Experimental Investigation of Flame-Spread Velocity on Solid Fuel Surfaces

This experimental investigation examined flame-spread behaviour across four solid wood specimens using measurements of specimen properties, ignition behaviour, temperature histories, flame-spread distance and mass change. The results demonstrate measurable differences in the response of the specimens despite broadly similar geometries. Flame-spread distance ranged from 0.195 to 0.250 m, while direct velocity estimates based on the consolidated distance and time data ranged from approximately 1.00 × 10-3 to 1.48 × 10-3 m/s. The results indicate that flame spread is influenced by the interaction of material properties and thermal behaviour. Density, ignition temperature, heat transfer and the spatial development of the temperature field may all contribute to the observed differences. The thermocouple histories suggest progressive heating of the specimens and demonstrate that the thermal response varies with position and time. The study also reinforces the importance of flame orientation and environmental conditions. Buoyancy can enhance upward flame spread, while airflow direction may either promote or oppose propagation. Moisture, material structure and other atmospheric conditions can further modify ignition and flame-spread behaviour. These factors are relevant to fire-safety engineering because faster flame spread can reduce the time available for occupant evacuation and increase the rate of fire growth. Overall, the findings support the use of controlled experimental testing to characterize combustible materials. However, the numerical results should be considered preliminary until the inconsistencies identified in the original dataset are resolved and the heat-transfer model is verified. Future studies should incorporate replicate tests, better characterization of material properties and environmental conditions, and high-resolution flame-front tracking to improve the reliability and generalizability of flame-spread measurements.

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