1.1 本试验方法涵盖了一种适用于测量硫化氢（H）总量的方法 2. S） 在重馏分油、重馏分油/残余燃料混合物或规范中定义的残余燃料中 D396页 等级4、5（轻）、5（重）和6，当H 2. 燃料中的硫浓度为0.01 μg/g（ppmw）至 100 μg/g（ppmw）范围。 1.2 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。 1.3 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。 有关特定警告声明，请参阅 7.5 , 8.2 , 9.2 , 10.1.4 和 11.1 . 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====== 5.1 残余燃油可能含有H 2. 这可能导致危险的气相H水平 2. 在储罐顶部空间中。气相水平可根据顶空体积、燃料温度和搅拌而显著变化。H的测量 2. 液相中的S水平提供了一个有用的指示，表明残余燃料油形成高汽相水平的倾向，而残余燃料油中的较低水平将直接降低H的风险 2. S暴露。然而，至关重要的是，参与处理燃油的任何人，如船舶所有人和操作员，应继续保持适当的安全做法，以保护船员、罐区操作员和其他可能接触H 2. S 5.1.1 H的测量 2. 液相S适合于产品质量控制，而H的测量 2. 出于健康和安全目的，气相中的S是合适的。 5.2 该测试方法的开发是为了使炼油厂、燃料终端操作员和独立测试实验室人员能够分析测量氢的含量 2. 残余燃油液相中的S。 注1: 试验方法 D6021 是定量测量H的三种测试方法之一 2. 残余燃料中的硫: 1） 试验方法 D5705 是一种测定H的简单现场试验方法 2. 蒸汽相中的S能级。 2） 试验方法 D7621 是一种快速测定H的测试方法 2. S液相液位。 5.3 H 2. 在静态系统中，液相和汽相中的硫浓度试图达到平衡。然而，这种平衡以及相关的液体和蒸汽浓度可能会因温度和液相的化学成分而发生很大变化。H的浓度为1 mg/kg（μg/g）（ppmw） 2. 残余燃料液相中的S通常会产生大于50的实际气体浓度 μL/L（ppmv）至100μL/L（ppmv）的H 2. 但是，当打开通风口或接入点收集样品时，气相的平衡被破坏。 注2: 由于H的反应性、吸收率和挥发性 2. S任何测量方法仅提供H 2. S在给定时刻的浓度。

1.1 This test method covers a method suitable for measuring the total amount of hydrogen sulfide (H 2 S) in heavy distillates, heavy distillate/residual fuel blends, or residual fuels as defined in Specification D396 Grade 4, 5 (Light), 5 (Heavy), and 6, when the H 2 S concentration in the fuel is in the 0.01 μg/g (ppmw) to 100 μg/g (ppmw) range. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 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. For specific warning statements, see 7.5 , 8.2 , 9.2 , 10.1.4 , and 11.1 . 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 ====== 5.1 Residual fuel oils can contain H 2 S in the liquid phase, and this can result in hazardous vapor phase levels of H 2 S in storage tank headspaces. The vapor phase levels can vary significantly according to the headspace volume, fuel temperature, and agitation. Measurement of H 2 S levels in the liquid phase provides a useful indication of the residual fuel oil’s propensity to form high vapor phase levels, and lower levels in the residual fuel oil will directly reduce risk of H 2 S exposure. It is critical, however, that anyone involved in handling fuel oil, such as vessel owners and operators, continue to maintain appropriate safety practices designed to protect the crew, tank farm operators and others who can be exposed to H 2 S. 5.1.1 The measurement of H 2 S in the liquid phase is appropriate for product quality control, while the measurement of H 2 S in the vapor phase is appropriate for health and safety purposes. 5.2 This test method was developed so refiners, fuel terminal operators and independent testing laboratory personnel can analytically measure the amount of H 2 S in the liquid phase of residual fuel oils. Note 1: Test Method D6021 is one of three test methods for quantitatively measuring H 2 S in residual fuels: 1) Test Method D5705 is a simple field test method for determining H 2 S levels in the vapor phase. 2) Test Method D7621 is a rapid test method to determine H 2 S levels in the liquid phase. 5.3 H 2 S concentrations in the liquid and vapor phase attempt to reach equilibrium in a static system. However, this equilibrium and the related liquid and vapor concentrations can vary greatly depending on temperature and the chemical composition of the liquid phase. A concentration of 1 mg/kg (μg/g) (ppmw) of H 2 S in the liquid phase of a residual fuel can typically generate an actual gas concentration of >50 μL/L(ppmv) to 100 μL/L(ppmv) of H 2 S in the vapor phase, but the equilibrium of the vapor phase is disrupted the moment a vent or access point is opened to collect a sample. Note 2: Because of the reactivity, absorptivity, and volatility of H 2 S any measurement method only provides an H 2 S concentration at a given moment in time.