1.1 本规程包括使用热流计装置测量小型平板绝热试样的稳态热传导特性。 1.2 本规程提供了与试验方法一起使用的补充程序 第518页 用于测试小样本。本规程仅限于小试样，在所有其他细节中，还应符合试验方法的要求 第518页 申请 1.3 这种做法的特点是小试样的横向尺寸小于用于测量热流的热通量传感器的横向尺寸。试验方法中的程序 第518页 应用于横向尺寸等于或大于热通量传感器横向尺寸的试样。 注1: 样本尺寸的下限通常由用户针对其特定材料确定。 例如，参考。 ( 1. ) 2. 对于具有0.15m×0.15m热通量传感器的0.3m×0.3m热流量计装置，对于几种不同的绝热材料，确定了0.1m×0.1m的试样尺寸下限。 1.4 这种做法仅用于研究目的，特别是在无法获得较大样本时。本规程不得与试验方法一起使用 第518页 产品认证测试；符合ASTM规范；或符合法规或建筑规范要求。 1.5 以国际单位制表示的数值应视为标准。本规程不包括其他计量单位。 1.6 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 5.1 在新产品开发过程中，或在法医调查（即故障分析）中无法收集较大样本时，对小绝缘样本进行导热性测量非常重要 ( 1. , 2. ) . 5.2 最近已经开始了许多研究项目，以开发具有极高热阻（大于83（mK）/W）的绝缘材料。从提高单窗格玻璃/多层玻璃系统热性能的涂层到开发建筑围护结构的新型隔热产品等项目正在进行中 ( 1- 4. ) 所有这些项目在开发新材料技术方面都遇到了困难，这是因为与测量高热阻材料的小截面（约0.025m×0.025m）的热导率相关的困难。随着新材料的开发，每个试样的尺寸都会影响开发成本。大多数现有的测试设备和方法不符合研究人员的需要；该设备需要大的样本尺寸，耗时且生产成本高。 5.3 本规程提供了一个标准化程序，以实现小型隔热材料试样的热特性。准确、可靠的热计量，以评估新绝缘材料的热性能，如新型极低导热率（<0。 01 W/（m K））纳米材料或生物基泡沫绝缘材料，在小材料样品部分，以及最低数据分析要求是本实践的预期结果。 5.4 试样和热通量传感器的面积比对本实践中获得的结果的不确定性有重大影响。随着试样面积的减小，该比率减小，总热流的较小百分比与未知试样相关。来自文献的信息 ( 4. ) 结果表明，一些热流量计设备（通常在商业上不可用，仅由研究实验室使用）可以进行修改，以更换热通量传感器，从而可以部署不同尺寸的传感器。观察结果见 图2 是从这种热量的测量中获得的- 为了更换热通量传感器而修改的流量计装置。 图2 证明了试样面积与热通量传感器面积之比对使用本规程测量热导率精度的重要性。本练习不是本练习的必需部分 图2 仅供参考。 图2 从0.010 m获得的数据集示例 2. （即，0.10m×0.10m）热通量传感器（热流），探索不同厚度（0.005m、0.010m和0.020m）的不确定性（即，全尺寸XPS样品和置于掩模内的较小XPS样品之间的差异）

1.1 This practice covers the measurement of steady state thermal transmission properties of the small flat slab thermal insulation specimen using a heat-flow-meter apparatus. 1.2 This practice provides a supplemental procedure for use in conjunction with Test Method C518 for testing a small specimen. This practice is limited to only small specimens and, in all other particulars, the requirements of Test Method C518 apply. 1.3 This practice characterizes small specimens having lateral dimensions less than the lateral dimensions of the heat flux transducer used to measure the heat flow. The procedure in Test Method C518 shall be used for specimens having lateral dimensions equal to or larger than the lateral dimensions of the heat flux transducer. Note 1: The lower limit for specimen size is typically determined by the user for their particular material. As an example, Ref. ( 1 ) 2 established a lower limit for specimen dimensions of 0.1 m by 0.1 m for several different thermal insulation materials for a 0.3 m by 0.3 m heat-flow-meter apparatus having a heat flux transducer 0.15 m by 0.15 m. 1.4 This practice is intended only for research purposes, in particular, when larger specimens are unavailable. This practice shall not be used in conjunction with Test Method C518 for certification testing of products; compliance with ASTM Specifications; or compliance with regulatory or building code requirements. 1.5 The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this practice. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 Thermal conductivity measurements on small insulation specimens are important during new product development processes or when larger specimens cannot be collected during forensic investigation (that is, failure analysis) ( 1 , 2 ) . 5.2 Numerous research projects have recently been initiated to develop insulation materials that have very high thermal resistivities (greater than 83 (m K)/W). Projects ranging from coatings to improve the thermal performance of single pane/layer glazing systems to the development of novel insulation products for building envelopes are being undertaken ( 1- 4 ) . All these projects have struggled in the development of new material technologies due to the difficulty associated with the measurement of thermal conductivity of small sections (approximately 0.025 m by 0.025 m) of high thermal resistance materials. As new materials are being developed, the size of each test specimen impacts the cost of development. Most of the existing test equipment and the methods do not align with the researcher’s need; the equipment requires a large specimen size is time consuming, and expensive to produce. 5.3 This practice provides a standardized procedure to enable the thermal characterization of small specimens of insulation materials. Accurate, and reliable thermal metrology to assess thermal properties of new insulation materials, such as novel very low thermal conductivity (< 0.01 W/ (m K)) nanomaterials or bio-based foam insulations, in small material sample sections, and minimal data analysis requirements is the desired outcome of this practice. 5.4 The ratio of the area of the specimen and the heat flux transducer has a significant impact on the uncertainty of the results obtained from this practice. As the specimen area decreases this ratio decreases, a smaller percentage of the total heat flow is associated with the unknown specimen. Information from the literature ( 4 ) shows that some heat-flow-meter apparatus, generally not available commercially and used by the research laboratories only, can be modified to change out the heat flux transducer so that transducers of varying sizes can be deployed. The observations presented in Fig. 2 were obtained from the measurements done by such a heat-flow-meter apparatus that was modified to change out the heat flux transducer. Fig. 2 demonstrates the significance of the ratio of the area of the specimen and the heat flux transducer on the accuracy of the thermal conductivity measurement using this Practice. This exercise is not a required part of this Practice and Fig. 2 is for information only. FIG. 2 Example of a data set obtained from 0.010 m 2 (that is, 0.10 m × 0.10 m) heat flux transducer (heat flow) exploring the uncertainty (that is, difference between full size XPS specimen and smaller XPS specimen placed inside the mask) of varying thicknesses, 0.005 m, 0.010 m, and 0.020 m