1.1 本指南介绍了两种商用水三相点电池的性质（A型和B型，请参阅 图1 )并提供了一种用于制备电池以实现水三相点并校准温度计的方法。讨论了电池所用玻璃的制备条件和类型。给出了确保合格电池和待合格电池完整性的测试。还描述了处理电池以避免破损的注意事项。 图1 两种常用的三点式水电池（A型和B型）的配置，带有准备在冰/水平衡温度下进行测量的冰套。将细胞浸入控制在接近0.01的冰浴或水浴中使用 °C（参见 5.5 ) 1.2 讨论了静水压力对水三相点电池温度的影响。 1.3 针对自加热和静水压力的影响，调整观察到的SPRT电阻读数的程序如所述 附录X1 和 附录X2 。 1.4 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》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 4. 1. 本指南介绍了将水三相点池投入使用以及将其用作温度计校准中的参考温度的程序。 4.2 所获得的参考温度是纯水的基本状态，即共存的固相、液相和气相之间的平衡。 4.3 电池需要进行鉴定，但不需要校准。单元格可以被限定为能够表示基本状态（请参阅 4.2 )通过与已知历史的类似合格细胞库进行比较，它可能是合格的，并且其制造商记录了资格。 4.4 ITS-90上合格的水三相点池的温度恰好为273.16 K，除非对同位素成分进行了校正（参考 附录X3 )。 4.5 合格细胞的持续准确性取决于持续的物理完整性。 这可以通过第节中描述的技术进行验证 6. 。 4.6 根据制备方法的不同，本标准中描述的商用三点水电池能够实现±0.1 mK和±0.05 mK之间的扩展不确定度（k=2）。应遵循规定的测量程序，以达到这些不确定度水平。 4.7 商业上可获得的未知同位素组成的三点水电池应能够实现不大于0.25mK的扩展不确定性（k=2），这取决于实际的同位素组成 ( 3. ) 这些类型的电池可以在这个较大的不确定性值下使用。

1.1 This guide covers the nature of two commercial water triple-point cells (types A and B, see Fig. 1 ) and provides a method for preparing the cell to realize the water triple-point and calibrate thermometers. The qualifications concerning preparation and the types of glass used for a cell are discussed. Tests for assuring the integrity of a qualified cell and of cells yet to be qualified are given. Precautions for handling the cell to avoid breakage are also described. FIG. 1 Configurations of two commonly used triple point of water cells, Type A and Type B, with ice mantle prepared for measurement at the ice/water equilibrium temperature. The cells are used immersed in an ice bath or water bath controlled close to 0.01 °C (see 5.5 ) 1.2 The effect of hydrostatic pressure on the temperature of a water triple-point cell is discussed. 1.3 Procedures for adjusting the observed SPRT resistance readings for the effects of self-heating and hydrostatic pressure are described in Appendix X1 and Appendix X2 . 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 ====== 4.1 This guide describes a procedure for placing a water triple-point cell in service and for using it as a reference temperature in thermometer calibration. 4.2 The reference temperature attained is that of a fundamental state of pure water, the equilibrium between coexisting solid, liquid, and vapor phases. 4.3 The cell is subject to qualification but not to calibration. The cell may be qualified as capable of representing the fundamental state (see 4.2 ) by comparison with a bank of similar qualified cells of known history, and it may be so qualified and the qualification documented by its manufacturer. 4.4 The temperature to be attributed to a qualified water triple-point cell is exactly 273.16 K on the ITS-90, unless corrected for isotopic composition (refer to Appendix X3 ). 4.5 Continued accuracy of a qualified cell depends upon sustained physical integrity. This may be verified by techniques described in Section 6 . 4.6 The commercially available triple point of water cells described in this standard are capable of achieving an expanded uncertainty (k=2) of between ±0.1 mK and ±0.05 mK, depending upon the method of preparation. Specified measurement procedures shall be followed to achieve these levels of uncertainty. 4.7 Commercially-available triple point of water cells of unknown isotopic composition should be capable of achieving an expanded uncertainty (k=2) of no greater than 0.25 mK, depending upon the actual isotopic composition ( 3 ) . These types of cells are acceptable for use at this larger value of uncertainty.