This paper presents an experimental and numerical investigation of the effects of intumescent coating and nanoparticles on the burning behaviors of flaxboard. Virgin flaxboard samples and those coated with intumescent coatings (with/without nanoparticles) were tested in the cone calorimeter and single burning item (SBI) test. Experimental results show a significant increase in the time to ignition and also a reduction in the heat release rate by the intumescent coatings. In order to explain quantitatively and predict the effects of the intumescent coating, a global fractional factor (the ratio of the heat flux at the interface of the intumescent surface and the char layer of flaxboard to the surface heat flux when there is no intumescent coating layer) was introduced based on analytical solutions for charring materials. The fractional factor for the intumescent coatings was found by comparing predictions to the experimental data in the cone calorimeter test and, subsequently, was incorporated in an upward flame spread model, along with the ignition and thermal properties deduced from the ignition tests, to predict the burning rates in the SBI tests. Copyright © 2011 John Wiley & Sons, Ltd.

SummaryThis paper investigates the effects of brominated and halogen-free fire retardants on the fire performance of glass-fiber (GF) reinforced poly(butylene terephthalate) (PBT). Brominated polystyrene was used as the brominated fire retardant, whereas aluminum diethylphosphinate with/ without nanoclay as halogen-free fire retardants (HFFRs). Tests were conducted by using thermogravimetric analysis, limiting oxygen index (LOI), UL94, and the cone calorimeter. Thermogravimetric analysis results show that decomposition of GF plus PBT (PBT + GF) starts earlier in the presence of all fire retardants (FRs). In the cone calorimeter, all FRs reduce significantly the heat release rate (HRR) compared with PBT + GF, with brominated polystyrene achieving lowest HRR primarily because bromine released in the pyrolysis gases inhibits combustion. Brominate polystyrene does not, however, affect the mass loss rate. Aluminum diethylphosphinate alone has significant effects on reduction of both HRR and mass loss rate, which become considerably more when combined with nanoclay. It was also found that the combustion efficiency of the brominated polystyrene compound is much lower than that of HFFRs, indicating that brominated polystyrene has higher gas phase flame retardant efficiency compared with HFFRs because the bromine radicals released during degradation of brominated polystyrene effectively quench the chemical reactions of the pyrolysis gases due to degradation of PBT. KEYWORDS brominated fire retardants, cone calorimeter, halogen-free fire retardants, LOI, thermogravimetric analysis, UL94

Modern day energy codes are driving the design and multi-layered configuration of exterior wall systems with a significant emphasis on achieving high performance insulation towards improving energy performance of building envelopes. Use of highly insulating polyisocyanurate (PIR) based materials enhanced with eco-friendly lamellar inorganic fillers reinforces energy performance requirements, environmental challenges and cost reduction without compromising the overall building fire safety. The current work assessed the fire behaviour of PIR modified with three layered fillers, namely MgAlCO3 (PIR-LDH1), MgAl Stearate (PIR-LDH2) and Zirconium Phosphate octadecylamine (PIR-ZrP3). For each of the fillers, three loadings (2, 4 and 6 % by weight) were used.Optical analysis by X-ray diffraction patterns (XRD), cone calorimeter (CC), thermogravimetric (TGA) analysis, post-burning morphological evaluation using field emission scanning electron microscope (FESEM) and diffuse reflectance infrared spectroscopy (DRIFT) analysis, were performed. The results indicated that fire reaction properties and thermal stability of foam samples were enhanced with three different types of lamellar inorganic smart fillers. The initial degradation temperature of PIR-layered filler samples was increased, demonstrating that incorporation of flame retardants decelerated the degradation of PIR foam and contributed to significant char formation, from 19.5% in pure PIR samples to 33% in PIR-6%LDH1 samples. Increasing the filler content also resulted in improved char properties and decreased peak Heat Release Rates (HRR) in the cone calorimeter.Due to the development of a stable char layer, samples containing 6% of ZrP3 did not ignite at 20kW/m 2 and a reduction of up to 40% in the peak HRR was achieved in PIR-2%ZrP3 samples.

This article presents an experimental investigation of ignition and burning behaviors of intumescent coatings and nanoparticles applied on flaxboard using the cone calorimeter, single burning item (SBI) and reduced scale (one-third) ISO room. The effects of intumescent coatings and nanoparticles on time to ignition (TTI), mass loss rate (MLR), heat release rate (HRR), production of toxic gases (carbon monoxide and smoke) were investigated. The performance of intumescent coatings in under-ventilated condition was examined by performing tests in the one-third ISO room with reduced opening sizes. Results in the cone calorimeter and SBI indicated that (1) there is a substantial increase of TTI and decrease of MLR/HRR by intumescent coatings and (2) the addition of nanoparticles results in a further increase of TTI as well as a decrease of MLR/HRR owing to increased stability of the char. Tests in the one-third ISO room showed that although the intumescent coatings reduce the HRR the reduction is much less substantial than that in the cone calorimeter or SBI.

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