In a typical compartment fire, fuel is present through compartment contents such as furnishings. Traditional compartments constructed from non-combustible materials will achieve burnout after the compartment contents have been consumed. In compartments with combustible construction, such as cross-laminated timber, the combustible linings will ignite, and under certain conditions, may continue to burn long after the compartment contents have been consumed, creating an additional fire risk. 

This risk can be quantified through testing for conditions under which sustained burning will occur on multiple scales. This project has utilised bench-scale experimentation in the FPA to determine fundamental material parameters necessary to achieve auto-extinction. A heat transfer-based analytical approach has been developed in parallel to predict the burning behaviour based on well-defined boundary conditions.

Subsequent full-scale experiments undertaken in the BRE burn hall have demonstrated that this approach is valid for predicting auto-extinction of exposed cross-laminated timber surfaces within a compartment. Data from these experiments also allow exploration of charring rates of engineered timber in “real” fires, and subsequent consequences for load-bearing capacity; changes in compartment fire dynamics due to combustible linings; and the impact of external fire spread to adjacent structures. Alastair Bartlett’s PhD is supported by Arup and EPSRC through CASE Studentship 14220013, with generous additional funding for the full-scale compartment fire experiments from Arup.