1.1 本指南旨在建议初始配置，并在建立DCT所需的适当标准时提供指导，以正确测量本委员会范围内产品的实验室测试方法中的温度。本指南包括近似数字接触温度计（DCT）标准的示例，该标准适用于D02委员会使用的测试方法中的温度测量。 1.2 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3 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。 1.4 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 本指南示例中的信息旨在作为确定测试方法的适当DCT标准的起点，该测试方法测量D02委员会范围内产品的温度相关特性。本指南中的标准示例基于玻璃液体温度计设计组件，即灯泡长度、浸入深度、测量精度、温度计位置等。在测量小型静态样品的温度时，传感器长度、浸入深度和护套直径等参数尤为关键。 这在一定程度上是由于LiG和DCT的导热性不同，然而，设备的其他方面可能会导致不同的结果。例如，当用于测量小静态样品的温度时，适合在搅拌恒温槽中使用的DCT可能会导致测量误差。当样品温度与室温相差40度时，这种差异可以是一度或更大 使用7°C或更高 毫米探头。该误差是由于DCT和LiG温度计的热导率和比热值不同造成的，然而这两种不同装置的其他方面可能会产生不同的结果。 解决这一问题的一种方法是减小DCT护套直径，将护套绝缘到浸没水平以上，并使用实践确定的浸没深度较小的探头 D7962 . 有关选择适当DCT的更多指导，请参阅指南 E2877 . 5.2 当用本指南中注明的DCT替换LiG温度计时，且试验方法未列出任何DCT标准， 用户有责任验证所选DCT的适用性 . 这可以通过比较所选DCT与LiG温度计的测量值并遵循测试程序来实现。 当测量小静态样品的温度时，比较测量尤其重要，因为样品和室温之间存在很大差异。用导热系数较低的玻璃、塑料或管道覆盖DCT探头护套（传感部分除外），可以提高LiG和DCT测量之间的一致性。

1.1 The intent of this guide is to suggest an initial configuration and provide guidance when establishing the appropriate criteria needed for a DCT to correctly measure the temperature in a laboratory test method for products within the scope of this committee. This guide includes examples of the approximate digital contact thermometer (DCT) criteria that was found suitable for measuring temperature in the test methods utilized by Committee D02. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 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. 1.4 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 The information in the examples of this guide are intended to be a starting point for determining the appropriate DCT criteria for a test method that measures a temperature-dependent property of a product within the scope of Committee D02. The criteria examples noted in this guide are based on the liquid-in-glass (LiG) thermometer design components, which are the bulb length, immersion depth, precision of measurement, thermometer position, and so forth. The parameters such as sensor length, immersion depth, and sheath diameter are especially critical when measuring the temperature of small static samples. This is due in part to the difference in thermal conductivity of a LiG vs. a DCT, however other aspects of the devices can contribute to unequal results. For example a DCT that is suitable for use in a stirred constant temperature bath will likely result in measurement errors when used to measure the temperature of a small static sample. This difference can be a degree or more when the sample temperature differs from room temperature by 40 °C or more using a 7 mm probe. This error is due to the difference in thermal conductivity and specific heat value of a DCT and LiG thermometer, however other aspects of the two different devices can contribute unequal results. One way to counter this is by reducing DCT sheath diameter, insulating the sheath above the immersion level, and using a probe that has a small immersion depth as determined by Practice D7962 . For more guidance on selecting an appropriate DCT, see Guide E2877 . 5.2 When replacing a LiG thermometer with a DCT noted in this guide and the test method does not list any DCT criteria, it is incumbent on the user to verify the suitability of the DCT they have selected . This can be done by comparing measurements made with the selected DCT to those of a LiG thermometer and following the test procedure. Comparative measurements are especially important when measuring the temperature of a small static sample where there is a large difference between sample and room temperature. Covering the DCT probe sheath except for the sensing portion with a glass, plastic, or tubing with a lower thermal conductivity can improve the agreement between LiG and DCT measurements.