SCALE MODELING EXPERIMENTS ON LIMITED VENTILATION FIRE IN A TRAIN CAR WITH PARALLEL GOODS
Train cars in some railway and subway systems of the Far East including Hong Kong are always packed with luggage and parallel goods. Upon ignition of a combustible item, a limited ventilation fire will result in the train car. In this paper, train car fire under limited ventilation will be studied experimentally by a scale model. A 1/15 scale model of a train car with adjustable openings was constructed. Five ventilation scenarios including 100%, 75%, 50%, 25% and 0% of door area opened were investigated. A propanol pool fire with a large amount of fuel and a large burning area was used to represent parallel goods. The burning duration of the pool fire, air temperature, heat flux at ground level and gas concentration were measured in the experiment. Air temperature rise and flame shapes of the propanol pool fire burning under limited ventilation in the train car model were different from those of burning the pool fire in free space. When the opening area increased, the burning duration of the pool fire reduced but heat flux in the model increased. The flame shape oscillated in the train car model when burning under the ventilation scenario with a small opening area. Carbon dioxide concentration increased linearly with the decrease in oxygen concentration. When burning the pool fire in the model with all doors closed, blue flame was observed. The flame extinguished when oxygen concentration fell to 14%. The average upper layer temperature in the model was from 300°C to 500°C.