共查询到20条相似文献，搜索用时 0 毫秒
1.
A cone calorimeter was used to test inorganic water‐releasing and low‐melting compounds as flame retardants in polyurethane adhesive samples. Sodium metasilicate pentahydrate, potassium carbonate mixed with silica gel, sodium hydrogen carbonate, calcium oxalate monohydrate, zinc and magnesium chloride mixed with potassium chloride, aluminium and magnesium hydroxides, ammonium polyphosphate (APP), sodium and potassium phosphates were tested. These additives were used to partially (10–20%) replace the limestone used as a filler in the adhesive. Thermogravimetric analysis was used to study decomposition and melting of the inorganic compounds. The results showed that sodium metasilicate monohydrate formed a protective layer of sodium silicate on the sample surface, significantly delaying the time to ignition. Addition of APP resulted in the lowest overall heat release rate curve. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
2.
The aim of this study was the optimization of cone calorimeter to determine the burning behavior of textile fabrics. In particular, the combustion behavior of commercial polyester textile fabrics with varying densities was studied in terms of time to ignition (TTI), heat release rate (HRR), and relative peak (pkHRR) were monitored. Reproducibility and repeatability of the data have been verified by the influence of instrument variable including incident heat flux, the temperature of ceramic backing pads and retaining grid used during sample mounting as well as sample weight (as the number of fabric layers), the density of textiles, and the relative humidity. A low reproducibility has been obtained when a wire grid was not used to stabilize samples during the tests. The effects of these variables on TTI and pkHRR were observed. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
3.
The effects of retainer frame use, irradiance level and specimen thickness were studied as the second phase work of a round robin project on the cone calorimeter. The project was conducted in support of various U.S. building code groups, developing a system to determine the degrees of combustibility of building materials. The results of the second phase and a comparison with the corresponding round robin results conducted at 75 kW/m2 according to the Board for the Coordination of the Model Codes (BCMC) protocol, are presented here. For most of the materials, no significant differences in parameters measured in the cone calorimeter were found when the retainer frame was not used, versus when the retainer frame was used. The irradiance of 50 kW/m2 compared with 75 kW/m2 produced significantly longer ignition times (with one exception) and lower heat‐release‐related variables as expected. The exception was gypsum board, for which heat release related values were usually higher at 50 kW/m2 than at 75 kW/m2. The specimen thickness effect could not be studied adequately due to the small number of tests conducted. A significant thickness effect was shown for the heat‐release‐related variables but not for time to ignition. The effect, however, was opposite for polyurethane foam in comparison with cellulosic materials. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
4.
Monique Rocha;Bruno Gomes;Amanda Aguiar;Alexandre Landesmann;Nicole Pagan Hasparyk;Romildo Toledo Filho; 《火与材料》2024,48(1):62-78
Bio-based aggregates can be seen as one of the promising alternatives to reduce the environmental impacts of buildings due to their lower carbon footprint and energy efficiency. They have great potential to be incorporated into inorganic matrices and produce insulating materials. However, there is a lack of information about the flammability of these materials. This work presents the results of an experimental investigation of the fire behaviour of bio-based materials. In this study, wastes of bamboo, wood shavings and rice husk were used and were evaluated for their fire performance in the natural state and after treatment in an alkaline solution. The fire reaction properties were determined by using a Mass Loss Cone Calorimeter in order to obtain the parameters of heat release rate (HRR), total heat released (THR), effective heat of combustion (EHC), total mass loss (TML), ignition time (IT) and time of combustion (TC). In addition, physical characterization and thermogravimetric tests were carried out as well as scanning electron microscopy analyses. The results show that the alkaline treatment of the bio-based aggregates is able to reduce the average HRR and the EHC of all bio-aggregates but does not delay the ignition of these materials. Among the residues studied, rice husk presented the lowest peaks and averages of HRR, THR, total mass loss, EHC and time to flameout; however, the ignition occurred faster. 相似文献
5.
This paper investigates the fundamental fire properties of surrogate refuse‐derived fuels (RDF), a class of multicomponent materials characterized by high void fraction, with particles of polydisperse sizes and significant internal porosity. A surrogate RDF was developed to improve the reproducibility of experimental measurements. This surrogate RDF reflects typical municipal solid waste collected in the city of Newcastle, in the state of New South Wales in Australia. The material consists of shredded newspaper, wood, grass and plastic bags, with small amounts of sugar and bread. About 95% of the material passes through 50 mm square screens, as required by ASTM E828 standard for RDF‐3 specification. The experiments presented in this paper were performed with the components of the RDF dried in a forced‐air oven at 103° C, except for grass which was dried under nitrogen. The material was found to be very hygroscopic, requiring special care in handling. The experiments performed in the cone calorimeter were designed to measure the heat release rate, total heat release, time to ignition, time to extinction, effective heat of combustion and formation of CO during the combustion process, as a function of sample thickness, sample density and the magnitude of the imposed radiative heat flux. The thermophysical properties of the surrogate material were either measured (solid density, void space, particle density, particle porosity) or extracted from the published data (heat capacity). The present surrogate RDF material was found to ignite easily, within a few seconds of the imposition of the incident heat flux of 40 kW m?2, and then to reach rapidly the peak heat release rate of 110–165 kW m?2. The deduced values of the critical heat flux, pyrolysis temperature and effective thermal conductivity are 9–10 (±2) kW m?2, 280–310 (±30)° C, and 0.4–0.7 (±0.3) W m?1 K?1, respectively, depending on the material density. The effective heat of combustion of the RDF was estimated as 15.3 MJ kg?1. The material produced 1 kg of CO per 18 kg of dried RDF, mostly during smouldering phase after the extinguishment of the flaming combustion. These results indicate that dried RDF pose significant fire risks, requiring that fire safety systems be implemented in facilities handling RDF. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
6.
The standard cone calorimeter according to ASTM E 1354 and ISO 5660 enables reaction‐to‐fire tests to be performed in ambient atmospheric conditions. A controlled‐atmosphere chamber modifies the standard apparatus in a way that allows tests to be performed in nonambient conditions as well. The enclosed chamber is placed underneath the standard exhaust hood and does not have a closed connection to the hood. With this open arrangement, the exhaust gases are diluted by excess air drawn in from the laboratory surroundings. Heat‐induced changes in the consequential dilution ratio affect the calculation of fire quantities and, when neglected, lead to deviations of up to 30% in heat release rate. The paper introduces a test protocol and equations to calculate the heat release rate taking dilution effects into account. A mathematical correction is shown that compensates for the dilution effects while avoiding extensive mechanical changes in the equipment. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
7.
Cone calorimeter sample size sensitivity and the influence of sample size on the results were studied in order to investigate the possibility to use smaller samples than prescribed by the standard. The influence of the position of the sample on the sample holder of the decreased samples was also studied. Samples of birch plywood, industrial two‐component polyurethane adhesive and polypropylene wax were tested. The results from standard size sample experiments, 100 cm 2, and decreased sample size, 50 and 25 cm2, were compared, in order to investigate the sample size influence on the results. The experiments were performed using an external heat flux of 50kW/ m2. The results show differences between the sample types. The measured heat release rates for plywood and polyurethane adhesive indicate that the sample size is possible to down‐scale, while the polypropylene wax results show the opposite. All sample types and sizes show constant results for the effective heat of combustion, indicating down‐scalability. For in‐house testing and screening of materials, downscaling can be used for most sample types. However, results from experiments carried out with decreased sample size should not be compared to results from experiments executed according to the standard procedure. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
8.
Two test methods for measuring the heat release rate, HRR have been compared on fabric composites used for aircraft interior materials as side‐wall panels. These methods are based on the principles of direct measurement of the convective and radiant heat by thermopiles using an Ohio State University (OSU) calorimeter, and oxygen consumption using a cone calorimeter. It has been observed when tested by standard procedures, cone results at 35 kW/m2 incident heat flux do not correlate with OSU results at the same heat flux. This is because in the cone calorimeter, the sample is mounted horizontally whereas the OSU calorimetric method requires vertical sampling with exposure to a vertical radiant panel. A further difference between the two techniques is the ignition source—in the cone it is spark ignition, whereas in the OSU it is flame ignition; hence, samples in the OSU calorimeter ignite more easily compared to those in the cone under the same incident heat fluxes. However, in this paper we demonstrate that cone calorimetric exposure at 50 kW/m2 heat flux gives similar peak heat release results as the 35 kW/m2 heat flux of OSU calorimeter, but significantly different average and total heat release values over a 2 min period. The performance differences associated with these two techniques are also discussed. Moreover, the effects of structure, i.e. type of fibres used in warp/weft direction and design of fabric are also analysed with respect to heat release behaviour and their correlation discussed. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
9.
The impact of radiant heat flux on ignition and combustion behavior of typical oils (diesel, lubricating oil, and aviation kerosene) was conducted in a cone calorimeter. A circular steel pan with a diameter of 10 cm was used to contain diesel, lubricating oil, and aviation kerosene without water sublayer. Using the standard oxygen consumption method, we obtained ignition time, heat release rate, mass loss rate, extinction coefficient, CO, and CO2 yield, and average specific extinction area was calculated from the extinction coefficient. Janssens' method was adopted in this study to deal with ignition time and radiant heat flux under a 0.55 power rule. Results show that the fitting through Janssens' method is good for ignition time of diesel, lubricating oil, and aviation kerosene and radiant heat flux. Moreover, heat release rate, mass loss rate, and CO/CO2 ratio appear to positively correlate with radiant heat flux, whereas average specific extinction area varies in a certain range. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
10.
11.
Ulf Wickström 《火与材料》2016,40(3):464-471
An analytical closed form formula is presented for explicitly calculating time to reach ignition temperature of semi‐infinite solids exposed to constant incident radiation and gas temperature as for example in the cone calorimeter. The non‐linear boundary condition due to the emitted radiation from the surface being proportional to the surface temperature raised to the fourth power according to the Stephan–Boltzmann law is accurately considered. The formula works for a wide range of the parameter values like the thermal inertia of the solid, the emissivity of the exposed surface and the convective heat transfer coefficient. They are all assumed constant. The new formula contains a single constant coefficient, which has been derived by comparing results obtained by accurate numerical finite element simulations using two different codes, comsol and TASEF , as well as calculations based on a Duhamel superposition scheme. Thus, the formula can be classified as semi‐empirical. It offers a simple approximate solution of a non‐linear problem that requires cumbersome numerical calculation methods to obtain more exact results. Any exact analytical solution is not available. The new method is carefully verified by comparisons with numerical solutions. However, as it is an analysis of well‐defined theoretical methods, any validation and comparisons with test data are not required and has therefore not been made.In comparison with other similar approximation formulas found in the literature, the accuracy as well as simplicity of applying the new formula is outstanding. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
12.
Duy Quang Dao Thomas Rogaume Jocelyn Luche Frank Richard Lucas Bustamante Valencia Sindonie Ruban 《火与材料》2016,40(1):27-47
The thermal degradation of epoxy resin/carbon fiber composites has been performed in ISO 5660 standard cone calorimeter using a piloted ignition. Two kinds of composites that differ by their volume fractions in carbon fiber (56 and 59 vol.%) were tested in this study. The cone calorimeter irradiance level was increased up to 75 kW m?2 to characterize the carbon fiber volume fraction influence on the composite thermal degradation. Thus, main flammability and combustibility parameters were determined and calculated such as mass loss, mass loss rate, ignition time, thermal response parameter, ignition temperature, thermal inertia, and heat of gasification. As a result, all the characteristic parameters for the thermal resistance of composites were decreased when the carbon fiber volume fraction increased. Moreover, the main gaseous products (such as NO, CO, CO2, HCN, H2O, and lightweight hydrocarbons) emitted as well as the oxygen consumption during the composite thermal decomposition were also quantified simultaneously with a portable gas analyzer and a Fourier transform infrared spectrometer. The main species emission yields calculated from the gas analysis results increased slightly when the carbon fiber volume fraction was increased in the initial sample. The epoxy composite was represented as a sooty material with a significant production of soot particles during the combustion process. Furthermore, heat release rate, total heat release, and effective heat of combustion were calculated by using the oxygen consumption calorimetry technique. The results obtained showed that a small increasing of composite carbon fiber amount induced a sharp decrease of heat release rate and total heat release. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
13.
ISO 5660-1 specifies the cone calorimeter method for characterizing the ignition and surface burning behavior of materials. The specimen is irradiated through a square opening in the frame of the specimen holder. The frame is intended to protect the edges of the specimen from irradiation but covers the edges with only a few mm. In tests with products such as composite laminates and sandwich wall panels, the production of pyrolysis gases from the edges and, in many cases, burning have been observed. Early contribution from the edges in the test is not representative for surface burning. A modified specimen holder was developed with a larger specimen size to allow better protection of the edges. The opening for exposure to irradiance of the retainer frame is circular and of the same area as that of the original frame. The distance between the exposed surface and the specimen edges is larger in order to prevent early exposure of edges. Tests using the standard specimen holder resulted in pyrolysis and burning from edges that took place outside of the specimen holder. Comparative tests using the modified specimen holder showed that it prevented the exposure and pyrolysis from edges for an extended time. However, the influence on ignition time and peak heat release due to the increased size of the modified specimen holder has not been characterized fully, and test results should not be used for direct comparison with those of the standard holder. 相似文献
14.
The cone calorimeter, originally designed with an ‘open configuration‘, may be used in combination with a closed‐combustion chamber in order to test specimens in oxygen‐depleted atmospheres (air vitiation effect) or in fuel‐rich combustion (ventilation effect). However, highly under‐ventilated conditions are not achievable, as a consequence of an overconsumption of oxygen due to the incomplete confinement of the flame and imperfections in the air tightness of the combustion volume. In this work, these issues were solved by lowering the combustion zone, in order to fit a 600 mm chimney on the top of the controlled‐atmosphere chamber, and further improving the sealing of the whole setup. n‐Heptane was used as a reference fuel, and its combustion properties were determined in under‐ventilated conditions. The yields of main combustion species correlated well with the global equivalence ratio, for values of Φ up to three. The use of a Fourier‐transform infrared spectrometer allowed further refinement of the total unburned‐fraction composition. The relative concentration of species like methane, ethylene, or acetylene was shown to be relatively constant over the range of under‐ventilated conditions. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
15.
The effects of mineral fillers on the fire retardancy of wood‐polypropylene composites have been studied. Wood‐polypropylene composites containing mineral fillers have been compounded in a conical twin‐screw extruder. A composite manufactured without any mineral filler addition has been used as a reference. The flame resistance properties of the composite materials have been studied using the cone calorimeter. The results show that the introduction of mineral fillers into the wood‐polypropylene composites has a favourable effect on the fire resistance properties of the composite materials. The reaction‐to‐fire properties have been improved according to the fire classification of construction products based on the Euroclass system. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
16.
There is little consensus within the fire science community on interpretation of cone calorimeter data, but there is a significant need to screen new flammability modified materials using the cone calorimeter. This article is the result of several discussions aiming to provide guidance in the use and interpretation of cone calorimetry for those directly involved with such measurements. This guidance is essentially empirical, and is not intended to replace the comprehensive scientific studies that already exist. The guidance discusses the fire scenario with respect to applied heat flux, length scale, temperature, ventilation, anaerobic pyrolysis and set‐up represented by the cone calorimeter. The fire properties measured in the cone calorimeter are discussed, including heat release rate and its peak, the mass loss and char yield, effective heat of combustion and combustion efficiency, time to ignition and CO and smoke production together with deduced quantities such as FIGRA and MARHE. Special comments are made on the use of the cone calorimeter relating to sample thickness, textiles, foams and intumescent materials, and the distance of the cone heater from the sample surface. Finally, the relationship between cone calorimetry data and other tests is discussed. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
17.
This paper deals with the thermal degradation of fir wood in a cone calorimeter under well‐ventilated atmosphere used with a piloted ignition. The thermal and chemical sample decompositions were studied with heat fluxes varying from 15 to 60 kW m?2. With the cone calorimeter results and equations found in literature, the significant parameters of fir wood sample flammability and combustibility were deduced from ignition time (tig), mass loss and gas analysis. These parameters are thermal response parameter, critical heat flux, ignition surface temperature, thermal thickness, mass loss rate, thermal inertia, effective heat of combustion, heat release rate, heat of gasification and others. Moreover, during each experiment, the main gaseous species emissions were continuously and simultaneously monitored. Furthermore, the solid degradation and combustion process for fir wood were described in details. Experimental results from cone calorimeter were compared with data found in literature, and generally, a quite good accordance was found between the both sets of results. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
18.
The aim of this paper is to study the combustion characteristics of loose fibrous cellulosic compounds through cone calorimeter measurements. The challenge in studying loose fibrous materials by cone calorimeter in a reproducible manner is met by optimizing various process parameters such as sample weight, heat flux and grid type. The method is validated using cotton fibres and fabrics with a range of flame retardant properties. Good correlations are obtained between the flame retardant content of samples and the heat release parameters for both the fibres and the fabrics. In addition, fibres from specific cotton cultivars showed statistically significant differences in heat release characteristics. This shows that valuable data concerning the combustion behaviour and the corresponding kinetics of loose fibrous compounds can be successfully gathered using a cone calorimeter. Thus, such data can be exploited to well define future fibre breeding programmes or fibre modification research. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
19.
综述了近几年来乙烯-乙酸乙烯酯共聚物/多壁碳纳米管（EVA/MWNTs）纳米复合材料的研究进展,介绍了其制备方法,详述了其热解行为及阻燃性能（包括热释放速率、引燃时间、成炭性）,并对其阻燃机理进行了深入的讨论。比较了MWNTs、有机黏土、层状双氢氧化物等不同纳米填料的阻燃性能,分析了对MWNTs进行不同处理（包括纯化、使用高密度聚乙烯进行表面涂覆改性、研磨）对相应纳米复合材料的热稳定性及可燃性的影响。 相似文献
20.
为系统地了解电缆在燃烧过程中烟气释放速率以及其与其他参数间的关系,利用锥形量热仪对YJV 4 6电缆的燃烧行为进行了分析。结果表明,电缆在不同外界热流强度下的燃烧行为是不同的。随着热辐射强度的增大,电缆燃烧时的烟气释放速率也随之增大。电缆燃烧时热量的释放滞后于烟气的释放,烟气释放速率随质量损失速率增加而增大。稳定燃烧状态下则表现为烟气释放速率降低,热释放速率增大。 相似文献