1.1 本规程旨在协助选择、制备、暴露和分析见证表面，以表征洁净室和相关受控环境中的颗粒沉积速率，尤其是航空航天应用。 1.2 可以根据粒度分布和计数、面积覆盖率或产品性能标准（如光传输或散射）来定义要求。提供了见证表面的几种选择。 1.3 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。 1.4 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。 1.5 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 本规程为测量洁净室和其他受控环境中的颗粒沉积或沉降物提供了标准方法。它基于使用见证表面收集周围环境中沉积的颗粒，然后通过常规方法对颗粒进行尺寸确定和计数。介绍了几种选项，以及为预期应用选择最佳选项的限制和指南。 5.2 这种做法适用于许多行业，包括航空航天、微电子和制药。

1.1 This practice is intended to assist in the selection, preparation, exposure, and analysis of witness surfaces for the purpose of characterizing particle deposition rates in cleanrooms and associated controlled environments, particularly for aerospace applications. 1.2 Requirements may be defined in terms of particle size distribution and count, percent area coverage, or product performance criteria such as optical transmission or scatter. Several choices for witness surfaces are provided. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 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. 1.5 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 practice provides a standard approach to measuring particle deposition, or fallout, in cleanrooms and other controlled environments. It is based on the use of a witness surface to collect particles that deposit from the surrounding environment and subsequently sizing and counting the particles by conventional methods. Several options are introduced, with limitations and guidelines for selecting the best choice for the intended application. 5.2 This practice is applicable across numerous industries including aerospace, microelectronics, and pharmaceuticals.