On the front velocity of buoyancy-driven transient ceiling jet in a horizontal corridor: Comparison of correlations with measurements

Front velocity of transient ceiling jet is a major concern for building fire safety. This work concentrates on the front velocity of transient ceiling jet in corridor fires. Experiments with both steady fire sources and a developing fire source are performed to evaluate the applicability of existing theoretical correlations for a relatively long corridor. To account for the conditions with significant heat loss from smoke flow, some modifications for these correlations are proposed by this work. Results show that the classical Hinkley’s correlation without consideration of the heat loss can significantly over-predict the front velocity of transient ceiling jet at the remote locations with relatively low temperatures (e.g., less than 80 °C). Jones’ model, Benjamin’s model and CFAST’s model also over-predict the front velocity at these low temperatures, but with much smaller deviations in relation to Hinkley’s correlation. The modified Hinkley’s correlation, with consideration of the heat loss from smoke flow, produces more acceptable predictions for both steady and growing fires.

► Ceiling jet front velocity is experimentally investigated in a corridor.
► Model predictions are compared with the measurements for ceiling jet front velocity.
► Hinkley’s model can over-predict the ceiling jet front velocity as high as 180%.
► The modified Hinkley’s model with considering heat loss gets good predictions.