1.1 本试验方法描述了使用光学装置的自动仪器测定厚度为40 mm的透明石油产品和生物柴油的浊点。 1.2 本试验方法涵盖以下温度范围: −60 °C至 +49 °C，温度分辨率为0.1 °C，然而，1997年实验室间合作试验计划中包含的温度范围仅涵盖以下温度范围: –56 摄氏度至+34度 °C。 1.3 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。 1.4 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 对于石油产品和生物柴油，浊点是其在某些应用中效用的最低温度指数。足够数量的蜡晶体可以堵塞某些燃油系统中使用的滤清器。 5.2 石油混合操作需要精确测量浊点。 5.3 该试验方法可以确定蜡晶体形成的试样温度，在该温度下，蜡晶体可以充分观察到分辨率为0的云。 1. °C。 5.4 该测试方法提供的结果在四舍五入到下一个较低整数时与测试方法等效 D2500 . 提到 12.2 . 5.5 该测试方法比测试方法更精确 D2500 . 注1: 根据实验室间检查，发现该试验方法的再现性比试验方法更精确 D2500 .

1.1 This test method covers the description of the determination of the cloud point of petroleum products and biodiesel fuels that are transparent in layers 40 mm in thickness, by an automatic instrument using an optical device. 1.2 This test method covers the range of temperatures from −60 °C to +49 °C with temperature resolution of 0.1 °C, however, the range of temperatures included in the 1997 interlaboratory cooperative test program only covered the temperature range of  –56 °C to +34 °C. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 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 For petroleum products and biodiesel fuels, the cloud point is an index of the lowest temperature of their utility for certain applications. Wax crystals of sufficient quantity can plug filters used in some fuel systems. 5.2 Petroleum blending operations require precise measurement of the cloud point. 5.3 This test method can determine the temperature of the test specimen at which wax crystals have formed sufficiently to be observed as a cloud with a resolution of 0.1 °C. 5.4 This test method provides results that, when rounded to the next lower integer, are equivalent to Test Method D2500 . Refer to 12.2 . 5.5 This test method is more precise than Test Method D2500 . Note 1: According to interlaboratory examination, the reproducibility of this test method has been found to be more precise than Test Method D2500 .