1.1 这些测试方法包括测量直流绝缘电阻、体积电阻和表面电阻的直流程序。根据这些测量值以及试样和电极的几何尺寸，可以计算电绝缘材料的体积电阻率和表面电阻率，以及相应的电导率和电导率。 1.2 这些试验方法不适用于测量中等导电材料的电阻/电导。使用测试方法 D4496号 评估此类材料。 1.3 这些测试方法描述了测量电阻（或电导）的几种通用替代方法。 通过使用适用于特定材料的标准ASTM测试方法，可以最合适地测试特定材料，该方法定义了电压应力极限和有限通电时间，以及样本配置和电极几何形状。这些单独的特定测试方法将更好地定义测定的精度和偏差。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 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《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 5.1 绝缘材料用于将电气系统的部件彼此隔离和与地面隔离，并为部件提供机械支撑。为此，通常希望绝缘电阻尽可能高，与可接受的机械、化学和热一致- 抵抗性能。由于绝缘电阻或电导结合了体积和表面电阻或电导，当试样和电极的形状与实际使用中要求的形状相同时，其测量值最有用。表面电阻或电导随湿度变化迅速，而体积电阻或电导变化缓慢，在某些情况下总变化较大。 5.2 电阻率或电导率用于间接预测某些材料的低频介电击穿和损耗因子特性。电阻率或电导率通常用于间接测量: 含水量、固化程度、机械连续性或各种类型的劣化。这些间接测量的有用性取决于通过支持理论或实验研究建立的相关性程度。表面电阻的降低会导致由于电场强度降低而导致介质击穿电压升高，或者由于受力面积增加而导致介质击穿电压降低。 5.3 所有介电电阻或电导率取决于通电时间的长度和施加电压的值（除通常的环境变量外）。 为了使电阻或电导的测量值有意义，必须知道并报告这些值。在电气绝缘材料行业内，形容词“视在”通常用于在任意选择的通电时间条件下获得的电阻率值。看见 X1.4 . 5.4 根据电阻和尺寸数据计算体积电阻率或电导率，以帮助设计特定应用的绝缘体。研究表明，电阻率或电导率随温度和湿度而变化 ( 1- 4. ) . 4. 在设计工作条件时，必须了解这些变化。 体积电阻率或电导率测定通常用于检查绝缘材料的均匀性，无论是在加工方面，还是在检测影响材料质量且不易通过其他方法检测到的导电杂质方面。 5.5 体积电阻率大于10 21 Ω·cm（10 19 Ω·m），根据在通常实验室条件下测试的样本获得的数据计算，考虑到常用测量设备的局限性，其有效性值得怀疑。 5.6 表面电阻或电导无法准确测量，只能近似测量，因为测量中总是涉及一定程度的体积电阻或电导。 测量值也受到表面污染的影响。表面污染及其累积速度受许多因素的影响，包括静电电荷和界面张力。这些反过来会影响表面电阻率。当涉及污染时，表面电阻率或电导率被认为与材料特性有关，但在通常意义上不是电绝缘材料的材料特性。

1.1 These test methods cover direct-current procedures for the measurement of dc insulation resistance, volume resistance, and surface resistance. From such measurements and the geometric dimensions of specimen and electrodes, both volume and surface resistivity of electrical insulating materials can be calculated, as well as the corresponding conductances and conductivities. 1.2 These test methods are not suitable for use in measuring the electrical resistance/conductance of moderately conductive materials. Use Test Method D4496 to evaluate such materials. 1.3 These test methods describe several general alternative methodologies for measuring resistance (or conductance). Specific materials can be tested most appropriately by using standard ASTM test methods applicable to the specific material that define both voltage stress limits and finite electrification times as well as specimen configuration and electrode geometry. These individual specific test methodologies would be better able to define the precision and bias for the determination. 1.4 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. 1.5 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 Insulating materials are used to isolate components of an electrical system from each other and from ground, as well as to provide mechanical support for the components. For this purpose, it is generally desirable to have the insulation resistance as high as possible, consistent with acceptable mechanical, chemical, and heat-resisting properties. Since insulation resistance or conductance combines both volume and surface resistance or conductance, its measured value is most useful when the test specimen and electrodes have the same form as is required in actual use. Surface resistance or conductance changes rapidly with humidity, while volume resistance or conductance changes slowly with the total change being greater in some cases. 5.2 Resistivity or conductivity is used to predict, indirectly, the low-frequency dielectric breakdown and dissipation factor properties of some materials. Resistivity or conductivity is often used as an indirect measure of: moisture content, degree of cure, mechanical continuity, or deterioration of various types. The usefulness of these indirect measurements is dependent on the degree of correlation established by supporting theoretical or experimental investigations. A decrease of surface resistance results either in an increase of the dielectric breakdown voltage because the electric field intensity is reduced, or a decrease of the dielectric breakdown voltage because the area under stress is increased. 5.3 All the dielectric resistances or conductances depend on the length of time of electrification and on the value of applied voltage (in addition to the usual environmental variables). These must be known and reported to make the measured value of resistance or conductance meaningful. Within the electrical insulation materials industry, the adjective “apparent” is generally applied to resistivity values obtained under conditions of arbitrarily selected electrification time. See X1.4 . 5.4 Volume resistivity or conductivity is calculated from resistance and dimensional data for use as an aid in designing an insulator for a specific application. Studies have shown changes of resistivity or conductivity with temperature and humidity ( 1- 4 ) . 4 These changes must be known when designing for operating conditions. Volume resistivity or conductivity determinations are often used in checking the uniformity of an insulating material, either with regard to processing or to detect conductive impurities that affect the quality of the material and that are not readily detectable by other methods. 5.5 Volume resistivities above 10 21 Ω·cm (10 19 Ω·m), calculated from data obtained on specimens tested under usual laboratory conditions, are of doubtful validity, considering the limitations of commonly used measuring equipment. 5.6 Surface resistance or conductance cannot be measured accurately, only approximated, because some degree of volume resistance or conductance is always involved in the measurement. The measured value is also affected by the surface contamination. Surface contamination, and its rate of accumulation, is affected by many factors including electrostatic charging and interfacial tension. These, in turn, affect the surface resistivity. Surface resistivity or conductivity is considered to be related to material properties when contamination is involved but is not a material property of electrical insulation material in the usual sense.