Fire Safety Science Digital Archive

Under-ventilated enclosed fires are recognized to be important scenarios, owing to their potential risks. They occur with ventilation, natural or mechanic, providing too small amount of oxygen or over production of combustible gazes in the fire zone. A full scale test has been performed using wood pallet fire. The test rig is built with marine containers. It allows fire growth in a room and smoke spread in other connected compartments. The experimental set up provides source mass loss rate, temperatures close to the fire and in the smoke flows. Fire growth and smoke spread is detailed and analyzed. It is shown that, after an ignition period, oxygen depletion is strong in the fire room and under-ventilated combustion occurs, and the temperatures begin to increase continuously everywhere in the compartments and in the smoke plume at the exit. Measured temperatures are presented and analyzed. CFD modelisation of the fire growth has been performed with specified Heat Release Rate (HRR) or with a simplified pyrolysis mechanism with one step. The sequence of the events, which have been observed inside the compartments during the test, are also well reproduced with the CFD results. However, the comparison between calculated and observed temperatures highlights the difficulties to calculate the accurate Heat Realease Rate (HRR), its kinetic of growth and the maximum value, when the fire is in the under-ventilated regime.