1.1 本试验方法包括通过手动测量单纤维长度来测定人造纤维和天然纤维的平均短纤维长度和短纤维长度分布。该测试方法也用于测量从短纤维纱线上取下的纤维长度，但这种测量可能不代表制造的纤维的短纤维长度。 1.2 由于该测试方法只需要测量50根纤维的长度，因此不适合用于确定样品中不常见的长纤维数量。 注1: 关于超长纤维的测定，请参阅测试方法 D3513 . 注2: 关于测定天然纤维平均长度和长度分布的方法，请参阅以下方法:对于棉花，请参阅测试方法 D1440 ，以及试验方法 D1447 ，羊毛，试验方法 D519 ，试验方法 D1234 ，以及试验方法 D1575 . 1.3 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。 1.4 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 本测试方法用于研究、开发、质量控制、产品规范，并可用于纺织纤维商业装运的验收测试。 然而，由于缺乏关于实验室间精度的信息，建议谨慎。按照中的指示进行比较测试 5.1.1 可能是可取的。 5.1.1 如果两个实验室（或更多实验室）的报告测试结果之间存在实际意义上的差异，则应进行比较测试，以确定它们之间是否存在统计偏差，并使用适当的统计协助。至少，从获得不同测试结果的材料中提取尽可能同质的测试样本，并以相同数量随机分配给每个实验室进行测试。应使用更新数据的统计测试，在测试系列之前选择的概率水平上，比较两个实验室的测试结果。如果发现偏差，必须找到并纠正其原因，或者考虑到已知偏差，必须调整该材料的未来测试结果。 5.2 该测试方法为确定纤维样品中的平均纤维长度和长度分布提供了客观测量。 5.3 纤维样品的短纤维长度图可用于确定指定长度以上和以下的纤维相对数量。如果纤维太长，在纺纱过程中加工不好，如果短纤维占优势，纱线的断裂强度可能低于正常值。

1.1 This test method covers the determination of average staple length and staple length distribution of both manufactured and natural fibers by manually measuring single fiber lengths. This test method is also used to measure the length of fibers removed from a staple yarn, but such a measurement may not represent the fiber's staple length, as manufactured. 1.2 Because this test method requires measuring the length of only 50 fibers, it is not suitable for use in determining the number of long fibers that occur infrequently in a sample. Note 1: For determination for overlength fibers, refer to Test Method D3513 . Note 2: For methods covering the determination of the average length and length distribution of natural fibers, refer to the following methods: for cotton, Test Method D1440 , and Test Method D1447 , for wool, Test Method D519 , Test Method D1234 , and Test Method D1575 . 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 is used for research, development, quality control, product specifications, and may be used for acceptance testing of commercial shipments of textile fibers. However, caution is advised since information on between-laboratory precision is lacking. Comparative tests as directed in 5.1.1 may be advisable. 5.1.1 If there are differences of practical significance between reported test results for two laboratories (or more), comparative tests should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, test samples that are as homogenous as possible, drawn from the material from which the disparate test results were obtained, and randomly assigned in equal numbers to each laboratory for testing. The test results from the two laboratories should be compared using a statistical test for upaired data, at a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results for that material must be adjusted in consideration of the known bias. 5.2 This test method provides objective measurements for determining the average fiber length and length distribution in a sample of fiber. 5.3 The staple length diagram of a fiber sample can be used to determine the relative number of fibers above and below a specified length. If a fiber is too long, it will not process well in spinning, and if there is a preponderance of short fibers, the yarn might have lower than normal breaking strength.