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The integral model predictions and experimental data compare well at incident heat fluxes above around 20 kW/m 2 . At lower heat fluxes it was found that the ignition mechanism of wood is different from that at higher incident fluxes. This difference is believed to be due to char oxidation that precedes flaming ignition.The lowest radiant heat flux to cause ignition was found to be approximately 10 kW/m 2 depending on species, grain orientation or moisture content. Ignition at low heat fluxes could take up to 1½ hours.2 NOMENCLATURE α thermal diffusivity, [m 2 /s], absorptivity [-]

A non-fire-retardant and a fire retardant polyurethane foam are tested under a nitrogen environment using thermogravimetry at different heating rates of 1, 5, 20 and 60°C min 21 to obtain the foams' decomposition behaviours. During decomposition, both foams experience two major mass loss reactions with the second reaction consuming most of the fuel. Three graphical techniques applied to calculate the kinetic properties governing each reaction are kinetic analysis, the Arrhenius plot method and the inflection point methods. In general, these methods are compatible with the pyrolysis model within Fire Dynamics Simulator Version 5 and Gpyro. A normalised version of the inflection point methods is also developed to improve the suitability of the kinetic properties with the simplest decomposition scheme of the pyrolysis model. A consistent trend is noted in the calculated kinetic properties of both foams regardless of the calculation techniques applied.

Whether the balcony spill plume will rise unhindered as a free plume or curl inwards and interact with the atrium structure is determinant upon a number of factors. Not all the factors are well investigated and wholly understood, resulting in limited guidance for fire engineers. This paper systematically investigates the effects of varying balcony breadths, plume widths and fire sizes on smoke contamination in upper balconies through a series of smoke flow experiments conducted using a onetenth physical scale model representing a six-storey atrium building. The scale model simulated a fire in an adjacent compartment connecting to a fully open atrium. Visual observations and temperature measurements of the smoke flows were carried out. From the results, it was established that the extent of smoke contamination in upper balconies increased with decreasing balcony breadths, increasing plume widths and decreasing fire sizes. Analysis showed that the aspect ratio of plume width to balcony breadth can be used to determine whether smoke contamination of upper balconies will occur. Where contamination is likely, an empirical correlation was developed to determine the minimum height of contamination above the lowest balcony of smoke contamination.

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