1.1本试验方法描述了使用示踪气体稀释技术测量管道、烟囱、管道、矿井隧道或烟道内气流的体积和质量流率。为便于编辑，本文中的所有参考都将提及管道，但应理解，这同样适用于烟囱、管道、矿井隧道或烟道。本试验方法仅限于气流和示踪气体在测量条件下可被视为理想气体的应用。在本试验方法中，气流将被称为空气，尽管它可以是表现出理想气体定律行为的任何其他气体。 1.2本试验方法不限于任何特定的示踪气体，尽管实验经验表明，某些气体比其他气体更容易用作合适的示踪气体。示踪气体最好不是气流的天然成分。 1.3使用本试验方法需要了解气体分析和仪器的原理。正确使用此处给出的公式需要一致使用单位。 1.4 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和健康实践，并确定监管限制的适用性。 有关具体的预防说明，请参阅第7节。 ====意义和用途====== 本文提出的方法是一种现场方法，可用于确定流动条件可能不规则和不均匀的管道中的质量和体积流量。在管道中流动的气体被认为是理想气体。由于平均流速很低或测量位置上游和下游缺乏合适的管道，在传统皮托管或热风速计速度测量困难或不合适的位置，该方法可能特别有用。 该测试方法可以在标准条件下产生体积流量，而无需确定气流成分、温度和水蒸气含量。 该试验方法可用于确定HVAC管道、通风柜、通风立管和矿井隧道中的质量或体积流量，以及进行污染控制装置的模型研究。 该测试方法基于第一原理（质量守恒），不需要工程假设。 本试验方法不需要测量管道或烟囱的面积。 试验方法不需要流动矫直。 该测试方法与流动条件无关，例如角度、涡流、湍流、反转，因此不需要流动矫直。 干燥体积气流可以通过干燥空气样本而不测量水蒸汽浓度来确定。

1.1 This test method describes the measurement of the volumetric and mass flow rate of a gas stream within a duct, stack, pipe, mine tunnel, or flue using a tracer gas dilution technique. For editorial convenience all references in the text will be to a duct, but it should be understood that this could refer equally well to a stack, pipe, mine tunnel, or flue. This test method is limited to those applications where the gas stream and the tracer gas can be treated as ideal gases at the conditions of the measurement. In this test method, the gas stream will be referred as air, though it could be any another gas that exhibits ideal gas law behavior. 1.2 This test method is not restricted to any particular tracer gas although experimental experience has shown that certain gases are used more readily than others as suitable tracer gases. It is preferable that the tracer gas not be a natural component of the gas stream. 1.3 Use of this test method requires a knowledge of the principles of gas analysis and instrumentation. Correct use of the formulas presented here requires consistent use of units. 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 and health practices and to determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see Section 7. ====== Significance And Use ====== The method presented here is a field method that may be used to determine mass and volume flow rates in ducts where flow conditions may be irregular and nonuniform. The gas flowing in the duct is considered to be an ideal gas. The method may be especially useful in those locations where conventional pitot tube or thermal anemometer velocity measurements are difficult or inappropriate due either to very low average flow velocity or the lack of a suitable run of duct upstream and downstream of the measurement location. This test method can produce the volumetric flow rate at standard conditions without the need to determine gas stream composition, temperature, and water vapor content. This test method is useful for determining mass or volumetric flow rates in HVAC ducts, fume hoods, vent stacks, and mine tunnels, as well as in performing model studies of pollution control devices. This test method is based on first principles (conservation of mass) and does not require engineering assumptions. This test method does not require the measurement of the area of the duct or stack. The test method does not require flow straightening. The test method is independent of flow conditions, such as angle, swirl, turbulence, reversals, and hence, does not require flow straightening. The dry volumetric airflow can be determined by drying the air samples without measuring the water vapor concentration.