1.1 这些测试方法涵盖材料的水蒸气透过率(WVTR)的测定，例如但不限于纸、塑料薄膜、其他片材、涂料、泡沫、纤维板、石膏和石膏制品、木制品和塑料。为WVTR的测量提供了两种基本方法，干燥剂法和水法。在这些测试中，使用期望的温度和左右湿度条件，由此产生的蒸汽驱动通过样品。所采用的测试条件由用户自行决定，但在所有情况下，都与结果一起报告。 1.2 以英寸-磅或SI单位表示的值应单独视为标准值。每个系统中陈述的值不一定完全等同；因此，每个系统应独立使用。使用适当的转换因子将导出的结果从一个系统转换到另一个系统（参见 表1 ). 1.3 本标准并不旨在解决与其使用相关的所有安全性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 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 这些测试的目的是通过简单的重量测定程序确定材料的水蒸气透过率。5.2 测试条件: 5.2.1 在一组测试条件下以一种方法获得的WVTR结果不能用于预测在不同条件下使用相同方法或使用其他方法获得的结果。见 附录X3 用于讨论确定WVTR对不同相对湿度（在给定温度下）的依赖性。 5.2.2 在各种工业或研究应用中通常使用或被认为是标准的测试条件在中被列为程序A-E 附录X1 但是这些条件的使用在本文的方法中不是强制性的。 5.2.3 鉴于 5.2.1 在可能的情况下，建议选择接近实际使用中材料暴露条件的测试条件。 5.2.4 当出于分类或符合性目的进行测试时，测试条件通常在规范、规范和制造商的技术文献中定义。

1.1 These test methods cover the determination of water vapor transmission rate (WVTR) of materials, such as, but not limited to, paper, plastic films, other sheet materials, coatings, foams, fiberboards, gypsum and plaster products, wood products, and plastics. Two basic methods, the Desiccant Method and the Water Method, are provided for the measurement of WVTR. In these tests, the desired temperature and side-to-side humidity conditions, with resultant vapor drive through the specimen, are used. The test conditions employed are at the discretion of the user, but in all cases, are reported with the results. 1.2 The values stated in either Inch-Pound or SI units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, each system shall be used independently of the other. Derived results are converted from one system to the other using appropriate conversion factors (see Table 1 ). 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 The purpose of these tests is to determine water vapor transmission rate of materials by means of a simple gravimetric procedure. 5.2 Test Conditions: 5.2.1 A WVTR result obtained in one method under one set of test conditions cannot be used to predict the result that would be obtained using the same method with a different set of conditions, or using the other method. See Appendix X3 for discussion of determining dependency of WVTR on different relative humidity (at a given temperature). 5.2.2 Test conditions that are commonly used or are considered standard in various industries or research applications are listed as Procedures A-E in Appendix X1 , but use of these conditions is not mandatory in the methods herein. 5.2.3 Given the caution in 5.2.1 , the selection of test conditions that closely approach exposure conditions of material in actual use is advised when possible. 5.2.4 Where tests are conducted for classification or compliance purposes, test conditions are typically defined in codes, specifications, and manufacturer’s technical literature.