1.1 本试验方法包括使用便携式折射计测定发动机冷却系统和特殊应用中使用的乙二醇和丙二醇基冷却剂溶液提供的近似防冻保护。 注1: 一些仪器具有甲氧基丙醇冷却剂的补充防冻刻度。其他人则携带一个补充刻度，用于校准硫酸溶液的密度或比重读数，以便使用折射计来确定铅酸蓄电池的充电状态。 1.2 以国际单位制表示的数值应视为标准。SI单位后括号中给出的值仅供参考，不视为标准值。 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。 1.4 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 车辆维修人员通常使用此规程来确定商用乙二醇和丙二醇基冷却液水溶液的冰点，单位为摄氏度或华氏度。当几滴发动机冷却液正确地滴在温度上时，可以使用耐用的手持式折射计直接读取冰点，单位为摄氏度或华氏度- 折射计的补偿棱镜表面。该折射计适用于乙二醇和水溶液，不适用于其他冷却液溶液。 4.2 手持式折射计应在使用前进行校准（请参阅第节 7. )。 4.3 必须注意，对于所测量的乙二醇类型，使用正确的乙二醇冰点刻度。使用错误的乙二醇刻度可能会导致冰点误差达到18华氏度甚至更高。 4.4 乙二醇/丙二醇混合物将导致使用任一冰点刻度进行的冰点测量不准确。

1.1 This test method covers the use of a portable refractometer for determining the approximate freezing protection provided by ethylene and propylene glycol-based coolant solutions as used in engine cooling systems and special applications. Note 1: Some instruments have a supplementary freezing protection scale for methoxypropanol coolants. Others carry a supplemental scale calibrated in density or specific gravity readings of sulfuric acid solutions so that the refractometer can be used to determine the charged condition of lead acid storage batteries. 1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered 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 ====== 4.1 This practice is commonly used by vehicle service personnel to determine the freezing point, in degrees Celsius or Fahrenheit, of aqueous solutions of commercial ethylene and propylene glycol-based coolant. A durable hand-held refractometer is available that reads the freezing point, directly, in degrees Celsius or Fahrenheit, when a few drops of engine coolant are properly placed on the temperature-compensated prism surface of the refractometer. This refractometer is for glycol and water solutions, and is not suitable for other coolant solutions. 4.2 The hand-held refractometer should be calibrated before use (see Section 7 ). 4.3 Care must be taken to use the correct glycol freezing point scale for the glycol type being measured. Use of the wrong glycol scale can result in freezing point errors of 18 and more degrees Fahrenheit. 4.4 Ethylene glycol/propylene glycol mixtures will result in inaccurate freezing point measurements using either freezing point scale.