1.1 本试验方法涵盖了一个确定垫圈材料对吸湿膨胀和收缩引起的线性尺寸变化的稳定性的程序。它将样品置于极端条件下，即烘箱干燥和完全浸入水中，这与低相对湿度和高相对湿度具有良好的相关性。 2. 1.2 以国际单位制表示的数值应视为标准。括号中给出的值仅供参考。 1.3 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。 1.4 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====== 3.1 垫片材料从制造点到安装在法兰中都要经过几个加工步骤。许多应用需要对尺寸变化进行严格控制。出于设计和质量保证的目的，需要一种准确的测试方法来确定各种材料的相对稳定性。这种测试方法在这方面是有用的。它模拟了材料在安装前可能经历的极端储存条件。允许样品不受限制地膨胀或收缩，因此该测试方法不应用于预测夹在法兰或其他应用中或特定加工步骤中的行为。 3.2 该试验方法测量线性变化，如果试样不平坦、不均匀或没有空隙，则可能需要修改。

1.1 This test method covers a procedure to determine the stability of a gasket material to linear dimensional change due to hygroscopic expansion and contraction. It subjects a sample to extremes, that is, oven drying and complete immersion in water, that have shown good correlation to low and high relative humidities. 2 1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 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 ====== 3.1 Gasket materials undergo several processing steps from point of manufacture to installation in a flange. Many applications require close control of dimensional change. An accurate test method for determining the relative stability of various materials is needed for design and quality assurance purposes. This test method is useful towards that end. It simulates the extreme storage conditions that a material may undergo prior to installation. Samples are allowed unrestricted expansion or contraction, and so this test method should not be used to predict behavior clamped in a flange or other applications, or during specific processing steps. 3.2 This test method measures linear change, and may need to be modified if the test specimen is not flat, homogeneous, or free of voids.