the Fire Impact of Ceiling Insulation on CPVC Pipes

Fires igniting within a ceiling space often escalate into large-scale fires because of delayed detection times, rapid fire spread, and difficulties in firefighting operations. This study investigated the effect of combustible insulation materials on CPVC piping in sprinkler systems using real-scale fire experiments. Based on the top floor of an apartment, this study focused on insulation materials with the highest fire load among the combustibles in the ceiling space. A field survey and fire tests were conducted, and the experiments with EPS and XPS insulation revealed rapid flame spread and the complete destruction of the CPVC piping owing to high heat intensity. Even PIR insulation, a fire-resistant material, causes the destruction of CPVC piping located directly above the fire source. This confirms that combustible insulation materials within the ceiling have a significant negative impact on the functionality of the CPVC piping, rendering it incapable of performing its intended functions. Therefore, this study suggests alternatives for enhancing the reliability of automatic fire-suppression systems during fires in ceiling spaces.