1.1 本试验方法包括使用干指示剂法测定水蒸气通过与液态水接触的薄膜所需的时间。 1.2 该方法已用于评估建筑施工中使用的防水屏障、柔性防水板和其他材料，以测量其对水蒸气传输的阻力。 1.3 以英寸-磅单位表示的数值视为标准值。括号中给出的值是数学转换为SI单位，仅供参考，不被视为标准单位。 1.4 本标准并不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（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 本试验方法中使用的干指示剂吸湿性很强，在中高湿度的环境中，它会变色，而不会接触液态水。当与液态水接触时，它也会发生变化。 5.2 本试验方法对于在一面与水接触的材料以及评估水蒸气通过材料的时间长度很重要的情况下具有价值。

1.1 This test method covers the determination of the time required for water vapor to pass through a sheet membrane in contact with liquid water using the dry-indicator method. 1.2 The method has been used to evaluate water resistive barriers, flexible flashing and other materials used in building construction in order to measure their resistance to water vapor transmission. 1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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 The dry indicator used in this test method is so strongly hygroscopic it will change color in a moderate- to high-humidity atmosphere without contacting liquid water. It will also change when in contact with liquid water. 5.2 This test method is of value for materials that come in contact with water on one face and where it is important to evaluate the length of time for water vapor to pass through the material.