1.1 本标准涵盖了煤的等级分类，即根据其在从褐煤到无烟煤的自然系列中的变质程度或渐进蚀变程度。 1.2 该分类适用于主要由镜质组组成的煤。 注1: 富含惰质组分或脂质组分（exinite）或两者的煤无法正确分类，因为在这些显微组分中，决定等级的性质（热值、挥发性物质和团聚特征）与同一煤中的镜质组的性质有很大不同。通常，这种煤可以通过宏观检查来识别。 在北美，这些煤大多是未结合的品种，只含有一小部分玻璃质，主要由消耗性材料组成。非粘结煤和其他贫镜质组煤的变质程度可以通过确定分离或浓缩镜质组分的分类特性或通过确定镜质组的反射率来估计（见试验方法 798英镑 和 附录X1 该分类的）。然而，在使用这些贫镜质组的煤时，一些通常与煤阶相关的性质，如流变性、燃烧性、硬度和可磨性（以及决定煤阶的性质）可能与镜质组有很大不同- 变质程度相同的富煤。 1.3 大量矿物质对挥发性物质和热值的测定以及对无矿物质基础的计算的影响可能会损害不纯煤分类的准确性。 1.4 以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 1.4.1 例外情况- 以英国热量单位每磅（Btu/lb）表示的数值应视为标准。Btu/lb的国际单位制当量仅供参考，不被视为标准。 1.5 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。 1.6 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 这种分类根据分级特性确定了煤的类别，分级特性主要取决于煤在埋藏时所受的变质程度。这些类别表明了一系列的物理和化学特征，这些特征有助于对煤炭在开采、制备和使用中的行为进行广泛的估计。

1.1 This standard covers the classification of coals by rank, that is, according to their degree of metamorphism, or progressive alteration, in the natural series from lignite to anthracite. 1.2 This classification is applicable to coals that are composed mainly of vitrinite. Note 1: Coals rich in inertinite or liptinite (exinite), or both, cannot be properly classified because, in those macerals, the properties that determine rank (calorific value, volatile matter, and agglomerating character) differ greatly from those of vitrinite in the same coal. Often, such coals can be recognized by megascopic examination. In North America, these coals are mostly nonbanded varieties that contain only a small proportion of vitrain and consist mainly of attrital materials. The degree of metamorphism of nonbanded and other vitrinite-poor coals can be estimated by determining the classification properties of isolated or concentrated vitrinite fractions, or by determining the reflectance of the vitrinite (see Test Method D2798 and Appendix X1 of this classification). However, in the use of these vitrinite-poor coals, some properties normally associated with rank, such as rheology, combustibility, hardness, and grindability (as well as the rank determining properties) may differ substantially from those of vitrinite-rich coals of the same degree of metamorphism. 1.3 The accuracy of the classification of impure coal may be impaired by the effect of large amounts of mineral matter on the determination of volatile matter and calorific value, and on their calculation to the mineral-matter-free basis. 1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 1.4.1 Exception— The values stated in British thermal units per pound (Btu/lb) are to be regarded as the standard. The SI equivalents of Btu/lb are provided for information only and are not considered standard. 1.5 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. 1.6 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 classification establishes categories of coal based on gradational properties that depend principally on the degree of metamorphism to which the coal was subjected while buried. These categories indicate ranges of physical and chemical characteristics that are useful in making broad estimates of the behavior of coal in mining, preparation, and use.