A two‐step method for predicting time to flashover in room corner test fires using cone calorimeter data

A method to predict time to flashover in ISO 9705 room corner fire tests based on cone calorimeter data is proposed in this paper. The method involves classification of materials and estimation of time to flashover as two steps in sequence. In the first step, the investigated material is classified into discriminating material groups. In the second step, the time to flashover is calculated with a derived formula for the corresponding material group, which contains material density, time to ignition and heat release rate collected from small‐scale experiments. Compared with two existing models, the proposed method has improved the prediction precisions in both the time to flashover and classification of material categories for a wide range of materials. Copyright © 2012 John Wiley & Sons, Ltd.     

Uncertainties in modelling heat transfer in fire resistance tests: A case study of stone wool sandwich panels

Modelling fire performance of building fire barriers would allow optimising the design solutions before performing costly fire resistance tests and promote performance‐based fire safety engineering. Numerical heat conduction analysis is widely used for predicting the insulation capability of fire barriers. Heat conduction analysis uses material properties and boundary condition parameters as the input. The uncertainties in these input parameters result in a wide range of possible model outcomes. In this study, the output sensitivity of a heat conduction model to the uncertainties in the input parameters was investigated. The methodology was applied to stone wool core sandwich panels subjected to the ISO 834 standard fire resistance temperature/time curve. Realistic input parameter value distributions were applied based on material property measurements at site and data available in literature. A Monte Carlo approach and a functional analysis were used to analyse the results. Overall, the model is more sensitive to the boundary conditions than to the material thermal properties. Nevertheless, thermal conductivity can be identified as the most important individual input parameter.     

Mass loss and flammability of insulation materials used in sandwich panels during the pre‐flashover phase of fire

Nowadays, buildings contain more and more synthetic insulation materials in order to meet the increasing energy‐performance demands. These synthetic insulation materials have a different response to fire. In this study, the mass loss and flammability limits of different sandwich panels and their cores (polyurethane (PUR), polyisocyanurate (PIR) and stone wool) are studied separately by using a specially designed furnace. Expanded polystyrene and extruded polystyrene are tested on their cores only. The research has shown that the actual mass loss of synthetic and stone wool‐based cores is comparable up to 300 °C. From 300 °C onwards, the mass loss of PUR panels is significant higher. The mass losses up to 350 °C are 7%, 29% and 83% for stone wool, PIR and PUR respectively, for the influenced area. Furthermore, delamination can be observed at exposure to temperatures above 250 °C for the synthetic and 350 °C for the mineral wool panels. Delamination occurs due to the degradation of the resin between core and metal panels and the gasification of the (PUR) core. The lower flammability limits have been established experimentally at 9.2% m/m (PUR) and 3.1% m/m (PS). For PUR, an upper limit of 74% was found. For PIR and mineral wool, no flammability limits could be established. Copyright © 2017 John Wiley & Sons, Ltd.     

酚醛树脂检测方法与国际标准的对照研究

国内酚醛行业尚未建立国家标准。根据酚醛树脂工业快速发展的特点,酚醛树脂行业应尽快采用统一的相关检验标准。为了同国际标准接轨和提升中国酚醛树脂工业水平,用国内通用的检验方法、仪器设备和ISO标准方法及仪器,检测了树脂中游离酚、水分,粘度和细度等重要项目指标,并进行研究对照。其差距说明必须尽快采用ISO标准的实用价值和意义,为酚醛树脂建标做好前期准备。     

Experimental study of the burner for FAA fire test: NexGen burner

The NexGen (Sonic) burner is the new burner developed by the Federal Aviation Administration, FAA, to replace old oil burners used for the required fire certification tests on power plant‐related materials, as it provides the capability to control both air and fuel flow rates. During a fire test, the burner is supposed to simulate a certain fire condition, so the flame properties should be robust and repeatable. The NexGen burner can achieve this due to the precise fuel and air controls. However, the current calibration criterion (ISO2685:1998 and AC20‐135) may not be good enough to ensure consistent flame properties. In the presented work, the sensitivity of the burner performance to air and fuel flow rate, as measured by the temperature and heat flux for calibration purposes, was studied. Additionally, the influence of the turbulator and the thermocouple size used for flame calibration was also studied. The impact of varying fuel/air ratio and thermocouple sizes was studied by conducting fire tests on aluminum samples, to show the inadequacies in the current calibration standards.     

Temperature effects on the mass flow rate in the SBI and similar heat‐release rate test equipment

In various medium‐to‐large‐scale fire test equipments like the ISO room corner test (RC), and more recently, the single burning item test (SBI) the mass flow rate measurement of the combustion gases plays a key role in the determination of the heat‐release rate and smoke‐production rate. With the knowledge of the velocity profile and the temperature of the flow, the mass flow rate is obtained by measuring the velocity on the axis of the duct. This is done by means of a bi‐directional probe based on the pitot principle. However, due to the variation of the mean temperature and the temperature gradient in any cross section of the duct, introduced by ever changing combustion gas temperatures, the velocity nor the density profile are constant in time. This paper examines the resulting uncertainty on the mass flow rate. Copyright © 2006 John Wiley & Sons, Ltd.     

对比水泥与矿渣基复合掺合料活性的相关性研究

依据GB/T18046—2008中的检测方法,用6种对比水泥对2种矿渣基复合掺合料进行了活性指数检验,研究了对比水泥对矿渣基复合掺合料胶凝活性评定的影响规律。结果表明:复合掺合料活性指数的检验结果因所采用的对比水泥的不同而产生显著的差异,其活性指数与对比水泥胶砂抗压强度之间存在显著的负相关关系。矿渣基复合掺合料专用的化学激发剂对水泥品种来源具有良好的适应性。     

Study on the correlation of lab assay and field test for fouling-release coatings

In this paper, two organisms, diatom and Ulva spore, were employed to evaluate the antifouling performance of five fouling-release (FR) coatings in laboratory, and field test was also assessed. The correlation of lab assay and field test was studied using Spearman's rank correlation test. The results show that the Spearman's coefficient (r_s) between lab assay and field static test is 0.975 (p = 0.005) for diatom and 0.949 (p = 0.014) for Ulva spore respectively, which are significant at the 95% probability level. This indicates that the lab static assays using diatom and Ulva spore have good agreement with field static test. For dynamic performance evaluation, the r_s between diatoms adhesion assay and field dynamic test is 0.894 (p = 0.041) while the r_s for Ulva spore is 0.289 (p = 0.638), indicating the lab dynamic assay with diatom is accordance with the field dynamic test. Therefore, diatom was used to evaluate the performance of coating materials which exhibits the satisfactory correlation and consistency between lab assessment and field test, confirming that diatom is an adapted evaluation organism to evaluate FR coatings.     

Experimental studies on the effect of fire accelerants during living room fires and detection of ignitable liquids in fire debris

Reconstructing the course of a fire and performing chemical analysis of ignitable liquids in fire debris is an important tool to conduct fire investigations in suspected arson cases. Here, a total of five fire tests has been performed to investigate the effect of fire accelerants on the fire development of a room fire and to prove the capability of analytical methods. Different experimental scenarios have been realized (no accelerant, accelerant applied at different positions, and different amounts of fire accelerant). Each test room was equipped with an identical set of living room furnishing. The location and amount of the fire accelerant applied löschen varied in four of five tests. One experiment was carried out without fire accelerant. Fire quantities such as mass loss (of the entire room), gas temperatures (at several locations in the room), and heat release were determined during the experiments, and chemical‐analytical studies were carried out. A headspace solid phase micro extraction procedure, using gas chromatography–mass spectrometry, was used to analyze fire debris samples to potentially detect ignitable liquids. Beside the analysis of fire debris samples, swipe soot samples were analyzed and the detectability of the fire accelerant used was demonstrated. Results show that it is possible to provide evidence of ignitable liquids in soot samples collected from walls. This allows an additional sampling strategy at potential crime scenes, besides taking fire debris samples. Copyright © 2014 John Wiley & Sons, Ltd.     

降解塑料标准化及其生物降解性能测试方法

本文主要介绍降解塑料的定义,降解塑料标准化发展概况,及塑料生物降解性能测试方法。通过分类、综合与比较,指出了原有标准化工作的不完善性和标准生物降解测试方法的局限性。针对全生物降解塑料在短期内无法完全占据市场空间、多元降解机理塑料在一个相当长时期里仍有很大发展余地的现状,作者认为建立多元降解机理塑料的专门标准是必要的。     

絮状试验用白喉和破伤风类毒素标准的国际协作试验

按照国际协作试验计划,本试验用 Ramon 絮状试验方法标化了絮状试验用白喉类毒素和破伤风类毒素国际标准各一批,推荐品即 DIFT 和 TEFT。本试验室标定结果与由13个实验室参加的国际协作标定结果几乎相同。以 DIFT 和 TEFT 为标准,用 Levine-Wyman 的试管絮状试验法和火箭电泳测定了几批白喉类毒素和破伤风类毒素的 Lf,其结果可与 Ramon 方法测定结果相比,证明火箭电泳可用于定量测定类毒素(或毒素)的絮状单位。     

ASI法测定土壤有机质与国标法的相关性研究

对ASI法与GB9834—88测定土壤有机质的结果进行了相关性比较。结果表明,全部样本的ASI法与GB9834-88分析方法的有机质之间存在极显著正相关,相关方程为Y=0．9348x＋0．018（R^2=0．9737＊＊）,两种方法最大相对偏差仅为1.4％。由于ASI方法具有简便、快速和准确的特点,同时减少了铬的污染,是一种较好的土壤有机质测定方法,     

蓄顶温度与火道温度关系模型辨识新方法

针对焦炉火道温度与蓄顶温度关系模型的辨识问题,提出了一种基于区间预估最小二乘法的模型辨识方法.此方法可以有效消除煤气交换给火道温度和蓄顶温度带来的趋势不同的影响.使用置信区间的预计算,能够避免辨识数据紧凑带来的拟合数据准确而物理意义不准确的问题.     

Development of a numerical approach based on coupled CFD/FEM analysis for virtual fire resistance tests—Part A: Thermal analysis of the gas phase combustion and different test specimens

In the present two‐parted study, a numerical approach is shown to consider fire resistance tests in virtual space, including the combustion, thermal analysis of the test specimen, and the deformation process. This part is dealing with the combustion process and thermal analysis of different building materials tested in a fire resistance furnace. Instead of using coupled computational fluid dynamics (CFD)/finite element method simulation for the combustion and thermal heat conduction in the solid, which is commonly used in literature, the present approach considers these transport phenomena in one CFD simulation. This method enables a two‐way coupling between the gas phase and the solid material, where chemical reactions and the release of volatile components into the gas phase can occur (eg, release of water vapour from gypsum). To validate the numerical model, a fire resistance test of a steel door, which is a multilayer construction, and a wall made of gypsum blocks were experimentally and numerically investigated. Due to the chemical reactions inside the gypsum, water vapour is released to the gas phase reducing the flue gas temperature about 80 K. This effect was taken into account using a two‐way coupling in the CFD model, which predicted temperatures in close accordance to the measurement.     

浅谈化学检测实验室内部比对实验方法及结果评价

介绍了化学检测实验室内部比对实验的几种常用方法,并对内部比对实验的评价方法进行了较为系统的研讨。样品标准值无置信区间时,可选择检测方法的再现性限进行评价;样品标准值的不确定度已知时,可采用E值进行评价;有2组测定数据,每组数据有多个平行测定结果时,可使用t检验法进行评价;对于多组测定数据,每组数据有2个平行测定结果时,可用z比分数法进行评价。     

ISO527-1/2新旧版本标准的对比研究

2012年,ISO标准化组织发布了最新的ISO 527-1/2:2012文件,替代原有的1993版本。经解读,IS0 527-1:2012总则在结构上有轻微的改变,而在内容上主要是对术语定义、测试速度等进行了修订,ISO 527-2:2012试验条件中新增了1A型样条的标距75 mm。术语的修订、测试速度的多样性选择、试验条件的改变等都将会对塑料材料的性能测试结果产生影响。     

煤粉工业锅炉运行数据与供料参数的相关性研究

供料参数的定量测量是锅炉实现自动调节的重要前提。目前直接测量设备受浓度测量范围、成本等因素影响,对工业锅炉适用性有限,而锅炉现有各传感器的部分数据与供料系统关系密切。为了探究根据传感器数据计算供料参数的可行性,以1 Hz频率收集了天津华苑1台58 MW锅炉的传感器数据,在控制其他变量的条件下筛选中间仓重量、一次风总压、锁气阀转速、炉膛压力、烟气氧含量等与供料相关的数据,通过最小二乘法、决定系数等分析方法,定量计算变量绝对值、标准差与供料参数的关系。结果表明,当中间仓进料阀关闭时,可通过中间仓称重以高准确度计算供料器300 s内的平均供料量;使用供料锁气阀转速计算供料量,基于锁气阀填充率和填充密度为定值的假设,低转速下供料曲线符合该假设。但随着锁气阀转速提高,供料量随转速的增长速率以二次曲线规律边际递减,且递减规律存在个体差异;一次风总压计算供料量属于差压法,用于计算供料量时,调整后的决定系数RAdj2>0.98,具有较高的准确性,但需要根据每台设备的累计运行数据计算系数k;炉膛负压波动可较好反映供料波动,但准确性低于使用一次风总压,取样时间为30 s时,供料量标准差-炉膛压力标准差RAdj2达到最大值,为0.890 1;供料量-耗氧量的RAdj2在取样时间200 s时达到最大值0.296 1,供料量标准差-耗氧量标准差RAdj2在取样时间10 s时达到最大值0.640 8,说明耗氧量用于推断供料波动的可靠性中等,推断供料量的可靠性较差,这可能与该锅炉煤粉的掺混比例不稳定使单位质量煤粉热值波动较大有关。     

New method for the determination of surfactant solubility and partitioning between CO2 and brine

A novel method is presented for measuring solubility in supercritical CO₂ (scCO₂), which can be used in conjunction with traditional cloud point measurements to obtain information directly on the soluble portion of a given sample and, ultimately, a much more informative data set. In this method, surfactant from a known amount of CO₂ solution was transferred into an aqueous solution and the surfactant concentration of the aqueous solution was measured directly by HPLC (high-performance liquid chromatography). In this work, the partitioning of a series of 2-ethylhexanol (2-EH) alkoxylate surfactants among an aqueous phase (water or brine) and scCO₂ as a function of electrolyte concentration, temperature, and pressure was also investigated. Surfactant partition coefficient was determined based on the reduction of HPLC measured surfactant concentration in the aqueous phase due to surfactant partitioning into CO₂. An understanding of surfactant partitioning between brine and scCO₂ is particularly important in the design of CO₂ foam processes, particularly for surfactant stabilized foam in subsurface systems, where it can affect surfactant transport and foam propagation. In general, the solubility in scCO₂ increased with pressure and decreased with temperature. The partitioning of the surfactants between CO₂ and water phases was almost proportional to pressure, and decreased as temperature increased, where the latter held more sensitivity. The partition coefficient was very sensitive to surfactant formula. For the 2-EH-PO5-EO_x series, the partition coefficient between scCO₂ and the aqueous phase increased with decreasing EO content.     

多元回归分析在地球化学和地球物理常规测井资料的研究

在测井测得一系列的数据以后,我们需要的并不是全部的数据,而是需要提取一种岩石的几种物性或者是提取几种岩石的一种物性对比,以了解各种岩石的岩性特征,或是通过岩性来判断岩石的种类,利用这些岩性参数,建立它们之间的回归关系式,利用回归关系式反推或预测地层中一定深度元素和矿物的含量,通过一系列的研究我们可以清楚看到地下一段深度的地质体的地质特征,进而达到我们研究的目的。     

Effect of temperature on the correlation between the oxidative-bleach fading observed in the ISO 105;C09 test and that after multiple domestic laundering cycles for dyed wool fabrics

Using a set of dyed wool fabrics, the oxidative-bleach fading observed in ISO 105;C09 tests carried out at 40, 50 and 60 °C have been compared with that after 20 domestic wash cycles. It has been shown that the C09 test carried out at 50 °C is suitable for predicting the fading encountered after repeated domestic laundering.