1.1 一般来说，塑料的物理和电气性能受温度和相对湿度的影响，对测试结果产生重大影响。为了在不同材料之间和不同实验室之间进行可靠的比较，有必要在测试之前和测试期间对这些材料的样品的湿度条件以及温度进行标准化。本规程规定了试验前调节塑料的程序（尽管不一定要达到平衡）以及试验条件。 1.2 对于某些材料，可能存在需要使用本规程的材料规范，但需要进行一些程序修改。材料规范优先于本规程。使用本规程前，请参阅材料规范。桌子 分类中为1 D4000 列出了当前存在的ASTM材料规范。 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。 注1: 本标准和ISO 291涉及相同的主题，但技术内容不同。ISO 291仅描述了调节或测试或两者的两种温度和湿度条件。 1.4 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====== 4.1 试样的调节通常进行:( 1. )为了使材料与正常或平均房间条件保持平衡( 2. )只是为了获得可重复的结果，而不考虑之前的暴露历史，或( 3. )将材料置于异常温度或湿度条件下，以预测其使用行为。 4.2 本实施规程中规定的调节程序旨在获得可重复的结果，并有可能产生高于或低于正常条件下平衡值的物理值，具体取决于特定材料和试验。 根据材料的厚度、类型及其以前的历史，可能需要20到100天或更长时间才能确保在正常湿度和温度条件下的基本平衡。因此，再现性条件必须用于一般采购规范和产品控制测试。

1.1 In general, the physical and electrical properties of plastics are influenced by temperature and relative humidity in a manner that materially affects test results. In order to make reliable comparisons between different materials and between different laboratories, it is necessary to standardize the humidity conditions, as well as the temperature, to which specimens of these materials are subjected prior to and during testing. This practice defines procedures for conditioning plastics (although not necessarily to equilibrium) prior to testing, and the conditions under which they shall be tested. 1.2 For some materials, it is possible that a material specification exists that requires the use of this practice, but with some procedural modifications. The material specification takes precedence over this practice. Refer to the material specification before using this practice. Table 1 in Classification D4000 lists the ASTM material specifications that currently exist. 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. Note 1: This standard and ISO 291 address the same subject matter, but differ in technical content. ISO 291 describes only two temperature and humidity conditions for conditioning or testing, or both. 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 ====== 4.1 Conditioning of specimens is typically conducted: ( 1 ) for the purpose of bringing the material into equilibrium with normal or average room conditions, ( 2 ) simply to obtain reproducible results, regardless of previous history of exposure, or ( 3 ) to subject the material to abnormal conditions of temperature or humidity in order to predict its service behavior. 4.2 The conditioning procedures prescribed in this practice are designed to obtain reproducible results and have the potential to give physical values somewhat higher or somewhat lower than values under equilibrium at normal conditions, depending upon the particular material and test. Depending on the thickness, type of material and its previous history, it is possible that it would take 20 to 100 days or more to ensure substantial equilibrium under normal conditions of humidity and temperature. Consequently, conditioning for reproducibility must of necessity be used for general purchase specifications and product control tests.