Fire Safety Science最新文献

{"title":"Experimental and Numerical Study of Thermal Stability and Fire Performance of Brominated and Halogen-free Flame Retardants in Glass-fibre Reinforced Poly(butylene terephthalate)","authors":"M. Suzanne, A. Ramani, S. Ukleja, Maurice Mckee, Jianping Zhang, M. Delichatsios, D. Bakirtzis","doi":"10.3801/IAFSS.FSS.11-832","DOIUrl":"https://doi.org/10.3801/IAFSS.FSS.11-832","url":null,"abstract":"This paper investigates the effects of brominated and halogen-free fire retardants on the thermal stability and fire performance of glass-fibre reinforced poly(butylene terephthalate). Brominated polystyrene was used as the brominated fire retardant (BFR), whereas aluminium diethylphosphinate (Alpi) with/without nanoclay as halogen-free fire retardants (HFFRs). Tests were conducted using thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL94 and the cone calorimeter. TGA results show that decomposition of glass-fibre plus PBT (PBT+GF) starts earlier in the presence of fire retardants (FRs). In the cone calorimeter, all FRs reduce significantly the heat release rate (HRR) compared to PBT+GF, with brominated polystyrene achieving lower HRR primarily because bromine released in the pyrolysis gases inhibits combustion, without however changing the mass loss rate (MLR). Alpi alone has significant effects on reduction of both HRR and MLR, which become considerably more when combined with nanoclay. The efficiency of combustion of the brominated polystyrene compound is much lower than that of HFFRs, which indicates that unburned pyrolysing gases are released during the combustion of brominated fire retardants.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"3 1","pages":"832-845"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89281791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Convection Ignition of Live Forest Fuels","authors":"S. McAllister, M. Finney","doi":"10.3801/iafss.fss.11-1312","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1312","url":null,"abstract":"Wildland fires are an extremely costly and deadly problem. Crown fires, where live foliage ignites and burns, are particularly unpredictable – in part because live fuel ignition and combustion is poorly understood. Many wildland fire models assume radiation is the controlling heat transfer mechanism. However, there is a growing indication that radiation is insufficient to ignite the small, thin fuel particles that carry a wildland fire and that convective heating and flame bathing is a critical component. Unfortunately, ignition by convection heating of any fuel is poorly understood. Ignition of live forest fuels by any means is also completely unknown due to complicated moisture content and fuel chemistry considerations. To gain some insight into the wildland fire problem, an apparatus was built using two 6.5 kW electrical heaters to heat gas (air, nitrogen, etc.) over a range of temperatures from ambient up to 1200°C. The flow rate of these “airtorches” is adjustable. This apparatus was used to convectively ignite a range of both live and dead forest fuels. Fuels from all over the United States where used including Southern California, Utah, Florida, and Montana. To examine ignition threshold conditions and to have distinguishable differences in ignition times, air temperatures of 500°C and 600°C were used. The airflow rate varied slightly from 1.3 m/s to 1.4 m/s due to the density difference. Because live forest fuels contain large amounts of water, the evolution of both water and carbon dioxide was measured with time using a differential gas analyzer. Flaming ignition was seen for all dead fuels at 500°C, but the live fuels mostly showed glowing ignition. At 600°C, all fuels showed flaming ignition within 1-26 sec. Interestingly, all live fuels were still actively releasing water at ignition, implying there are steep temperature gradients within these physically thin fuels (i.e. not thermally thin). Simple heat transfer analysis in conjunction with the water evolution information was used to help explain the differences in ignition times due to fuel geometry.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"68 1","pages":"1312-1325"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86117333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Free-Surface Model of a Jet Impinging On a Sprinkler Head","authors":"T. Myers, A. Marshall, H. Baum","doi":"10.3801/iafss.fss.11-1184","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1184","url":null,"abstract":"Understanding the atomization of fire sprinkler sprays fills a critical gap in the modeling of fire suppression systems. Previous research by the authors has shown an instability model coupled with a stochastic transport model can paint most of the sprinkler spray picture, but requires input in the form of thickness and velocity of unstable fluid sheets. The model outlined describes a water jet impinging on a perforated deflector plate as a velocity potential. The free surface separating the jet from the surrounding air takes the form of a vortex sheet with the air assumed to be at rest. Through the use of the Green's function, the fluid velocity potential can be posed as a boundary value problem. Any solution obtained is an exact solution to the inviscid flow equations and the interior flow a solution to the Navier-Stokes equations. The resulting model allows for the determination of the complete flow field over a sprinkler head of arbitrary geometry and input conditions. Knowledge of this flow field provides insight into the impact of sprinkler head geometry and fluid velocity as well as providing the above mentioned inputs for a complete model of fire sprinkler sprays.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"13 1","pages":"1184-1195"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83356818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and survey studies on the effectiveness of dynamic signage systems","authors":"E. Galea, H. Xie, P. Lawrence","doi":"10.3801/IAFSS.FSS.11-1129","DOIUrl":"https://doi.org/10.3801/IAFSS.FSS.11-1129","url":null,"abstract":"Signage systems are widely used in the built environment to aid occupant wayfinding during both circulation and evacuation. Recent research conducted by the authors shows that only 38% of people ‘see’ conventional static emergency signage in presumed emergency situations in an unfamiliar built environment, even if the sign is located directly in front of them and their vision is unobstructed. However, most people who see the sign follow the sign. These results suggest that current emergency guidance signs are less effective as an aid to wayfinding than they potentially can be and that signs are likely to become more effective if their detectability can be improved while upholding the comprehensibility of the guidance information they provide. A novel dynamic signage design is proposed to address this issue. The effectiveness of the new sign is tested under almost identical experimental settings and conditions as in the previous experiments examining conventional, static signs. The results show that 77% of people ‘see’ the dynamic sign and 100% of them go on to follow the sign. In addition, a dynamic method to identify that an exit route is no longer viable is tested using an international survey to gauge understanding of the new signage concept. Survey results suggest that the purpose of the new sign can be clearly understood by over 90% of the sample.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"73 1","pages":"1129-1143"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89436226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Experimental Investigation of Structural Fire Behaviour of a Rigid Steel Frame","authors":"T. Hirashima, Kazuma Okuwaki, Xuansu Zhao, Y. Sagami, K. Toyoda","doi":"10.3801/iafss.fss.11-677","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-677","url":null,"abstract":"Some experimental studies have been conducted on structural fire behaviour of steel sub-frames in order to investigate the effects of thermal stress due to the axial restraint from columns to a heated beam on the behaviour of connections, and its influences on the connected beam and robustness of steel frames. However, the object connections were not beam-to-beam connections but beam-to-column connections with fin plates, end plates, and web cleats. This paper discusses, on the basis of experimental results, structural fire behaviour of a rigid steel frame with fully-moment-resisting beam-to-beam connections with splice plates and HSFG bolts, and beam-to-column connections with full penetration welds. The structural behaviour in the test was also analysed with finite element analysis using Bernoulli-Euler beam elements. The test results indicated that the moment-resisting connections in the rigid steel frame have sufficient load-carrying capacity, but failure may occur in the connected beam due to inadequate shear resistance of the beam web in fire. The critical temperature of the steel beam could be approximated on the basis of its inherent resistance at elevated temperature and initial effects, because the thermal stress disappeared at the fire limit stage. This study was also intended to provide experimental data to help understand the fundamental behaviour of rigid steel frames in fire.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"1 1","pages":"677-690"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88877982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gpyro3D: A Three Dimensional Generalized Pyrolysis Model","authors":"C. Lautenberger","doi":"10.3801/iafss.fss.11-193","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-193","url":null,"abstract":"All objects that burn in fires are three dimensional. However, almost all previous attempts to model the burning or pyrolysis of real materials has resorted to a one-dimensional description. This paper presents the mathematical formulation of Gpyro3D, a generalized three dimensional pyrolysis model that solves conservation equations for transport of heat, mass, and species in a chemically reacting porous medium, as well as its coupling to NIST’s Fire Dynamics Simulator (FDS) for simulating fire development. Gpyro3D facilitates pyrolysis modeling in complex geometries by masking grid cells on a regular Cartesian grid, similar to the way that geometry is specified in FDS. The model’s mathematical formulation is verified by comparing numerical simulations to analogous exact solutions. Next, it is shown that Gpyro3D qualitatively captures the major three dimensional features of long-duration (> 1 hour) oxidative pyrolysis of wet wood under radiative heating. Finally, fire development in a wood crib is simulated with the coupled Gpyro3D/FDS model. By observing condensed-phase temperature contours within burning elements of the wood crib, it is shown that strong three dimensional effects are present.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"4 1","pages":"193-207"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80920622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new Experimental Rig for Oil Burning on Water – Results for Crude and Pure Oils","authors":"Nicholas L. Brogaard, Martin X. Sørensen, J. Fritt-Rasmussen, A. Rangwala, G. Jomaas","doi":"10.3801/iafss.fss.11-1481","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-1481","url":null,"abstract":"A new experimental apparatus, the Crude Oil Flammability Apparatus (COFA), has been developed to study in-situ burning of crude and pure oils spilled on water in a controlled laboratory environment with large water-to-oil ratios. The parameters and phenomena studied for an asphaltic crude oil (Grane) and two pure oils (n-Octane and dodecane) with different initial oil layer thicknesses include burning efficiency, burning rate, regression rate, flame height and boilover. Pyrex glass cylinders (157 and 260 mm ID) placed on top of a steel foot in a water basin (1m x 1m x 0.5m) enabled free circulation of the water, which, along with the large water-to-oil ratios (up to 10,000) ensured that the oil burning barely increased the temperature of the surrounding water environment, which created more realistic offshore conditions than seen in many other laboratory studies. The burning efficiency was found to be nearly 100% for n-Octane and of dodecane, whereas the crude oil burning efficiency ranged between 35% and 65%. The main reason for this variation proved to be the onset of an extremely violent boilover, which occurs for oils with relatively high boiling temperatures when the water sub layer is superheated. When the initial crude oil layer thickness exceeded 20 mm the oil became solid and no boilover occurred. The heat-loss to the water sub-layer also had an effect on the burning efficiency and the regression rate was found to reach a constant value after increasing continuously as the oil was heated. Similar results were found regarding the flame height which reached a steady flame height. The pure fuels, n-Octane and dodecane, produced a much higher steady flame height than the crude oil, however they did not reach boilover, though dodecane showed boilover tendencies. Theoretical predictions with existing correlations and input data specific for the current oils generally compared well with the experimental data for both the time to boilover and the regression rates. As such, the COFA is envisioned to produce high-fidelity results in the future and thereby contribute to the further development of in-situ burning as an alternative response technique for oil spills on water.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"1 1","pages":"1481-1495"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87946735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intumescent silicone-based coatings for the fire protection of carbon fiber reinforced composites","authors":"S. Bourbigot, B. Gardelle, S. Duquesne","doi":"10.3801/iafss.fss.11-781","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-781","url":null,"abstract":"The application of carbon fiber reinforced polymer (CFRP) in aircraft structure has introduced potential fire threats and fire protection must be provided. In this paper, intumescent silicone based-coatings (low and high intumescing coatings) are evaluated on CFRP using a bench developed in the laboratory mimicking a jet fuel fire occurring at high heat flux (200 kW/m2). It is shown the development of large intumescence (high intumescing coating) associated with appropriate thermal properties of the coating (heat conductivity measured as low as 0.3 W/m.K) provides efficient protection for the CFRP at the jet fire test. On the other hand, the formation of cohesive ceramic (low intumescing coating) with low heat conductivity (constant heat conductivity as a function of temperature of 0.35 W/m.K) also provides protection but its efficiency is lower than that of intumescent char. It is evidenced that intumescent silicone-based coatings are materials of choice for protecting CFRP in the case of jet fuel fire.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"49 1","pages":"781-793"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77952434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Iron Hydroxyl Phosphate Particles on the Thermal Stability and Combustible Properties of Polymethyl methacrylate","authors":"Lei Wang, Chenlu Bao, Yang Wei, H. Yuan, Lei Song, K. RICHARDK., Yuen","doi":"10.3801/iafss.fss.11-860","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-860","url":null,"abstract":"The iron hydroxyl phosphate Fe3.6Fe1.02(OH)2.17(PO4)3O0.84(FePOH) nanoparticles were synthesized by hydrothermal method at a relative low temperature. The iron hydroxyl phosphate nanoparticles were then incorporated into poly (methyl methacrylate) (PMMA) by in situ radical polymerization. Thermogravimetric analysis (TGA) data showed that the presence of FePOH remarkably improved thermal stability and promoted the formation of char residues of PMMA matrix. For the PMMA in combination with 6 % FePOH, the heat release capacity which is an indicator of a material fire hazard was reduced by 48 %. The residue characterization and thermogravimetric analysis/fourier transform infrared spectrometry (TGA-FTIR) revealed the carbonization behavior of iron hydroxyl phosphate in PMMA matrix and probably the appearance of Fe(CO)5 during the thermal decomposition of PMMA/2 %FePOH composite, which may is the reason for the improvement in the thermal and combustion properties.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"64 1","pages":"860-873"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84778983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on temperature property along a tunnel axis with flat ceiling in natural ventilation","authors":"Y. Oka, H. Oka, Osamu Imazeki","doi":"10.3801/iafss.fss.11-472","DOIUrl":"https://doi.org/10.3801/iafss.fss.11-472","url":null,"abstract":"In this study, detailed measurements of the temperature in a horizontal tunnel with a rectangular cross section were conducted. The temperature decrease along the tunnel axis, the thermal thickness, and the temperature distribution of a steady fire-driven ceiling jet were compared with those for an unconfined smooth-ceiling jet flow. Results of this study showed that the temperature decrease along the tunnel axis was gradual, with the thermal thickness in the tunnel being about two times than that of a ceiling jet under an unconfined ceiling. The temperature distribution in the tunnel exhibits a more bulging shape. Empirical formulae defining the temperature decrease along the tunnel axis, the thermal thickness, and the temperature distribution are also presented.","PeriodicalId":12145,"journal":{"name":"Fire Safety Science","volume":"25 1","pages":"472-485"},"PeriodicalIF":0.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82932566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}