Vertical temperature distributions in ventilation shafts during a fire

• A model calculating temperature distributions in ventilation shafts was presented.
• Influence of ventilation on smoke temperatures was discussed.
• Validation experiments were conducted under various exhaust rates.
• The mean error between the model and the experiments was around 4.2%.

As fire smoke spreads in shafts, the affected area experiences a significant rise in temperature. Thus, calculating temperature distributions is of vital importance in understanding smoke motion in shafts during a building fire. Generally, the smoke temperature in a ventilation shaft is mainly affected in two ways: (i) heat exchange occurs between smoke flow and shaft walls, and (ii) a part of smoke is exhausted out of shafts from the top due to ventilation and another part of smoke is driven into the shaft from the bottom. However, these factors were usually ignored or partly considered in previous studies. This paper presents a mathematical model for predicting vertical temperature distributions in ventilation shafts. In this model, the influence of both shaft walls and ventilation is considered. A series of validation experiments were conducted under various exhaust rates. The experimental data agreed well with calculated results from the model: the mean error was around 1.62 °C.