Fire Impact on Vertical Components Subjected to a Localised Fire Estimated Using a Line Source Model

Most of localised fire models focused on the heating impact on horizontal members at the ceiling level or the temperature inside the fire plume. Limited models describe the heat received by vertical surfaces due to a localised fire. As localised burning is prevailing in modern large compartments with sufficient ventilation, suitable fire models to quantify the heat fluxes on vertical components are under essential need. Advancing from the point source model that assumed radiation emitting from a virtual concentrated point, this paper proposes a line source model accounting for the radiant energy discharged along a vertical line to the target surface to improve the heating impact estimation. Non-uniform radiative power in slices and flame radius distributions along the flame height are derived with normalisation and necessary assumption. Multiple datasets obtained from experimental tests and numerical simulation are used to validate the proposed model, demonstrating good performance with mostly 10% or lower deviation. In built environment, the convective heat nearby the localised fire or in the smoke layer are found to be the main source of errors in prediction. Further modification is necessary to carefully consider the convective components if estimating the fire impact of a localised fire in large compartments.