Radiant heat flux to external surfaces from escaping and extrusive flashover flames

Current practice when predicting safe separation distances between buildings is to assess the radiant hazard posed by flames and hot gas visible across the vent. The vent is treated as a radiating vertical surface with a representative temperature. A method is proposed for calculating the radiant heat flux to external surfaces from hot gas and extrusive flame emerging from a vent in a compartment wall containing post-flashover fire. An experimental study has been made to examine the validity of the method for extrusive flames unaffected by wind.