1.1 本指南涵盖了选择一种或多种适当的测试方法，以评估所有候选土工膜对各种渗透剂的特定应用的渗透性。在不同的使用条件下，土工膜作为不同气体、蒸汽和液体运输和迁移的屏障的用途差异很大，需要通过与使用相关并模拟使用的测试方法来确定渗透率。土工膜是一种无孔、均匀的材料，通过以下三步过程，在分子尺度上对气体、蒸汽和液体具有不同程度的渗透性:( 1. )在上游侧的土工膜中溶解或被土工膜吸收( 2. )通过土工膜的扩散，以及( 3. )在屏障的下游侧解吸。 1.2 给定化学物质的传输速率，无论是作为单一渗透剂还是混合物，都是由其化学势驱动的，或者实际上是由其在土工膜上的浓度梯度驱动的。参考并简要描述了评估土工膜对单组分渗透剂（如单个气体、蒸汽和液体）渗透性的各种方法。 1.3 讨论了测量复杂混合物（如废液）中单个物种通过土工膜的渗透和透射的各种测试方法。 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）。 本标准的使用者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》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 土工膜的主要特征是其对各种气体、蒸汽和液体的固有低渗透性，两者都是单一的- 组分流体和多种组分的复杂混合物。作为低渗透材料，土工膜在岩土工程、环境和交通领域的广泛工程应用中被用作控制流动流体及其成分迁移的屏障。潜在渗透剂的范围很广，使用条件可能有很大差异。本指南向用户展示了可用于确定土工膜对各种渗透剂的渗透性的测试方法。 5.2 各种物种通过土工膜的传播受到许多因素的影响，必须对这些因素进行评估，才能预测其对特定服务的有效性。 渗透率测量受到测试条件的影响，并且通过一种方法进行的测量不能从一种应用转换到另一种应用。已经设计了各种各样的渗透性测试来测量聚合物材料的渗透性；然而，只有有限数量的这些程序被应用于土工膜。测试条件和程序的选择应尽可能反映实际的服务要求。需要注意的是，现场条件可能很难在实验室中建模或维护。这可能会影响土工膜样品的表观性能。 5.3 本指南讨论了可移动化学物质通过土工膜渗透的机理，以及与各种应用和渗透物质相关的渗透性测试。 描述并讨论了土工膜对含有各种渗透剂的单组分流体和多组分流体的渗透性的具体测试。

1.1 This guide covers selecting one or more appropriate test methods to assess the permeability of all candidate geomembranes for a proposed specific application to various permeants. The widely different uses of geomembranes as barriers to the transport and migration of different gases, vapors, and liquids under different service conditions require determinations of permeability by test methods that relate to and simulate the service. Geomembranes are nonporous, homogeneous materials that are permeable in varying degrees to gases, vapors, and liquids on a molecular scale in a three-step process by: ( 1 ) dissolution in or absorption by the geomembrane on the upstream side, ( 2 ) diffusion through the geomembrane, and ( 3 ) desorption on the downstream side of the barrier. 1.2 The rate of transmission of a given chemical species, whether as a single permeant or in mixtures, is driven by its chemical potential or in practical terms by its concentration gradient across the geomembrane. Various methods to assess the permeability of geomembranes to single component permeants, such as individual gases, vapors, and liquids are referenced and briefly described. 1.3 Various test methods for the measurement of permeation and transmission through geomembranes of individual species in complex mixtures such as waste liquids are discussed. 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 The principal characteristic of geomembranes is their intrinsically low permeability to a broad range of gases, vapors, and liquids, both as single-component fluids and as complex mixtures of many constituents. As low-permeable materials, geomembranes are being used in a wide range of engineering applications in geotechnical, environmental, and transportation areas as barriers to control the migration of mobile fluids and their constituents. The range of potential permeants is broad and the service conditions can differ greatly. This guide shows users test methods available for determining the permeability of geomembranes to various permeants. 5.2 The transmission of various species through a geomembrane is subject to many factors that must be assessed in order to be able to predict its effectiveness for a specific service. Permeability measurements are affected by test conditions, and measurements made by one method cannot be translated from one application to another. A wide variety of permeability tests have been devised to measure the permeability of polymeric materials; however, only a limited number of these procedures have been applied to geomembranes. Test conditions and procedures should be selected to reflect actual service requirements as closely as possible. It should be noted that field conditions may be difficult to model or maintain in the laboratory. This may impact apparent performance of geomembrane samples. 5.3 This guide discusses the mechanism of permeation of mobile chemical species through geomembranes and the permeability tests that are relevant to various types of applications and permeating species. Specific tests for the permeability of geomembranes to both single-component fluids and multicomponent fluids that contain a variety of permeants are described and discussed.