A Quantitative Infrared Imaging System for In Situ Characterization of Composite Materials in Fire Tests

A novel non-intrusive measurement system based on quantitative infrared imaging has been designed and developed specifically for the study of composite plates submitted to fire. The system consists of two synchronized infrared cameras that image both sides of the sample during a fire test, providing surface temperature maps spatially corregistered. Flame effects on measured temperature are minimized through selection of a spectral band with near negligible infrared absorption-emission (wavelength centre 9585 nm, full width at half maximum 135 nm), as well as software post-processing. An ad hoc experiment has shown that this procedure retrieves surface temperatures with an uncertainty of \(\pm 5\) K, compared to a systematic error larger than 60 K for a classic thermographic measurement. Surface emissivities of both sides of the sample are measured and included in the retrieval procedure. By adding a flash lamp, the system implements an adaptation of the classical Parker’s flash method to thermally thick samples, providing also a map of thermal diffusivities along the sample both before and after the burning. In the region most degraded by fire, the effective thermal diffusivity is reduced approximately one order of magnitude as compared to the pre-test value (from 5.9 × 10^?7 m² s^?1 to 0.5 × 10^?7 m² s^?1). Several composite samples have been analysed while exposed to fire in different conditions, showing that thermal diffusivity after the burning shows a strong correlation with the local maximum temperature reached during the test. More precisely, in the temperature range between \(\sim \)325 and 350\(^{\circ }\)C a drastic change in diffusivity seems to takes place, in a way that suggest a phase change.     

火灾混凝土建筑物红外热像鉴定技术与案例

根据红外热像检测原理,采用红外热像仪检测火灾损伤的钢筋混凝土结构,分析其受火温度、强度损失及损伤深度,并综合评价其损伤等级。现场检测实践表明,钢筋混凝土结构火灾损伤的红外热像检测与评估,可快速获取比较全面翔实的建筑物火灾损伤资料,从而为修复加固工程提供科学可靠的依据。     

岩土热物理参数测定

随着地铁项目的逐步增多,岩土热物理参数逐步被广泛关注,特别是DRE-2C导热系数测试仪,目前已被国内多家单位引用于测定岩土的热物理参数指标。研究分析了采用DRE-2C导热系数测试仪及BRR比热容测试仪测试岩土热物理参数的测试方法及流程,以期为同行提供一些有益的参考。     

A Review on Structural Fire Tests of Two-Way Composite Floors

Fire Technology - The utilisation of composite floor systems in modern construction allows for building large floor areas with efficient use of material and labour. The efficiency of this flooring...     

红外热成像技术在建筑节能检测中的应用

红外热成像法在建筑工程领域应用前景十分广阔,介绍了红外热成像的原理、检测方法和近年来在建筑节能检测领域的应用,并对红外热成像检测技术的应用前景进行了分析与展望.     

应用红外热成像技术检测饰面花岗岩的粘贴质量

对红外热像法在建筑外墙饰面工程中应用的可行性及工作原理、应用方法等进行了论述。现场检测案例表明,红外热像法检测建筑外墙饰面花岗岩,可大面积、快速地获得比较翔实的粘贴质量状况,为修复加固提供科学依据。     

Assessment of Physical Phenomena Associated to Fire Doors During Standard Tests

Fire doors are widely used in buildings. These doors act as delimiters or fire enclosures and require specific fire resistance. However, in general, the thermal and mechanical properties of materials change substantially upon exposure to high temperatures. Therefore, in order to optimize the performance of fire doors, we require adequate knowledge about the fire-related behavior of the materials used for making these doors. In this paper, we present an analysis of the thermal behavior of fire doors EI2-60 subjected to standard tests in a furnace. Infrared thermography and traditional techniques of passive measurements involving the use of thermocouples were used in this study. The main physical phenomena occurring in the considered compartmentalized elements when subjected to high temperatures were characterized experimentally. These experiments were carried out on two fire doors that open into and away from the furnace; these are the only two types of configurations used in buildings. Moreover, the thermal behaviors of several component materials of the fire doors were investigated. The use of infrared thermography during a furnace test allowed us to observe the separation evolution between wool and sheet metal, enabling the appearance of convection currents. In this study, we analyzed the different phenomena occurring in a fire door during a furnace test. The temperature-dependent behavior of the unexposed side of the fire door was characterized into three sections. During the furnace test, the separation between the component materials of the door was found to increase; this increase in turn led to an increase in the heat transfer coefficient and simultaneously enabled the appearance of convection currents in this closed space. These phenomena were found to have a direct effect on the temperature-dependent behavior of the unexposed side of the fire door.     

分光光度计及红外光谱仪在建筑材料检测领域的应用

介绍了分光光度计和红外光谱仪在常规领域的检测应用,重点对分光光度计和红外光谱仪在建筑材料的化学分析、玻璃陶瓷和隔热涂料等方面的检测应用进行了分析和探讨。     

Thermal Response of Composite Materials to Elevated Temperatures

Different decomposition models of varying complexity were developed to predict the heat and mass transfer through charring/reinforced materials that are undergoing decomposition. Models included a heat conduction based model, decomposition model neglecting internal pyrolysis gas convection, and decomposition model with internal convection. Experimental methods were developed to measure the decomposition kinetic parameters and thermal properties required for input into the different models. Model results compared well with experimental data. Agreement between the heat conduction model was further improved by modifying the heat of decomposition to account for the internal convection effects.     

考虑结构和热力学参数的钢梁抗火性能预测

给出预测标准火灾条件下钢梁耐火时间的公式。首先,根据热力学特性找出影响钢梁抗火性能的关键参数,然后将其划分为结构参数或热力学参数。通过完全耦合热力学数值分析方法,研究发生大变形前各参数对耐火性能的影响。在进行广泛的参数分析前,利用试验结果验证了数值模拟的准确性。通过多元线性回归分析,得到各种设计条件下钢梁抗火时间的预测公式。统计分析表明,所提出的公式是有效的。详细说明了该公式在实际消防设计中的应用,也介绍了该公式的优点。     

红外热成像检测技术在工程领域中的应用

介绍红外热成像检测技术在电力系统、汽车工业等领域中的应用,并结合该检测技术的优点,探讨红外热成像检测技术在沥青路面施工过程中的应用,对沥青混合料的温度检测,判断沥青混合料在施工作业过程中的温度离析情况,制定合理的施工方法,控制作业质量.     

相变微胶囊/加气混凝土复合材料的热工性能

通过免蒸压法制备加气混凝土(AC),并在制备过程中加入以RT25石蜡为相变材料的相变微胶囊(MPCMs),得到相变微胶囊/加气混凝土复合材料(以下简称复合材料).在17、40℃下测试复合材料的导热系数和比定压热容,研究了这些参数与相变微胶囊掺量的关系,同时计算出复合材料的蓄热系数,据此评价了其蓄热性能.结果表明:随着相变微胶囊掺量的增加,复合材料的导热系数和比定压热容均呈现先增加后降低的趋势;当相变微胶囊掺量为1.0%时,复合材料具有最好的蓄热性能,较不掺相变微胶囊的对照组增强74%,蓄热系数可达3.35W/(m^2·K).     

红外热成像中医可视化研究进展

红外热成像可以作为中医望诊的延伸,可以分辨阴阳、寒热、表里、虚实,通过脏腑、经络、三焦的热态分布变化辅助辨证,尤对寒热表现突出证候的疗效判定提供直观的数据支持。但亦有不足之处:在疾病诊断、体质辨识上缺少大样本数据支持;缺乏公认的正常人群热态图形表现;没有较好的自动化分析软件支持后续数据分析,使得后续研究工作较为繁琐。     

Image Frequency Analysis for Testing of Fire Service Thermal Imaging Cameras

A growing number of first responders are purchasing infrared cameras (thermal imagers). Thermal imagers provide critical information for many firefighting operations: size up, tracking of fire growth, location of victims and egress routes, overhaul, etc…. Although thermal imagers have proven to be useful tools for the fire service over the past 10–15 years, there is no existing comprehensive performance standard for thermal imagers used in fire service applications. A suite of thermal imager performance metrics and test methods is being developed for possible inclusion in a proposed standard on thermal imagers for the fire service. The following goals apply to two of the imaging performance metrics in this suite: to explore the feasibility of a new spatial resolution metric and test method, the Random Modulation Transfer Function (MTF); and to transfer the essential characteristics of complex fire scene images to a thermal target for the effective temperature range test using image frequency content analysis. Images of humans standing in an upright position at varying distances from the thermal imager under test and wearing either street clothes or turnout gear were analyzed for frequency content. These data were then used to determine the frequency of a bar target for the bench-scale effective temperature range test.     

红外热像技术在建筑节能诊断中的应用研究

随着发展低碳经济和建设节约型社会日益受到重视,节能减排也成为社会关注的热点。而建筑节能又是节能减排的一个重要领域,发展空间巨大。由于我国建筑节能起步较晚,许多建筑没有做节能措施或措施不到位,需要对其进行节能诊断,为建筑的节能改造提供依据。对于新建建筑往往由于施工或设计的不合理,会产生一些围护结构的热工缺陷,导致保温、隔热效果不能达到要求,此时也需要对其进行节能诊断,判断节能效果是否满足要求,指导建筑的设计和施工等。目前,建筑节能检测和诊断有许多方法,红外热像技术是其中最为简单、直接、方便的。本文主要介绍红外热像技术的原理和在建筑节能诊断中的应用,结合现场检测的温度分布情况,对测量建筑进行热工分析和节能诊断,判断其节能效果。     

建筑节能缺陷检测红外热成像法浅析

随着科学技术的进步,建筑节能缺陷的检测技术日渐成熟,方法趋向多样化。红外热成像法是检测建筑节能缺陷的一个重要方法,建筑师普遍应用红外热成像法检测建筑的节能效果,这是建筑节能缺陷技术的一个新突破。     

建筑围护结构缺陷的红外热成像检测案例解析

红外热成像技术近年来在建筑围护结构缺陷检测中的应用逐步增多。为了探索其在建筑工程检测中的适用性,我们进行了实验以及现场探测,发现一些在大连特殊气候条件下常见缺陷的红外图像,并结合施工图纸的查阅,深入分析围护结构的材料、构造形式等,借以确定围护结构缺陷性质和成因,进而为围护结构的改造及维修提供有效的参考建议。     

红外热成像技术在建筑节能检测中的应用

文章对红外热成像仪检测技术在建筑节能应用现状做了简要介绍,通过红外热像检测诊断分析的实例,概括地介绍了红外热像技术在建筑领域中的节能保温方面的应用.     

红外热成像技术在建筑节能检测中的应用

介绍了红外热成像技术的基本原理,总结了近年来红外热戍像技术在建筑节能研究和实践中的应用,特别通过大量翔实的图片资料阐述了红外热成像技术在热传导损失、热对流损失、受潮、渗漏、外墙饰面质量检测中的应用,供有关质量检测和标准制订等部门在进行相关栓测和标准编撰时参考。     

基于不同工艺需求的热工测量参数确定

以系统平衡、主机设备运行状况、系统能耗等为标定单元进行分析,确保企业技术人员或测量人员所测的参数全面而可靠,真实地反映生产状况,满足不同企业的不同工艺需求。