1.1 本规程描述了使用渗透管动态校准仪器、分析仪和用于测量大气中气体或蒸汽浓度的分析程序的方法 ( 1. , 2. ) . 2. 1.2 可密封在渗透管中的典型材料包括:二氧化硫、二氧化氮、硫化氢、氯、氨、丙烷和丁烷 ( 1. ) . 1.3 以国际单位制表示的值应视为标准值。 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建立适当的安全、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《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 5.1 大多数用于空气污染物测量的分析方法本质上是比较性的，需要校准或标准化，或者两者都需要，通常需要已知的感兴趣气体混合物。由于许多重要的空气污染物都是反应性和不稳定的，因此很难将它们作为已知浓度的标准混合物进行储存，以便进行长期校准。另一种方法是根据需要动态制备标准混合物。如果可以提供恒定的感兴趣气体源，则简化了该过程。如果正确校准并保持在恒定温度下，渗透管提供该恒定源。环境保护局已将渗透管指定为某些分析程序的参考校准源 ( 3. ) .

1.1 This practice describes a means for using permeation tubes for dynamically calibrating instruments, analyzers, and analytical procedures used in measuring concentrations of gases or vapors in atmospheres ( 1 , 2 ) . 2 1.2 Typical materials that may be sealed in permeation tubes include: sulfur dioxide, nitrogen dioxide, hydrogen sulfide, chlorine, ammonia, propane, and butane ( 1 ) . 1.3 The values stated in SI units are to be regarded as 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 Most analytical methods used in air pollutant measurements are comparative in nature and require calibration or standardization, or both, often with known blends of the gas of interest. Since many of the important air pollutants are reactive and unstable, it is difficult to store them as standard mixtures of known concentration for extended calibration purposes. An alternative is to prepare dynamically standard blends as required. This procedure is simplified if a constant source of the gas of interest can be provided. Permeation tubes provide this constant source, if properly calibrated and if maintained at constant temperature. Permeation tubes have been specified as reference calibration sources, for certain analytical procedures, by the Environmental Protection Agency ( 3 ) .