Journal of Fire Sciences

This work investigates the parameters influencing the mechanical resistance of intumescent chars. A polyurethane matrix containing 30 wt% of ammonium polyphosphate was used in this study as intumescent model system. Three heating devices (rheometer furnace, mass loss calorimeter, and tubular oven) were used as heat treatment scenarios to obtain a charred structure. This char is then analyzed by measuring its compression resistance using a protocol involving a plate–plate rheometer (estimation of the char strength). The study of the char strength reveals that the presence of a flame, the heating type (convective or radiative heating), and the quenching temperature do not modify the mechanical properties of the resulting intumescent char. On the contrary, it was found that the critical parameters involved in the formation of a resistant char are the heating temperature and the heating rate. The strongest charred structure is reached after a heat treatment at 10°C/min until 500°C. Additionally, the modification of the temperature at which the mechanical test is performed (linked to the experimental protocol) leads also to different mechanical resistance of the tested materials.

Radiative properties such as temperature and emissive power distributions are very essential for fire safety measurements. The objective of this study is to characterize these distributions for a gasoline pool fire both experimentally and numerically. Infrared thermal camera is employed for the measurement of temperature distributions of gasoline open pool fires for pool diameters of 0.3, 0.5, 0.7 and 1.0 m. Incident heat flux upon a target is computed using the measured apparent temperature distribution and is validated with Schmidt–Boelter heat flux gauge measurements. Numerical studies are conducted using Fire Dynamics Simulator 5.5.3 version. Heat flux measured of target area is used to validate the numerical simulations with the experimental results. Centerline temperature distribution of numerical simulation and the temperature distribution from the experimental results are compared. It is observed that Fire Dynamics Simulator is capable of simulating the open pool fires even for complex fuels such as gasoline.

A two-component polyurea elastomer is evaluated for fire retardancy using the cone calorimeter and thermal analysis. The content of the fire retardant, aluminum diethylphosphinate, the thickness, and heat flux were varied. Thicker samples (12 mm) containing about 3% phosphorus (~15% aluminum diethylphosphinate) seem to be the best.

The main purpose of this study is to investigate the effects of nanoclays on the flammability behavior of neat polystyrene and polystyrene compounded with traditional flame retardants triphenyl phosphate and its synergist melamine cyanurate. Nanocomposites were prepared via ultrasound-assisted solution intercalation technique. Dispersion and nanomorphology of nanoclays were investigated through X-ray diffraction analysis and transmission electron microscopy. Thermal stability and flammability behaviors were evaluated by thermogravimetric analysis, limiting oxygen index, and mass loss calorimeter tests. These analyses indicated that addition of only 5% nanoclays resulted in significant improvements in many flame retardancy parameters of polystyrene. These improvements were more pronounced in the specimens with triphenyl phosphate and triphenyl phosphate–melamine cyanurate due to the synergistic combination of “condensed phase” action of nanoclays and “gas phase” actions of triphenyl phosphate and melamine cyanurate.

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⁻¹ 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.