External venting flame models: Criticality and challenges of application in a large-scale informal settlement fire spread model

Informal settlements can be prone to extensive fire spread, driven to a significant degree by external venting flame (EVF). Development of a successful large-scale urban fire spread model hinges on the applied submodels’ ability to quantify EVF characteristics. The first characteristics to capture are the flame dimensions, however, existing empirical models for this are found to be inaccurate and/or contextually inappropriate for direct application to informal settlement fire spread scenarios. This paper attempts to numerically verify current flame dimension models highlighting where there are discrepancies in the numerical theory that underpin them. New empirical correlations are then created for EVF height and length that, whilst subject to further data input, more robustly capture EVF characteristics seen in experiments.