Experimental investigation of ventilation effects on charring in combustible compartments

The increasing use of mass timber in modern construction presents unique challenges for fire safety, as timber contributes additional fuel during fire events. However, the understanding of fire dynamics in combustible compartments remains limited, with relatively few experimental studies available. This paper presents an experimental investigation of seven cuboid compartments (1.2 m × 1.2 m × 2.4 m) to examine charring behaviour under varying orientations (horizontal and vertical) and ventilation conditions. Thermal data were further compared with eight additional experiments that varied in opening configurations. Charred samples were collected from all six surfaces of the compartments and analysed to quantify mass loss due to charring. Results show that charring depth is strongly influenced by the size and location of the openings, while vertical compartments present substantially higher heat release rates compared to horizontal ones under the same opening conditions. The findings reported in this paper provide new insights into fire behaviour in combustible compartments, with implications for the fire safety of combustible construction. • Experimental study of fire dynamics in fully combustible compartments • Charring measurements at multiple locations in combustible compartments • Impact of ventilation conditions on fire dynamics in compartments • Influence of opening configuration on compartment fire behaviour