1.1 本规程提供了一种程序，用于比较使用不同类型的自动粒子计数器（在不同测量原理下运行）测定的试样中非球形粒子的大小。 1.2 通过比例因子，在检查给定粉末时，可以将一种仪器的尺寸比例尺乘以另一种仪器的尺寸比例尺。 1.3 本规程考虑了过滤研究中使用的无纤维刚性颗粒，例如:商用石英或氧化铝测试标准，或粉煤灰，或一些粉末化学试剂，如氧化铁或硫酸钙。 1.4 考虑了三种自动粒子计数器: 1.4.1 图像分析仪，在显微镜下观察静止颗粒，在本实践中，测量单个颗粒的最长端到端距离。 1.4.2 光学计数器，测量粒子经过窗口时投射的阴影面积； 和 1.4.3 电阻计数器，用于测量粒子通过导电液体中孔口时的体积。 1.5 本规程还考虑了提供沉降分析的仪器的使用，即提供作为斯托克斯直径函数的颗粒质量分布的测量。该实践提供了一种将质量分布转换为数量分布的方法，以便斯托克斯直径的意义可以与仪器测量的直径相关 1.4 . 1.6 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。 1.7 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。 1.8 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====== 4.1 本规程支持旨在评估流体过滤介质性能的测试方法，例如，规程 F796 其中讨论了粒度分布，同时，本规程提供了一种方法来比较从几种不同类型仪器获得的粒度测量值。 4.2 将一种直径标度转换为另一种直径标度的系数仅适用于所研究的特定测试颗粒。

1.1 This practice provides a procedure for comparing the sizes of nonspherical particles in a test sample determined with different types of automatic particle counters, which operate on different measuring principles. 1.2 A scale factor is obtained by which, in the examination of a given powder, the size scale of one instrument may be multiplied to agree with the size scale of another. 1.3 The practice considers rigid particles, free of fibers, of the kind used in studies of filtration, such as: commercially available test standards of quartz or alumina, or fly ash, or some powdered chemical reagent, such as iron oxide or calcium sulfate. 1.4 Three kinds of automatic particle counters are considered: 1.4.1 Image analyzers, which view stationary particles under the microscope and, in this practice, measure the longest end-to-end distance of an individual particle. 1.4.2 Optical counters, which measure the area of a shadow cast by a particle as it passes by a window; and 1.4.3 Electrical resistance counters, which measure the volume of a particle as it passes through an orifice in an electrically conductive liquid. 1.5 This practice also considers the use of instruments that provide sedimentation analyses, which is to say provide measures of the particle mass distribution as a function of Stokes diameter. The practice provides a way to convert mass distribution into number distribution so that the meaning of Stokes diameter can be related to the diameter measured by the instruments in 1.4 . 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.7 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. 1.8 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 supports test methods designed to evaluate the performance of fluid-filter media, for example, Practice F796 wherein particle size distributions are addressed and at the same time this practice provides a means to compare size measurements obtained from several different types of instruments. 4.2 The factor for converting one kind of diameter scale to another is only valid for the specific test particles studied.