1.1 本试验方法描述了在40°C下测定粘度小于24 cSt的所用电绝缘液体的近似总酸值。这是一个可以在现场应用的简单程序。如果需要定量中和值，则使用测试方法 D664页 或试验方法 D974 . 这些试验方法应在实验室中应用。 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和健康实践，并确定监管限制的适用性。 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====== 4.1 使用过的电气绝缘油的近似酸度是对油的总酸值的估计。随着酸值增加，油质降低。这通常是由于机油在使用过程中氧化所致。一般来说，酸性副产物会增加介电损耗，增加腐蚀性，并可能由于称为“污泥”的不溶性成分而导致热困难本试验方法适用于特定体积的油；每克油0.05至0.5 mg氢氧化钾的总酸值是一个具有重要功能的范围。

1.1 This test method describes the determination of the approximate total acid value of used electrical insulating liquids having viscosities less than 24 cSt at 40°C. It is a simple procedure that can be applied in the field. Where a quantitative neutralization value is required, use Test Method D664 or Test Method D974 . These test methods should be applied in the laboratory. 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 and health practices and determine the applicability of regulatory limitations prior to use. 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 ====== 4.1 The approximate acidity of used electrical insulating oils is an estimate of the total acid value of the oil. As acid values increase, oil quality decreases. This is usually due to oxidation of the oil while in service. In general, acidic by-products produce increased dielectric loss, increased corrosivity, and may cause thermal difficulties attributable to insoluble components called “sludge.” This test method is adapted to a specific volume of oil; total acid values of 0.05 to 0.5 mg of potassium hydroxide per gram of oil is a range which is functionally significant.