Wind effects on smoke motion and temperature of ventilation-controlled fire in a two-vent compartment

High-rise building fire is often influenced by the ambient wind. Study concerning fire behavior in the compartment of high-rise buildings in wind environment is needed for exploring some effective methods used for evaluation of compartment fire smoke movement and control. In this paper, smoke flowing direction and temperature of ventilation-controlled fire in a two-vent compartment are studied when ambient wind blows to the vent at higher altitude. It is found that there is a critical wind speed, above which the direction of smoke movement is dominated by wind rather than by buoyancy. It is also found that ambient wind has a complex influence on smoke temperature in the compartment. When wind speed exceeds another critical value, only one steady state appears in the smoke temperature rising curve. Otherwise three steady states appear. Heat transfer through the compartment walls has great influence on the second critical wind speed.     

BRE large compartment fire tests—Characterising post-flashover fires for model validation

Reliable and comprehensive measurement data from large-scale fire tests are needed for validation of computer fire models, but is subject to various uncertainties, including radiation errors in temperature measurement. Here, a simple method for post-processing thermocouple data is demonstrated, within the scope of a series of large-scale fire tests, in order to establish a well characterised dataset of physical parameter values which can be used with confidence in model validation. Sensitivity analyses reveal the relationship of the correction uncertainty to the assumed optical properties and the thermocouple distribution. The analysis also facilitates the generation of maps of an equivalent radiative flux within the fire compartment, a quantity which usefully characterises the thermal exposures of structural components. Large spatial and temporal variations are found, with regions of most severe exposures not being collocated with the peak gas temperatures; this picture is at variance with the assumption of uniform heating conditions often adopted for post-flashover fires.