1.1 本试验方法描述了一种可在现场或实验室中使用的程序，用于量化液体燃料（包括与合成碳氢化合物或生物燃料混合的液体燃料）中作为污染物存在的可培养、可行的需氧微生物，其运动粘度为（40 °C） ≤ 24毫米 2. s -1 以及具有运动粘度（40 °C） ≤ 700毫米 2. s -1 和燃料相关水。 1.1.1 该测试方法已由ILS对一系列符合规范的中间馏分燃料进行了验证 D975 , D1655 ISO 8217 DMA和北约F-76。 2. 1.2 本试验方法定量评估了以细菌、真菌和真菌孢子形式存在的可培养、活性需氧微生物含量。结果表示为每升燃料的微生物菌落形成单位（CFU）总数或每毫升相关水的CFU总数。 CFU的数量不应解释为绝对值，而应作为诊断或状况监测工作的一部分；例如，这些值可用于评估无污染、轻度、中度或重度污染。 注1: 该试验方法在技术上等同于IP 613，尽管这两种方法目前尚未结合。 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 本试验方法旨在提供一种工具，用于评估燃料储存和分配设施或最终用户燃料箱是否会受到微生物生长的影响，并提醒燃料供应商或用户燃料质量或操作问题的可能性和/或预防或补救措施的要求。 5.2 该测试方法检测微生物菌落形成单位（CFU）的数量，与实验室标准程序实践中使用的检测参数相同 D6974 IP 385。然而，鉴于实践 D6974 IP 385提供了活需氧菌CFU和活真菌CFU数量的单独评估，该测试方法提供了活需氧菌和真菌CFU的组合总数。 5.3 本试验方法旨在检测与馏出燃料污染有关的一组公认的重要微生物，但公认的是，微生物培养技术不能检测样品中可能存在的所有微生物。 可培养性主要受捕获的微生物在特定生长条件下在提供的生长培养基上增殖的能力影响。因此，样本中存在的活性或非活性微生物种群的比例可以存活，但不能通过任何一种培养试验检测到。 7. 在这方面，试验表明了样品中微生物污染的程度，并且假设当燃料样品受到严重污染时，会定量检测到存在的一些主要微生物物种，即使并非所有存在的物种都是可培养的。 5.4 燃料系统中的许多样品可能含有低水平的“背景”微生物污染，这不一定具有操作意义。该测试方法的最低检测水平由测试样本的体积决定，并且设置为仅当微生物污染处于指示活跃增殖的水平时，才会检测到微生物污染。 5.5 该测试将检测具有代谢活性和休眠真菌孢子的可培养细菌和真菌。燃油样品中真菌孢子的存在可能表明燃油箱或系统内的微生物增殖活跃，但在远离取样位置的点。活跃的微生物生长只发生在自由水中，并且只能在水箱或系统低点以孤立的小袋形式出现。由于真菌孢子比活性细胞和真菌物质（菌丝）更具疏水性，它们更容易在燃料相中分散，因此当无法直接采样低点且样品中仅存在燃料相时，更容易检测到。 5.6 本试验方法可确定从燃油箱和系统中提取的样品中是否存在微生物污染，或是否存在轻度、中度和重度污染。 5.7 轻度、中度和重度污染的分类将取决于燃料类型、采样位置、采样设施及其具体操作环境。 5.8 有关测试结果的进一步指导或解释，请参阅指南 D6469 在《能源研究所石油燃料微生物含量调查指南》、《避免和补救策略实施指南》和《国际航空运输协会飞机燃油箱微生物污染指导材料》中。 5.8.1 在实践中可以找到关于取样的进一步指导 D7464 . 5.9 测试可以常规进行，也可以调查事件。 5.10 微生物测试不用于确定是否符合绝对燃料规范或限制。 对燃料中的微生物污染实施规范限制通常是不合适的，微生物污染水平不能单独或直接用于推断燃料质量或适用性。 5.11 在解释结果时，必须认识到，测试结果仅适用于所测试的特定样品和样本，而不一定适用于散装燃料。微生物污染通常在燃料系统中表现出高度不均匀的分布，因此，对单个样品的分析很少能提供对现有污染总体水平的完整评估。 5.12 水相通常比燃料相含有更多的微生物CFU，因此，需要对结果进行不同的解释。

1.1 This test method describes a procedure that can be used in the field or in a laboratory to quantify culturable, viable aerobic microorganisms present as contaminants in liquid fuels, including those blended with synthesized hydrocarbons or biofuels, with kinematic viscosities (at 40 °C) of ≤ 24 mm 2 s -1 and heavy and residual fuels with kinematic viscosities (at 40 °C) of ≤ 700 mm 2 s -1 and in fuel-associated water. 1.1.1 This test method has been validated by an ILS for a range of middle distillate fuels meeting Specifications D975 , D1655 , ISO 8217 DMA, and NATO F-76. 2 1.2 This test method quantitatively assesses culturable, viable aerobic microbial content present in the form of bacteria, fungi, and fungal spores. Results are expressed as the total number of microbial colony forming units (CFU)/L of fuel or total number of CFU/mL of associated water. The number of CFU should not be interpreted as absolute values but should be used as part of a diagnostic or condition monitoring effort; for example, these values can be used to assess contamination as absent, light, moderate, or heavy. Note 1: This test method is technically equivalent to IP 613, although the two methods are not currently jointed. 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 is intended to provide a tool for assessing whether fuel storage and distribution facilities or end user fuel tanks are subject to microbial growth and alert fuel suppliers or users to the potential for fuel quality or operational problems and/or the requirement for preventative or remedial measures. 5.2 This test method detects numbers of microbial colony forming units (CFU), the same detection parameter used in the laboratory standard procedures Practice D6974 and IP 385. However, whereas Practice D6974 and IP 385 provide separate assessment of numbers of viable aerobic bacteria CFU and numbers of viable fungal CFU, this test method provides a combined total count of viable aerobic bacteria and fungal CFU. 5.3 This test method is designed to detect a recognized group of microorganisms of significance in relation to contamination of distillate fuels, but it is recognized that microbiological culture techniques do not detect all microorganisms that can be present in a sample. Culturability is affected primarily by the ability of captured microbes to proliferate on the growth medium provided, under specific growth conditions. Consequently, a proportion of the active or inactive microbial population present in a sample can be viable but not detected by any one culture test. 7 In this respect, the test is indicative of the extent of microbial contamination in a sample,and it is assumed that when a fuel sample is significantly contaminated, some of the dominant microbial species present will be quantifiably detected, even if not all species present are culturable. 5.4 Many samples from fuel systems can be expected to contain a low level of “background” microbial contamination, which is not necessarily of operational significance. The minimum detection level of this test method is determined by the volume of specimen tested and is set such that microbial contamination will generally only be detected when it is at levels indicative of active proliferation. 5.5 The test will detect culturable bacteria and fungi that are metabolically active and dormant fungal spores. Presence of fungal spores in a fuel sample can be indicative of active microbial proliferation within a fuel tank or system, but at a point distant from the location sampled. Active microbial growth only occurs in free water, and this can be present only as isolated pockets at tank or system low points. Because fungal spores are more hydrophobic than active cells and fungal material (mycelium), they disperse more readily in fuel phase and are thus more readily detected when low points cannot be directly sampled and only fuel phase is present in samples. 5.6 This test method can determine whether microbial contamination in samples drawn from fuel tanks and systems is absent or present at light, moderate, and heavy levels. 5.7 The categorization of light, moderate, and heavy levels of contamination will depend on the fuel type, the sampling location, the facility sampled, and its specific operating circumstances. 5.8 Further guidance or interpretation of test results can be found in Guide D6469 , in the Energy Institute Guidelines for the investigation of the microbial content of petroleum fuels, and for the implementation of avoidance and remedial strategies and in the IATA Guidance Material on Microbiological Contamination in Aircraft Fuel Tanks. 5.8.1 Further guidance on sampling can be found in Practice D7464 . 5.9 Testing can be conducted on a routine basis or to investigate incidents. 5.10 Microbiological tests are not intended to be used to determine compliance with absolute fuel specifications or limits. The implementation of specification limits for microbiological contamination in fuels is generally not appropriate, and microbial contamination levels cannot be used alone or directly to make inferences about fuel quality or fitness for use. 5.11 When interpreting results, it must be appreciated that the test result applies only to the specific sample and specimen tested and not necessarily to the bulk fuel. Microbiological contamination usually shows a highly heterogeneous distribution in fuel systems, and therefore, analysis of a single sample will rarely provide a complete assessment of the overall levels of contamination present. 5.12 Water phase will usually contain substantially higher numbers of microbial CFU than fuel phase and, consequently, a different interpretation of results is required.