1.1 本试验方法包括在100°F和210°F（37.78°C和98.89°C）下通过运动粘度测量估算石油的平均相对分子质量。 2. 它适用于平均相对分子质量在250至700范围内的样品，并适用于平均石油馏分。它不应该不加选择地应用于代表极端成分或具有异常窄的平均相对分子质量范围的油。 1.2 以英寸-磅单位表示的值应被视为标准值。括号中给出的值是对国际单位制的数学转换，仅供参考，不被视为标准值。 1.3 本标准并不旨在解决与其使用相关的所有安全问题（如果有的话）。本标准的使用者有责任在使用前建立适当的安全、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====== 5.1 该试验方法提供了一种通过另一种物理测量计算石油平均相对分子质量的方法。 5.2 平均相对分子质量是一个基本的物理常数，可以与其他物理性质结合使用来表征碳氢化合物混合物。

1.1 This test method covers the estimation of the mean relative molecular mass of petroleum oils from kinematic viscosity measurements at 100 °F and 210 °F (37.78 °C and 98.89 °C). 2 It is applicable to samples with mean relative molecular masses in the range from 250 to 700 and is intended for use with average petroleum fractions. It should not be applied indiscriminately to oils that represent extremes of composition or possess an exceptionally narrow mean relative molecular mass range. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that 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 ====== 5.1 This test method provides a means of calculating the mean relative molecular mass of petroleum oils from another physical measurement. 5.2 Mean relative molecular mass is a fundamental physical constant that can be used in conjunction with other physical properties to characterize hydrocarbon mixtures.