1.1 本试验方法涵盖了测定植物（绿色）屋顶系统排水层中使用的粗颗粒材料的透水性的程序。 1.2 本试验方法解决了低水头条件下的透水性问题，该条件代表了植被（绿色）屋顶应用中的水平流。 1.3 本试验方法适用于具有100 % 保留在美国的材料。 #8 [2.25 mm]筛。它不适用于细粒度材料。 1.4 以国际单位制或英寸-磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 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）。本标准的用户有责任制定适当的安全、健康和环境实践，并在使用前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（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 本试验方法阐述了植被（绿色）屋顶系统在排水介质透水性方面的性能特征。 5.1.1 粗粒材料的透水性在很大程度上受测量水头条件的影响。在植被（绿色）屋顶中，粗材料经常用于为渗滤雨水创建排水区。 5.1.2 本试验方法旨在提供与该设计条件相关的透水性数据，该设计条件以低水头下的水平流为特征。这还可以将植物（绿色）屋顶系统中颗粒排水层的性能直接与替代组件进行比较，例如土工合成排水层。 5.2 确定植被（绿色）屋顶系统的性能特征可提供信息，以便于评估设施的相关工程方面。这些方面可能包括结构设计要求、机械工程和热设计要求以及消防和生命安全要求。 5.3 确定植被（绿色）屋顶系统的性能特征可提供信息，以便于评估一个植被（绿色）屋顶系统相对于另一个植被（绿色）屋顶系统的性能。

1.1 This test method covers a procedure for determining the water permeability of coarse granular materials used in the drainage layers of vegetative (green) roof systems. 1.2 This test method addresses water permeability under the low-head conditions that typify horizontal flow in vegetative (green) roof applications. 1.3 This test method is suitable for coarse-grained materials with 100 % of the material retained on the U.S. #8 [2.25 mm] sieve. It is not suitable for finer-grained materials. 1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the 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 to 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 ====== 5.1 This test method addresses performance characteristics for vegetative (green) roof systems with respect to the water permeability of the drainage media. 5.1.1 Water permeability of coarse materials is highly influenced by the head conditions under which it is measured. In vegetative (green) roofs, coarse materials are frequently used to create drainage zones for percolated rainfall. 5.1.2 This test method is intended to provide water permeability data that is relevant to this design condition that is characterized by horizontal flow under low-head. This will also allow the performance of granular drainage layers in vegetative (green) roof systems to be compared directly to alternative components, such as geocomposite drain layers. 5.2 Determining the performance characteristics of vegetative (green) roof systems provides information to facilitate the assessment of related engineering aspects of the facility. Such aspects may include structural design requirements, mechanical engineering and thermal design requirements, and fire and life safety requirements. 5.3 Determining the performance characteristics of vegetative (green) roof systems provides information to facilitate assessment of the performance of one vegetative (green) roof system relative to another.