1.1 本试验方法涵盖了可在现场或实验室中用于定量液体燃料（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的、有活力的需氧微生物的程序，其运动粘度（40°C）为 ≤ 24毫米 2 s -1 以及运动粘度（40°C时）为 ≤ 700毫米 2 s -1 以及与燃料相关的水中。 1.1.1 该试验方法已通过ILS对一系列符合质量标准的中间馏分油进行了验证 D975 , D1655 、ISO 8217 DMA和北约F-76。 2 1.2 该测试方法定量评估以细菌、真菌和真菌孢子形式存在的可培养的、活的需氧微生物含量。结果表示为微生物菌落形成单位(CFU)/升燃料的总数或相关水的CFU/毫升总数。CFU的数量不应被解释为绝对值，而应被用作诊断或状况监测工作的一部分；例如，这些值可用于将污染评估为不存在、轻度、中度或重度。 附注1: 该测试方法在技术上与IP 613一致，尽管这两种方法目前尚未结合。 1.3 以SI单位表示的值将被视为标准值。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性问题（如果有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践并确定法规限制的适用性。 1.5 本国际标准是根据《关于制定国际标准的原则的决定》中确立的国际公认的标准化原则制定的世界贸易组织技术性贸易壁垒（TBT）委员会发布的des和建议。 ======意义和用途====== 5.1 该测试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受到微生物生长的影响，并提醒燃料供应商或用户注意潜在的燃料质量或操作问题和/或预防或补救措施的要求。 5.2 该检测方法检测微生物菌落形成单位（CFU）的数量，与实验室标准规程实践中使用的检测参数相同 D6974 和IP 385。然而，鉴于实践 D6974 和IP 385提供了活需氧细菌CFU的数量和活真菌CFU的数量的单独评估，该测试方法提供了活需氧细菌和真菌CFU的组合总数。5.3 该测试方法被设计为检测与馏分燃料污染相关的公认的重要微生物组，但认识到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所提供的生长培养基上增殖的能力的影响。因此，样品中存在的活性或非活性微生物群体的比例可以是活的，但不能通过任何一种培养测试检测到。 7 在这方面，测试指示样品中微生物污染的程度，并且假设当燃料样品被显著污染时，存在的一些优势微生物物种将被定量检测，即使不是所有存在的物种都是可培养的。5.4 来自燃料系统的许多样品可以预期含有低水平的“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确定，并且设置为使得微生物污染通常仅在指示活跃增殖的水平时检测到。 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。燃料样品中真菌孢子的存在可以指示燃料箱或系统内的活性微生物增殖，但在远离采样位置的点处。活跃的微生物生长仅发生在自由水中，并且这只能作为水箱或系统低点的孤立口袋存在。因为真菌孢子比活性细胞和真菌材料（菌丝体）更疏水，所以它们更容易分散在燃料相中，因此当不能直接取样低点并且样品中仅存在燃料相时更容易检测到。 5.6 该测试方法可以确定从燃料箱和系统抽取的样品中是否不存在或存在轻度、中度和重度微生物污染。 5.7 轻度、中度和重度污染水平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，请参见指南 D6469 能源研究所《石油燃料微生物含量调查指南》、《避免和补救战略实施指南》和《国际航空运输协会关于飞机燃料箱微生物污染的指导材料》。5.8.1 关于抽样的进一步指导可以在实践中找到 D7464 . 5.9 测试可以常规进行，也可以调查事故。 5.10 微生物测试不用于确定是否符合绝对燃料规格或限值。燃料中微生物污染的规格限值的实施通常是不合适的，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，必须理解，测试结果仅适用于被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，单个样品的分析很少能提供对存在的总体污染水平的完整评估。5.12 水相通常含有比燃料相高得多的微生物CFU，因此，需要对结果进行不同的解释。

1.1 This test method covers 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 harmonized with 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.