ABSTRACT

Recent large-scale open-plan testing has highlighted the rapid change in fire dynamics within the compartment following the ignition of an exposed timber ceiling. There is no standard approach, nor is there any significant research that has been undertaken to understand what impact inverting an exposed surface to a ceiling orientation has on the time to ignition and charring rates. Utilising the Fire Propagation Apparatus (FPA), a novel methodology is implemented to research these phenomena at bench-scale for an inverted orientation. When comparing the piloted ignition study for a normal orientation to that of an inverted (i.e. ceiling) orientation, inverting the sample is found to have a noticeable impact on the time to ignition of the Cross-Laminated Timber (CLT) specimens, with no clear impact on the critical heat flux of ignition, nor on the charring rates. The findings have implications for a building’s fire safety strategy that must be considered.

Keywords: Ignition; Charring Rates; CLT; Ceiling