1.1 本试验方法涵盖了现场和实验室使用的快速便携式方法，用于评估柴油燃料（纯柴油和含添加剂的柴油）通过玻璃纤维凝聚材料时释放夹带或乳化水的能力。 1.2 本试验方法适用于柴油，如规范 D975 所有硫水平的1-D级和2-D级，规范 D7467 生物柴油混合物B6-B20和MIL-DTL-16884，海军馏分燃料（北约F-76）。 注1: 本试验方法与试验方法相似 D3948 其适用于航空涡轮燃料。 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。 1.4 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。 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 本试验方法提供了柴油燃料中表面活性剂存在的测量方法，可在现场或实验室进行。相似试验方法 D3948 用于喷气燃料，该测试方法可以检测燃料中残留的一些炼油厂处理化学品的痕迹。 它还可以检测在从生产点到使用点的处理过程中添加到燃料中或由燃料拾取的表面活性物质。 5.2 某些添加剂可作为弱表面活性剂，其DSEP等级略有降低。其他强表面活性剂物质的DSEP等级要低得多。 5.3 本试验方法建议在测试含有少于1 % 生物柴油含量。测试B1-B20共混物时，应使用DB电池聚结器。弱表面活性剂的DSEP额定值略有降低，不会显著影响过滤器分离器从燃料中分离游离水的能力。强表面活性剂的DSEP等级低得多，并对过滤器分离器从燃料中分离游离水的能力产生不利影响。 5.4 该试验方法的结果与水箱中的水沉降速率没有已知关系。 5.5 微分离计仪器的测量范围为50至100。超出这些限值的值未定义且无效。 注2: 在获得大于100的值的情况下，光透射率很可能因用于设置100参考水平的燃料中包含的材料而降低。随后在试验的聚结部分移除材料，因此，处理过的燃料具有比用于获得100参考水平的燃料样品更高的透光率，导致最终额定测量值超过100。

1.1 This test method covers a rapid portable means for field and laboratory use to rate the ability of diesel fuels (both neat and those containing additives) to release entrained or emulsified water when passed through fiberglass coalescing material. 1.2 This test method is applicable to diesel fuels such as Specification D975 Grade No. 1-D and Grade No. 2-D of all sulfur levels, Specification D7467 biodiesel blends B6-B20, and MIL-DTL-16884, naval distillate fuel (NATO F-76). Note 1: This test method is similar to Test Method D3948 which is applicable to aviation turbine fuels. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.4 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 This test method provides a measure of the presence of surfactants in diesel fuels, and can be performed in the field or in a laboratory. Like Test Method D3948 used for jet fuel, this test method can detect traces of some refinery treating chemicals left in fuel. It can also detect surface active substances added to or picked up by the fuel during handling from point of production to point of use. 5.2 Certain additives, which can act as weak surfactants, give a slightly reduced DSEP rating. Other substances which are strong surfactants give much lower DSEP ratings. 5.3 This test method recommends use of the D cell coalescer when testing ULSD that contains less than 1 % biodiesel content. The DB cell coalescer should be used when testing B1-B20 blends. Weak surfactants, with slightly reduced DSEP ratings, do not significantly affect the ability of filter separators to separate free water from the fuel. Strong surfactants give a much lower DSEP rating and adversely affect the ability of filter separators to separate free water from the fuel. 5.4 Results from this test method do not have a known relationship to the rate of water settling in tanks. 5.5 The Micro-Separometer instrument has a measurement range from 50 to 100. Values obtained outside of those limits are undefined and invalid. Note 2: In the event a value greater than 100 is obtained, there is a good probability that light transmittance was reduced by material contained in the fuel used to set the 100 reference level. The material was subsequently removed during the coalescing portion of the test, thus, the processed fuel had a higher light transmittance than the fuel sample used to obtain the 100 reference level resulting in the final rating measuring in excess of 100.