1.1 本试验方法涵盖了测定高乙醇含量燃料氢离子活性测量值的程序。其中包括变性燃料乙醇和乙醇燃料混合物。本试验方法适用于变性燃料乙醇和含有51℃乙醇的乙醇燃料混合物 % 按体积或更大。 1.2 本试验方法中测得的氢离子活性定义为pHe。醇溶液的pHe值与水溶液的pH值不可比。 1.2.1 测得的pHe值在一定程度上取决于燃料混合物、搅拌速度和电极在燃料中的时间。 1.3 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。 1.3.1 水中的氢离子活性用pH表示，乙醇中的氢离子活性用pHe表示。 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、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《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 通过pHe测量的氢离子活性可以很好地预测乙醇燃料的腐蚀潜力。它优于总酸度，因为总酸度不能测量氢离子的活性； 高估弱酸（如碳酸）的贡献；并且可能低估低浓度强酸（如硫酸）的腐蚀潜力。

1.1 This test method covers a procedure to determine a measure of the hydrogen ion activity of high ethanol content fuels. These include denatured fuel ethanol and ethanol fuel blends. The test method is applicable to denatured fuel ethanol and ethanol fuel blends containing ethanol at 51 % by volume, or more. 1.2 Hydrogen ion activity as measured in this test method is defined as pHe. A pHe value for alcohol solutions is not comparable to pH values of water solutions. 1.2.1 The value of pHe measured will depend somewhat on the fuel blend, the stirring rate, and the time the electrode is in the fuel. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3.1 Hydrogen ion activity in water is expressed as pH and hydrogen ion activity in ethanol is expressed as pHe. 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 The hydrogen ion activity, as measured by pHe, is a good predictor of the corrosion potential of ethanol fuels. It is preferable to total acidity because total acidity does not measure activity of the hydrogen ions; overestimates the contribution of weak acids, such as carbonic acid; and can underestimate the corrosion potential of low concentrations of strong acids, such as sulfuric acid.