1.1 本试验方法涵盖了水蒸气通过柔性阻隔材料传输速率的动态评估，并允许转换为通过各种其他试验方法（包括试验方法中描述的重量法）获得的公认水蒸气传输单位（WVT） E96/E96M . 1.2 限制- 本试验方法仅限于由完全疏水性材料或疏水性和亲水性材料的组合组成的柔性阻隔板材料，其至少有一个表面为疏水性。 1.3 通过本试验方法获得的最小试验值受到通过试验仪器夹紧密封件的水蒸汽泄漏的限制。合理值可能约为0。 01克/24小时·米 2. 对于任何WVTR方法，包括测试方法的干燥剂程序 E96/E96M 37.8 °C和90 % 相对湿度。可以使用不透水样本（如铝箔）检查每个仪器的该极限。如果有规定，校准程序可以补偿泄漏率。 1.4 本试验方法不适用于此时的裁判试验，但适用于对照试验和材料比较。 1.5 其他几种ASTM测试方法可用于测试类似的性能。该试验方法的独特之处在于，它与典型的产品储存方法非常相似，在这种情况下，允许将包装中的水分转移到环境中，而无需不断用干燥气体清扫环境侧。持续清扫干燥面的方法包括试验方法 F1249 和 F3299 . 1.6 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。 1.7 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。 1.8 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 没有一组测试条件可以代表所有的气候和使用条件，因此，这种WVTR测试方法更适用于在规定的一组条件下比较不同的材料，而不是预测其在任何条件下的现场实际性能。 5.2 在已知和仔细控制的条件下，水蒸气透过率可用于评估板材的蒸汽阻挡质量。在不同试验温度和相对湿度条件下获得的值的直接相关性将是有效的，前提是试验中的阻隔材料在试验条件下或之间不会发生固态变化（例如结晶转变或熔点）。

1.1 This test method covers dynamic evaluation of the rate of transfer of water vapor through a flexible barrier material and allows conversion to the generally recognized units of water vapor transmission (WVT) as obtained by various other test methods including the gravimetric method described in Test Methods E96/E96M . 1.2 Limitations— This test method is limited to flexible barrier sheet materials composed of either completely hydrophobic materials, or combinations of hydrophobic and hydrophilic materials having at least one surface that is hydrophobic. 1.3 The minimum test value obtained by this test method is limited by the leakage of water vapor past the clamping seals of the test instrument. A reasonable value may be approximately 0.01 g/24 h·m 2 for any WVTR method including the desiccant procedure of Test Methods E96/E96M at 37.8 °C, and 90 % relative humidity. This limit can be checked for each instrument with an impervious specimen such as aluminum foil. Calibration procedures can compensate for the leakage rate if so stated. 1.4 This test method is not suitable for referee testing at this time, but is suitable for control testing and material comparison. 1.5 Several other ASTM test methods are available to test a similar property. This test method is unique in that it closely duplicates typical product storage where a transfer of moisture from a package into the environment is allowed to proceed without constantly sweeping the environmental side with dry gas. Methods with constantly swept dry sides include Test Methods F1249 and F3299 . 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.7 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. 1.8 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 No single set of test conditions can represent all climatic and use conditions, so this WVTR test method serves more to compare different materials at a stated set of conditions than to predict their actual performance in the field under any conditions. 5.2 The water vapor transmission rate, under known and carefully controlled conditions, may be used to evaluate the vapor barrier qualities of a sheet. Direct correlation of values obtained under different conditions of test temperature and relative humidity will be valid provided the barrier material under test does not undergo changes in solid state (such as a crystalline transition or melting point) at or between the conditions of test.