Showing papers in "Journal of Fire Sciences in 2014"
TL;DR: In this article, the authors explore the mechanisms of horizontal flame spread over thermal insulation foam surfaces, extruded polystyrene and expanded poly styrene foams were selected to carry out a series of experiments with different sample widths ranging from 4 to 16 cm.
Abstract: In order to explore the mechanisms of horizontal flame spread over thermal insulation foam surfaces, extruded polystyrene and expanded polystyrene foams were selected to carry out a series of experiments with different sample widths ranging from 4 to 16 cm. Temperatures in both the solid phase and the gas phase were measured, with considerable differences being found between extruded polystyrene and expanded polystyrene in their temperature profiles. Extruded polystyrene also showed a distinct pyrolysis stage, while expanded polystyrene showed a lengthy melting stage differences that may be explained from their different thermal properties. The flame spread rates of both materials first decreased and then increased with increasing sample widths. The minimum flame spread rates were at widths of 8 and 10 cm for extruded polystyrene and expanded polystyrene, respectively, resulting from the relative differences between convection and radiation heat flux, which were different for the two foams. Numerical equa...
43 citations
TL;DR: In this article, polyethylene was flame retarded with two intumescent type additives, 3,5-diaminobenzoic acid phosphate and ethylenediamine phosphate, along with varying ratios of two grades of expandable graphite, also differing with respect to their onset temperatures for exfoliation.
Abstract: Polyethylene was flame retarded with two intumescent-type additives, 3,5-diaminobenzoic acid phosphate and ethylenediamine phosphate, which differ with respect to their decomposition onset temperatures, along with varying ratios of two grades of expandable graphite, also differing with respect to their onset temperatures for exfoliation. Hot-pressed sheet specimens were subjected to evaluation in a cone calorimeter. Although the best char yields were obtained with formulations containing the higher decomposition temperature intumescent, 3,5-diaminobenzoic acid phosphate, the overall best performance was realized using the lower decomposition temperature intumescent, ethylenediamine phosphate, when compounded together with the low exfoliation temperature expandable graphite. These results are attributed to the formation, at the burning surface, of a more cohesive char with better thermal and mass transfer barrier properties.
26 citations
TL;DR: In this paper, the fire performance of silicone-based coatings containing expandable graphite, organoclay, and calcium carbonate was evaluated in cellulosic fire scenario (standard ISO834) using a lab-scal...
Abstract: The fire performance of curable silicone-based coatings containing expandable graphite, organoclay, and calcium carbonate is evaluated in cellulosic fire scenario (standard ISO834) using a lab-scal...
24 citations
TL;DR: In this article, a global non-dimensional four-regions correlation (continuous flame region, intermittent flame regions, line-plume region, and axi-symmetric plume region) is proposed to characterize the axial temperature profile of a line-source jet fire plume.
Abstract: This article investigates flame height and axial temperature profile of a buoyant turbulent line-source jet fire plume. Previous correlations have been mainly for axi-symmetrical fire sources or linear pool-type (no initial momentum) fire sources. Experiments were carried out for this study using a 3 mm (width) x 95 mm (length) line-source nozzle with propane as the fuel. Flame heights and axial temperature profiles were measured for different heat release rates. It was found that the flame heights can be well correlated by flame Froude number with a 2/3 power function based on scaling analysis. A global non-dimensional four-regions correlation (continuous flame region, intermittent flame region, line-plume region, and axi-symmetric-plume region) is proposed to characterize the axial temperature profile of a line-source jet fire plume.
23 citations
TL;DR: Light gauge steel frame wall systems are commonly used in industrial and commercial buildings, and there is a need for simple fire design rules to predict their load capacities and fire resistance as discussed by the authors,...
Abstract: Light gauge steel frame wall systems are commonly used in industrial and commercial buildings, and there is a need for simple fire design rules to predict their load capacities and fire resistance ...
22 citations
TL;DR: In this article, the authors investigated the accelerating forest fire phenomenon for two real accidents using the thermochemical hypothesis, based on the ignition of a biogenic volatile organic compounds cloud accumulated in canyons.
Abstract: The accelerating forest fire phenomenon for two real accidents is studied. This phenomenon is investigated using the thermochemical hypothesis, based on the ignition of a biogenic volatile organic compounds cloud accumulated in canyons. By heating a Rosmarinus officinalis plant in a specific hermetic enclosure, a mixture of 14 biogenic volatile organic compounds is identified and their mass fractions determined as temperature functions. The theoretical flammability limits of those components are calculated by means of empirical correlations. Froude-scaling law is applied to laboratory emission results to find the concentrations of biogenic volatile organic compounds at field scale. The comparison of the flammability limits with the calculated concentrations at real scale using this changing-scale analysis shows that the emitted biogenic volatile organic compounds can lead to an accelerating forest fire. Language: en
21 citations
TL;DR: In this article, large-scale experiments of n-heptane and gasoline continuous spill fires were conducted in an open area to study the spread and burning behavior of continuous liquid fuel spill fires on water.
Abstract: Large-scale experiments of n-heptane and gasoline continuous spill fires were conducted in an open area to study the spread and burning behavior of continuous liquid fuel spill fires on water. The ...
20 citations
TL;DR: In this article, the main aim was to investigate contribution of nanoclays to the flame retardancy of two cable insulation materials: low-density polyethylene and its blend with ethylene vinyl acetate.
Abstract: The main aim of this study was to investigate contribution of nanoclays to the flame retardancy of two cable insulation materials: low-density polyethylene and its blend with ethylene vinyl acetate...
20 citations
TL;DR: In this paper, the performance of three kinds of transition metal ions (Mn2+, Cu2+, and Zn2+) modified zeolite 4A particles in suppressing methane/air coflowing flames on cup burner was investigated.
Abstract: This study investigated the performance of three kinds of transition metal ions (Mn2+, Cu2+, and Zn2+) modified zeolite 4A particles in suppressing methane/air coflowing flames on cup burner. Ion-e...
20 citations
TL;DR: In this article, it is known that for the production of halogen-free cable insulation materials based on polyethylene, very high amounts of traditional metal hydroxide flame retardants such as 65 wt% aluminum hydro...
Abstract: It is known that for the production of halogen-free cable insulation materials based on polyethylene, very high amounts of traditional metal hydroxide flame retardants such as 65 wt% aluminum hydro...
18 citations
TL;DR: In this article, the authors investigated the causes of the synergistic effect observed when a combination of flame retardants (FR; aluminum phosphinate/melamine polyphosphate) and organomodified montmorillonite (o-MMT) is used in polyamide 6.
Abstract: Investigations have been performed to determine the causes of the synergistic effect observed when a combination of flame retardants (FR; aluminum phosphinate/melamine polyphosphate) and organomodified montmorillonite (o-MMT) is used in polyamide 6 (PA6). Structures obtained at different stage of degradation in cone calorimeter experiments for the PA6, PA6/FR, PA6/o-MMT, PA6/FR/o-MMT are compared. The evolution of the chemical species formed according to the stages of degradation together with the characterization of the resistance of the char have enabled to elucidate the mechanism of protection involved for PA6/FR/o-MMT. Infrared characterizations have demonstrated that the species formed are degradation products of the components of the formulation that are also observed for PA6/FR and PA6/o-MMT and do not explain the improved performances. However, the structure of the char with clay distinguishes itself with a very specific small closed-cells foamed structure exhibiting an enhanced char strength. A d...
TL;DR: In this paper, a method of using pure helium to generate a cold buoyant plume as the surrogate of a fire smoke for the study of the smoke-filling process in an atrium was developed.
Abstract: This study developed a method of using pure helium to generate a cold buoyant plume as the surrogate of a fire smoke for the study of the smoke-filling process in an atrium. Aided by the numerical ...
TL;DR: In this article, the pyrolysis and piloted ignition behavior of thermally thick paulownia wood brick for different orientations has been experimentally investigated, by using the conical heater.
Abstract: In this work, the pyrolysis and piloted ignition behavior of thermally thick paulownia wood brick for different orientations has been experimentally investigated, by using the conical heater. Three...
TL;DR: In this article, the relationship between internal fire whirls generated in a vertical shaft model was studied and four fuels including methanol, ethanol, propanol, and methanoline were used.
Abstract: Relationship between internal fire whirls generated in a vertical shaft model was studied. A vertical shaft model of height 145 cm was constructed. Four fuels including methanol, ethanol, propanol,...
TL;DR: In this paper, a polypropylene-grafted starch, containing ammonium polyphosphate as flame retardant, was used as a fire retardant for intumescent Gaialene.
Abstract: Mechanisms of fire retardancy of intumescent Gaialene® (a polypropylene-grafted starch, containing ammonium polyphosphate as flame retardant) exhibiting high performance (60% reduction of the peak ...
TL;DR: In this article, the flammability and thermal stability of ammonium polyphosphate-treated flame-retarded sawdust boards were compared with those also containing 5A zeolite and 5A zerosolite that had been impregnated with 4-picolinic acid.
Abstract: The flammability and thermal stability of ammonium polyphosphate–treated flame-retarded sawdust boards were compared with those also containing 5A zeolite and 5A zeolite that had been impregnated with 4-picolinic acid. This comprehensive study was performed using cone calorimetry, thermogravimetric analysis and scanning electron microscopy. The results demonstrated that acid-treated 5A zeolite, which was incorporated into ammonium polyphosphate–based flame-retardant systems, showed superior performance to ammonium polyphosphate being used alone. This was determined by comparing the peak heat release rate, total heat release, fire growth index, smoke release rate, and total smoke emission. The thermogravimetric analysis results showed that 4-picolinic acid significantly altered the thermal stability of ammonium polyphosphate, which was catalytically decomposed in advance so as to retard combustion. Digital photography and scanning electron microscopy observations showed that 5A zeolite used with 4-picolini...
TL;DR: In this paper, the effect of surface modification of a layered silicate (magadiite) on the flammability of both polyurea and amine-cured epoxy resin was investigated.
Abstract: The purpose of this study is to investigate the effect of the surface modification of a layered silicate (magadiite) on the flammability of both polyurea and amine-cured epoxy resin. Based on the surface chemistry of magadiite, both quaternary alkyl ammonium and silane modifier can be employed for the organo-modification. Nanocomposites of both polymers were prepared via ultrasound-assisted in situ polymerization. Dispersion of magadiite was investigated through X-ray diffraction and high-resolution transmission electron microscopy. Thermal stability and flammability were evaluated by thermogravimetric analysis and cone calorimetry, respectively. The addition of small amount of magadiite resulted in significant improvements in flame resistance with not much change in thermal stability for both polymers. Ammonium-modified magadiite improves the flame resistance, whereas silane modification helps to increase time to ignition of both polymers.
TL;DR: In this article, the main fire retardancy mechanism of polymer-clay nanocomposites involves the progressive build-up of an inorganic-rich layer at the sample surface during combustion, by a combination of ablative reassembling and migration of the nanoparticles, reducing heat and mass transfer between gas and condensed phases.
Abstract: The main fire retardancy mechanism of polymer–clay nanocomposites involves the progressive build-up of an inorganic-rich layer at the sample surface during combustion, by a combination of ablative reassembling and migration of the nanoparticles, reducing heat and mass transfer between gas and condensed phases In this process, a non-negligible amount of polymer needs to be sacrificed before the entire surface of the residual material is shielded This study aims to improve the fire behaviour of polymer–clay nanocomposites by accelerating the physical barrier formation through the development of new hybrid structures For that purpose, a system based on polyamide 12 and halloysite nanotubes is chosen as reference and highly loaded nanocomposite films are coated on a virgin PA12 substrate Both the influence of clay fraction in the nanocomposite film and its thickness on the flammability performance of the coated samples are evaluated by mass loss calorimetry and compared to that of homogeneous ‘bulk’ nanocomposites Results show unambiguously that hybrid materials are more effective than conventional nanocomposites to flame retard polymers while substantially reducing the total filler loading, and so the cost of the final product Moreover, a small amount of carbon nanotubes can be incorporated in the polymer substrate and/or in the nanocomposite film to suppress the vigorous bubbling of evolved degradation products as well as to reduce the flexibility of the thin protective skin, which can cause detrimental effects on its barrier properties
TL;DR: In this paper, material selection and construction design were considered for an appla-mentionment of a portable shelter using a composite core panel for lightweight construction and portable shelter use.
Abstract: Polymer composite sandwich core panels are of interest for lightweight construction and portable shelter use. In this article, material selection and construction design were considered for an appl...
TL;DR: The Journal of Fire Sciences (JFS) Forum as discussed by the authors provides a forum for dialogue and discussion within the fire science community, but contributions to The Forum will not be refereed in the conventional sense, but will be subject to review by the Editor or a member of the Journal’s Editorial Board relative to appropriateness, clarity, timeliness, and scope of interest.
Abstract: Journal of Fire Sciences 2014, Vol. 32(3) 281–291 The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0734904114528457 jfs.sagepub.com The Forum is intended to provide for dialogue and discussion within the fire science community. Contributions to The Forum will not be refereed in the conventional sense, but will be subject to review by the Editor or a member of the Journal’s Editorial Board relative to appropriateness, clarity, timeliness, and scope of interest. The Editor will be the sole judge of those contributions to be published. Opinions expressed, however, are those of the authors and not of the Editor or Sage Publications, Ltd.
TL;DR: In this paper, a functional simulation method was applied to study the pre-ignition temperature variations of wire insulation under overload conditions in normal gravity, but under reduced pressures, compared with microgravity experimental results in order to investigate the effects of pressure and current on the wire insulation.
Abstract: A functional simulation method was applied to study the pre-ignition temperature variations of wire insulation under overload conditions in normal gravity. A simplified heating mode was proposed to theoretically investigate the wire heating process. Results of the temperature variations of wire insulation prior to ignition in normal gravity, but under reduced pressures, were obtained and compared with microgravity experimental results in order to investigate the effects of pressure and current on the pre-ignition thermal features of the wire insulation. Results show that the functional simulation method was effective to simulate the natural convection heat transfer effect on the wire insulation, which is a useful alternative approach to predict the pre-ignition thermal features of wire insulation by overload over a long duration in a microgravity environment.
TL;DR: In this article, the effects of altitude and intersection angle on the flame spread behavior and pyrolysis front characteristics along corner walls were experimentally studied, and the experiments were conducted using a fire extinguisher.
Abstract: The effects of altitude and intersection angle on the flame spread behavior and pyrolysis front characteristics along corner walls were experimentally studied. The experiments were conducted using ...
TL;DR: In this paper, the smoldering propensity of commercially available barrier fabrics in a small-scale mock-up configuration was reported. But, when covered with a smolder-prone cover fabric, most barrier fabrics failed the standard 16 CFR Part 1634.
Abstract: This study reports on the smoldering propensity of commercially available barrier fabrics in a small-scale mock-up configuration. Most barrier fabrics are smolder resistant when tested alone over a standard flexible polyurethane foam. However, when covered with a smolderprone cover fabric, most barrier fabrics failed the smoldering ignition test described in the Consumer Product Safety Commission’s proposed standard 16 CFR Part 1634. The results of this study suggest that the smolder-prone cover fabrics, when placed on top of a number of barrier fabrics, are capable of releasing sufficien th eat to initiate the char oxidation smoldering process of some of the barrier fabrics and subsequently transmit the heat to the underlying flexible polyurethane foam. A smoldering index for barrier fabrics was derived from the measured char volume fraction of the flexible polyurethane foam by varying the barrier fabric component in the flexible polyurethane foam/barrier fabric/cover fabric mock-up systems, while holding the other two components constant. The smoldering index for self-extinguishing barrier fabrics was 0. Barrier fabrics with smoldering index of 1 or more resulted in sustained smoldering in the flexible polyurethane foam. The smoldering propensity of barrier fabrics and the amount of heat transmitted to the flexible polyurethane foam varied depending on the barrier fabric structure, fiber content, air permeability, and bulk density. Flame-retardant treatments and use of char-forming fibers showed a greater tendency for barrier fabric smolder in the presence of the smolder-prone cover fabric. Barrier fabrics with char-forming fiber blends had greater smoldering propensity as compared to barrier fabrics with low charring fiber
TL;DR: In this paper, the authors used a flash pyrolysis device linked to a gas chromatograph/mass spectrometer to investigate experimentally the biogenic volatile organic compounds emissions of Thymus vulgaris, Lavandula stœchas, and Cistus albidus between 70°C and 180°C.
Abstract: Vegetal species emit biogenic volatile organic compounds at elevated temperatures. Because of their combustibility, biogenic volatile organic compounds can modify the wildland fires propagation dynamics, changing them from a moderate behavior to an explosive propagation. This phenomenon is known as an accelerating forest fire. The origin of such phenomena can be the accumulation of biogenic volatile organic compounds in concentrations close to their lower flammability limit in seasons where the plants are themselves very flammable. There is a lack of information on the biogenic volatile organic compounds emissions of vegetal species typically found in wildland fires at temperatures higher than ambient temperature. In this work, we used a flash pyrolysis device linked to a gas chromatograph/mass spectrometer to investigate experimentally the biogenic volatile organic compounds emissions of Thymus vulgaris, Lavandula stœchas, and Cistus albidus between 70°C and 180°C. High amounts of terpenoid compounds were found, except for C. albidus emissions, including thymol, l-fenchone, and 3-hexen-1-ol. The information provided in this work could help to improve the characterization of thermal degradation of vegetal fuels and to incorporate the biogenic volatile organic compounds combustion in physical forest fires models. They also show that under the right circumstances, biogenic volatile organic compounds from these vegetal species could contribute to the development of an accelerating forest fire. Language: en
TL;DR: In this paper, the effect of fuel depth on flame spread over aviation kerosene and the characteristics of the subsurface flow has been investigated using schlieren system and a high-speed camera.
Abstract: The effect of fuel depth on flame spread over aviation kerosene and the characteristics of the subsurface flow has been investigated using schlieren system and a high-speed camera. For flame spread over aviation kerosene, there are shallow pool and deep pool regimes separated by a fuel depth of 8 mm. For the shallow pool regime, the pulsation amplitude of the main flame and the precursor flame increases, but the pulsation frequency of the flames decreases with an increase in fuel depth. For the deep pool regime, fuel depth has no obvious effect on the flame pulsation and the ratio of the length to the depth of the subsurface flow. The theoretical model of the rate of the subsurface flow based on the surface tension effect agrees well with experimental values.
TL;DR: In this paper, the thermal stability and fire performance of polyurea with silylated α-zirconium phosphate and ammonium polyphosphate was studied, and it was shown that the addition of ammonium pyrophosphate reduces the thermal stabilisation.
Abstract: The thermal stability and fire performance of polyurea with silylated α-zirconium phosphate and ammonium polyphosphate are studied. The addition of ammonium polyphosphate reduces the thermal stabil...
TL;DR: In order to improve the fire resistance of a fluoroelastomer when used as an insulating material, a combination of a triazine-based polymeric charring-foaming agent and ammonium polyphosphate as a...
Abstract: In order to improve the fire resistance of a fluoroelastomer when used as an insulating material, a combination of a triazine-based polymeric charring-foaming agent and ammonium polyphosphate as a ...
TL;DR: An iron-based flame-retardant reinforcing agent was prepared by hydrothermal method using ferric sulfate Fe2(SO4)3 and urea as starting materials as mentioned in this paper.
Abstract: An iron-based flame-retardant reinforcing agent was prepared by hydrothermal method using ferric sulfate Fe2(SO4)3 and urea as starting materials. The product was characterized with respect to crystal structure and thermolysis behavior, respectively, by means of X-ray diffraction and thermogravimetric differential thermal analysis. Upon combining these with Fourier transform infrared spectroscopy, it was identified as ferric hydroxide oxide with a chemical composition of FeOOH·0.43H2O. The product was compounded with aluminum trihydroxide to flame-retard poly(ethylene-co-1-octene); the effect of FeOOH content on flame retardancy of the poly(ethylene-co-1-octene) was investigated, based on which the synergistic flame-retardant mechanism was discussed. The results show that addition of a small quantity of FeOOH can remarkably improve the flame retardance of poly(ethylene-co-1-octene)/aluminum trihydroxide compound. When the additive amount of FeOOH is 1.5 phr, the limiting oxygen index of the compound is 30...
TL;DR: Based on the nonlinear dynamics of building structures, the authors proposed a flashover model for building structures of long-narrow spaces, which is different from the study of flashover models from the conventional theory.
Abstract: The particularity in building structures of long–narrow spaces makes it different from the study of flashover model from the conventional theory. In this article, based on the nonlinear dynamics th...