1.1 本试验方法包括通过计算指定距离内孔壁交点的数量来测定硬质泡沫塑料的表观孔尺寸。 1.2 程序A需要制备薄切片，其厚度不超过平均细胞直径的一半，且具有机械稳定性。对于大多数硬质泡沫塑料，这将试验方法限制为平均孔径至少为0.2 mm的材料。 1.3 程序B适用于易碎性使其难以获得薄片进行观察的材料。 1.4 以国际单位制表示的数值应视为标准值。 括号中给出的值仅供参考。 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。 注1: ISO 2896附录在技术上等同于本试验方法。 1.6 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 硬质泡沫塑料的几种物理性能取决于泡孔尺寸和泡孔方向。根据试验方法测量吸水率和开孔含量 D2842 和试验方法 D6226 需要了解表面单元体积，该体积在计算中使用单元尺寸值。 5.2 该测试方法提供了一个明显的单元大小，因为它假设平均单元大小中没有可测量的边到边或从上到下的变化，并且关于平均单元大小的单元大小分布是正常的。如果分析员担心平均单元大小或单元大小分布可能存在显著变化，则可能需要更详细的分析。 5.3 在继续使用本试验方法之前，应参考被测材料的规范。材料规范中涵盖的任何试样制备、调节、尺寸或测试参数，或其组合，应优先于本试验方法中提及的。如果没有材料规范，则默认条件适用。 图1 刀片式细胞大小样本切片器 图2 单元格大小的幻灯片组件

1.1 This test method covers the determination of the apparent cell size of rigid cellular plastics by counting the number of cell-wall intersections in a specified distance. 1.2 Procedure A requires the preparation of a thin slice, not more than one half the average cell diameter in thickness, that is mechanically stable. For most rigid cellular plastics this limits the test method to materials with an average cell size of at least 0.2 mm. 1.3 Procedure B is intended for use with materials whose friable nature makes it difficult to obtain a thin slice for viewing. 1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only. 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. Note 1: The annex to ISO 2896 is technically equivalent to this test method. 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 ====== 5.1 Several physical properties of rigid cellular plastics are dependent on cell size and cell orientation. Measuring water absorption and open-cell content in accordance with Test Method D2842 and Test Method D6226 requires knowledge of surface cell volume, which uses cell size values in the calculations. 5.2 This test method provides an apparent cell size because it assumes that there is no measurable edge to edge or top to bottom variation in average cell size and that the cell size distribution about the average cell size is normal. If the analyst is concerned there may be significant variation in either the average cell size or the cell size distribution more detailed analysis may be required. 5.3 Before proceeding with this test method, reference should be made to the specification of the material being tested. Any test specimen preparation, conditioning, dimensions, or testing parameters, or a combination thereof, covered in the materials specification shall take precedence over those mentioned in this test method. If there are no material specifications, then the default conditions apply. FIG. 1 Razor Blade Cell Size Specimen Slicer FIG. 2 Cell Size Scale Slide Assembly