1.1 本试验方法包括使用自动蒸气压仪器测定挥发性、液态石油产品、碳氢化合物和碳氢化合物含氧混合物（包括乙醇混合物）在真空中施加的蒸气压，最高可达85 % （体积分数）。本试验方法适用于测试沸点高于0的样品 摄氏度（32 °F）之间的蒸汽压 千帕和150 千帕（1.0 psi和21 psi）在37.8 摄氏度（100 °F），汽液比为4:1。分析所需的液体样品体积大小取决于所选的汽液比（参见 注1 )以及仪器的测量室容积（见 6.1.1 和 附注5 ). 注1: 本试验方法适用于测定挥发性液体石油产品在0 摄氏度至100度 汽液比为4:1至1:1（X=4:1）且压力高达500℃时 千帕（70 psi），但精度声明（见第节 16 )可能不适用。 注2: 精度（见第节 16 )在2003年实验室间研究（ILS）中确定使用1 L容器； 2. 精度使用250 mL容器在2016年ILS中确定。 3. 1.2 本试验方法还包括使用自动蒸汽压力仪表来确定航空涡轮燃料在真空中施加的蒸汽压力。 本试验方法适用于沸点高于0的航空涡轮燃料样品的试验 摄氏度（32 °F）之间的蒸汽压 千帕和110 千帕（0 psi和15.5 psi）的温度范围内以4:1的汽液比在25 摄氏度至100度 摄氏度（77 华氏度至212度 °F）。 注3: 精度（见第节 16 )2007年ILS中确定了使用100 mL容器的航空涡轮燃料。 4. 1.3 蒸汽压（VP 十、 )通过本试验方法在37.8下汽油和汽油含氧化合物混合物的汽液比为4:1（X=4）时测定 °C可与试验方法确定的干蒸汽压当量（DVPE）值相关 D5191 （见 16.3 ). 当样品为航空涡轮燃料时，该条件不适用。 1.4 以国际单位制表示的数值应视为标准值。SI单位后括号中给出的值仅供参考，不被视为标准值。 1.5 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的用户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。 有关特定警告声明，请参见 7.2 – 7.8 . 1.6 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 蒸汽压是用于运输和储存的挥发性液体的一个非常重要的物理性质。 5.2 汽油和汽油含氧混合物的蒸汽压由各种政府机构调节。 5.3 挥发性石油产品的规范通常包括蒸汽压力限制，以确保产品具有适当的挥发性性能。 5.4 在本试验方法中，测量前不需要空气饱和程序，因此消除了该步骤中高挥发性化合物的损失。该测试方法速度更快，并将不适当的空气饱和导致的潜在误差降至最低。 本试验方法允许VP 十、 现场测定。 5.5 该测试方法可应用于在线应用中，其中无法执行测量前的空气饱和程序。

1.1 This test method covers the use of automated vapor pressure instruments to determine the vapor pressure exerted in vacuum by volatile, liquid petroleum products, hydrocarbons, and hydrocarbon-oxygenate mixtures including ethanol blends up to 85 % (volume fraction). This test method is suitable for testing samples with boiling points above 0 °C (32 °F) that exert a vapor pressure between 7 kPa and 150 kPa (1.0 psi and 21 psi) at 37.8 °C (100 °F) at a vapor-to-liquid ratio of 4:1. The liquid sample volume size required for analysis is dependent upon the vapor-to-liquid ratio chosen (see Note 1 ) and the measuring chamber volume capacity of the instrument (see 6.1.1 and Note 5 ). Note 1: The test method is suitable for the determination of the vapor pressure of volatile, liquid petroleum products at temperatures from 0 °C to 100 °C at vapor to liquid ratios of 4:1 to 1:1 (X = 4 to 1) and pressures up to 500 kPa (70 psi), but the precision statement (see Section 16 ) may not be applicable. Note 2: The precision (see Section 16 ) using 1 L containers was determined in a 2003 interlaboratory study (ILS); 2 the precision using 250 mL containers was determined in a 2016 ILS. 3 1.2 This test method also covers the use of automated vapor pressure instruments to determine the vapor pressure exerted in vacuum by aviation turbine fuels. This test method is suitable for testing aviation turbine fuel samples with boiling points above 0 °C (32 °F) that exert a vapor pressure between 0 kPa and 110 kPa (0 psi and 15.5 psi) at a vapor-to-liquid ratio of 4:1, in the temperature range from 25 °C to 100 °C (77 °F to 212 °F). Note 3: The precision (see Section 16 ) for aviation turbine fuels using 100 mL containers was determined in a 2007 ILS. 4 1.3 The vapor pressure (VP X ) determined by this test method at a vapor-liquid ratio of 4:1 (X = 4) of gasoline and gasoline-oxygenate blends at 37.8 °C can be correlated to the dry vapor pressure equivalent (DVPE) value determined by Test Method D5191 (see 16.3 ). This condition does not apply when the sample is aviation turbine fuel. 1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard. 1.5 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 7.2 – 7.8 . 1.6 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 Vapor pressure is a very important physical property of volatile liquids for shipping and storage. 5.2 The vapor pressure of gasoline and gasoline-oxygenate blends is regulated by various government agencies. 5.3 Specifications for volatile petroleum products generally include vapor pressure limits to ensure products of suitable volatility performance. 5.4 In this test method, an air saturation procedure prior to the measurement is not required, thus eliminating losses of high volatile compounds during this step. This test method is faster and minimizes potential errors from improper air saturation. This test method permits VP X determinations in the field. 5.5 This test method can be applied in online applications in which an air saturation procedure prior to the measurement cannot be performed.