D02.14 - Stability, Cleanliness and Compatibility of Liquid Fuels

SIGNIFICANCE AND USE
5.1 This procedure describes a rapid and sensitive method for estimating the stability reserve of an oil. The stability reserve is estimated in terms of a separability number, where a low value of the separability number indicates that there is a stability reserve within the oil. When the separability number is between 0 to 5, the oil can be considered to have a high stability reserve and asphaltenes are not likely to flocculate. If the separability number is between 5 to 10, the stability reserve in the oil will be much lower. However, asphaltenes are, in this case, not likely to flocculate as long as the oil is not exposed to any worse conditions, such as storing, aging, and heating. If the separability number is above 10, the stability reserve of the oil is very low and asphaltenes will easily flocculate, or have already started to flocculate.  
5.2 This test method can be used by refiners and users of oils, for which this test method is applicable, to estimate the stability reserves of their oils. Hence, this test method can be used by refineries to control and optimize their refinery processes. Consumers of oils can use this test method to estimate the stability reserve of their oils before, during, and after storage.
FIG. 1 Schematic Representation of a Typical Measurement Using an Optical Scanning Device  
5.3 This test method is not intended for predicting whether oils are compatible before mixing, but can be used for determining the separability number of already blended oils. However, oils that show a low separability number are more likely to be compatible with other oils than are oils with high separability numbers.
SCOPE
1.1 This test method covers the quantitative measurement, either in the laboratory or in the field, of how easily asphaltene-containing heavy fuel oils diluted in toluene phase separate upon addition of heptane. This is measured as a separability number (%) by the use of an optical scanning device.  
1.2 The test method is limited to asphaltene-containing heavy fuel oils. ASTM specification fuels that generally fall within the scope of this test method are Specification D396, Grade Nos. 4, 5, and 6, Specification D975, Grade No. 4-D, and Specification D2880, Grade Nos. 3-GT and 4-GT. Refinery fractions from which such blended fuels are made also fall within the scope of this test method.  
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 to alert fuel suppliers or users to the potential for fuel quality or operational problems or the requirement for preventative or remedial measures, or both.  
5.2 This test method allows assessment of whether antigens generated by microbial activity in the specimens are present within specific defined ranges.  
5.3 This test method measures the presence of microbial and metabolite antigens in a specimen. The antigens are generated from the living cells and metabolites created by fungi and bacteria during growth on fuel. Consequently, the presence of antigens is an indicator of microbial contamination in fuel systems. Antigens are not associated with matter of nonbiological origin.  
5.3.1 Some of the antigens detected by this test method can persist after treatment with a biocide. See 11.4.  
5.4 This test method is semi-quantitative and can be used to determine whether contamination in samples drawn from fuel tanks and systems is negligible or present at moderate or heavy levels.  
5.4.1 Further information on using the test to assess biodeterioration risk is provided in Appendix X1.  
5.5 The significance of these levels to the operator will depend on the fuel type, the sampling location, the equipment or facility sampled, and the specific operating circumstances.  
5.6 Further guidance on interpretation of test results can be found in Guide D6469, in Energy Institute guidelines for the investigation of the microbial content of petroleum fuels, and in the IATA Guidance Material on Microbial Contamination in Aircraft Fuel Tanks.  
5.7 Further guidance on sampling can be found in Practice D7464.  
5.8 Testing can be conducted on a routine basis or to investigate incidents.  
5.9 Microbiological tests are not intended to be used to determine compliance with fuel specifications or lim...
SCOPE
1.1 This test method describes a procedure that can be used in the field or in a laboratory to detect antigens indicative of microbial contamination in liquid fuels, including those blended with synthesized hydrocarbons or biofuels, with kinematic viscosities (at 40 °C) of ≤24 mm2s–1 (for example, Specifications D396, D975, and D1655) 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 Specification D1655, EN590, Specification D975, and ISO 8217:2012.  
1.2 This test method semi-quantitatively assesses the concentration of specific antigens generated by commonly recovered, fuel-associated, aerobic microorganisms during active growth in fuel systems.  
1.2.1 A proprietary formulation of antibodies and antibody mixtures is used to detect three types of microbial antigen contamination: antigens generally found in aerobic bacteria, antigens generally present in common fungi (yeast and molds), and an antigen that is characteristic of Hormoconis resinae (the fungus most commonly associated with fuel biodeterioration).  
1.2.2 Although the antibodies and antibody mixtures are characteristic of diverse types of bacteria and fungi, it is unlikely that they are universal. Recognizing that for every microbe that has been isolated and characterized, it is likely that there are a billion that have not. Consequently, as is the case with all microbiological test methods, this test method does not purport to detect 100 % of the microbes present in a fuel or fuel-associated water sample.  
1.3 For each of the three sets of antigen detected (H. resinae, common fungi, and aerobic bacteria), the test detects whether the antigen concentration present is within set ranges representing negligible, moderate, or heavy microbial contamination.  
1.3.1 For fuel specimens, the antigen concentration ranges detected are 750 µg/L (heavy).  
1.3.2 For specimens of wat...

SIGNIFICANCE AND USE
5.1 This test method measures the concentration of cellular-ATP present in the sample. ATP is a constituent of all living cells, including bacteria and fungi. Consequently, the presence of cellular-ATP is an indicator of total metabolically active microbial contamination in fuels. ATP is not associated with matter of non-biological origin.  
5.2 This test method is similar to Test Method E2694 except for the volumes sampled.  
5.3 This test method differs from Test Method D4012 in that it utilizes filtration and wash steps designed to eliminate interferences that have historically rendered ATP testing unusable with complex organic fluids such as fuel and fuel-associated water.  
5.4 This test method differs from Test Method D7463 in several regards:  
5.4.1 Test Method D7463 reports relative light units (RLU). Consistent with Test Methods D4012 and E2694, this test method reports ATP concentration.  
5.4.2 This test method detects only cellular-ATP and it can be used to detect cellular-ATP in fuels and fuel stocks from which small quantities of water do not separate readily (for example, ethanol blended gasoline containing ≥5 % v/v ethanol). Test Method D7463 cannot be used to recover ATP from fuels from which small quantities of water do not separate readily (for example, ethanol blended gasoline containing ≥5 % v/v ethanol).  
5.4.3 This test method measures cellular-ATP in a single measurement (as pg ATP/mL). Test Method D7463 detects total ATP (as RLU) and extra-cellular ATP (as RLU) using two separate analyses and permits computation of cellular-ATP (as RLU) as the difference between total and extracellular ATP.  
5.4.4 Test Method D7463 suggests a nominal 500 mL fuel sample volume. This test method suggests a nominal 20 mL fuel sample.  
5.5 This test method can be used with all fuels specified in Specifications D396, D975, D1655, D2069, D2880, D3699, D6751, and D7467 and other fuels with nominal viscosities ≤75 cSt at 20° ± 2°.  
5.6 The ATP test pro...
SCOPE
1.1 This test method covers a protocol for capturing, extracting and quantifying the cellular adenosine triphosphate (cellular-ATP) content associated with microorganisms found in fuels and fuel-associated water.  
1.2 The ATP is measured using a bioluminescence enzyme assay, whereby light is generated in amounts proportional to the concentration of cellular-ATP in the samples. The light is produced and measured quantitatively as relative light units (RLU) which are converted by comparison with an ATP standard, computation to pg ATP/mL and optional further transformation to Log10[pg ATP/mL].  
1.3 This test method is equally suitable for use as a laboratory or portable method.  
1.4 This test method is limited to fuels with a nominal viscosity ≤75 cSt at test temperature.  
1.5 This test method detects ATP concentrations in the range of 5.0 pg ATP/mL (≈0.699 log10[pg ATP/mL]) to 100 000 pg ATP/mL (≈5.000 log10[pg ATP/mL]) for 20 mL samples of fuel and 20 pg ATP/mL (≈1.301 log10[pg ATP/mL]) to 400 000 pg ATP/mL (≈5.602 log10[pg ATP/mL]) for 5 mL samples of fuel-associated water.
Note 1: These ranges were calculated with the formula for calculating sample ATP in pg/mL provided in 12.1 based on the minimum recommended RLU for a 1 ng/mL ATP standard when using the reagents specified in Section 7 and the luminometer specified in 6.4 and corrected with a reagent-method blank as determined in Appendix X5.  
1.6 Providing interferences can be overcome, bioluminescence is a reliable and proven method for qualifying and quantifying ATP. This test method does not differentiate between ATP from different sources, for example: from different types of microorganisms, such as bacteria and fungi.  
1.7 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.8 This standard does not purport to address all of the safety concerns, if any, associated with its us...

SIGNIFICANCE AND USE
5.1 This test method describes a sensitive method for estimating the intrinsic stability of an oil. The intrinsic stability is expressed as S-value. An oil with a low S-value is likely to undergo flocculation of asphaltenes when stressed (for example, extended heated storage) or blended with a range of other oils. Two oils each with a high S-value are likely to maintain asphaltenes in a peptized state and not lead to asphaltene flocculation when blended together.  
5.2 This test method can be used by petroleum refiners to control and optimize the refinery processes and by blenders and marketers to assess the intrinsic stability of blended asphaltene-containing heavy fuel oils.
SCOPE
1.1 This test method covers procedures for quantifying the intrinsic stability of the asphaltenes in an oil by automatic instruments using optical detection.  
1.2 This test method is applicable to residual products from thermal and hydrocracking processes, to products typical of Specifications D396 Grades No. 5L, 5H, and 6, and D2880 Grades No. 3-GT and 4-GT, and to crude oils, providing these products contain 0.5 % by mass or greater concentration of asphaltenes (see Test Method D6560).  
1.3 This test method quantifies asphaltene stability in terms of state of peptization of the asphaltenes (S-value), intrinsic stability of the oily medium (So) and the solvency requirements of the peptized asphaltenes (Sa).  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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 for use in the laboratory or field in evaluating distillate fuel cleanliness.  
5.2 A change in filtration performance after storage, pretreatment, or commingling can be indicative of changes in fuel condition.  
5.3 Relative filterability of fuels may vary depending on filter porosity and structure and may not always correlate with results from this test method.  
5.4 Causes of poor filterability in industrial/refinery filters include fuel degradation products, contaminants picked up during storage or transfer, incompatibility of commingled fuels, or interaction of the fuel with the filter media. Any of these could correlate with orifice or filter system plugging, or both.
SCOPE
1.1 This test method covers a procedure for determining the filterability of distillate fuel oils within the viscosity range from 1.70 mm2/s to 6.20 mm2/s (cSt) at 40 °C.
Note 1: ASTM specification fuels falling within the scope of this test method are Specification D396 Grade No. 2, Specification D975 Grade No. 2-D, and Specification D2880 Grade No. 2-GT.
Note 2: The test method has been used with lower viscosity middle distillate fuels such as Specification D396 Grade No. 1, Specification D975 Grade No. 1-D, and Specification D2880 Grade No. 1-GT, but the precision has not been studied and therefore the stated precision has not been validated for these grades.  
1.2 This test method is not applicable to fuels that contain undissolved water.  
1.3 The values stated in SI units are to be regarded as standard.  
1.3.1 Non-SI units, specifically U.S. customary units such as temperature in degrees Fahrenheit and pressure in pounds per square inch gauge (psig), are included for information.  
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 Appreciable amounts of sediment in a residual fuel oil can cause fouling of facilities for handling, and give problems in burner mechanisms. Sediment can accumulate in storage tanks, on filter screens, or on burner parts, resulting in obstruction of the flow of oil from the tank to the burner.
SCOPE
1.1 This test method covers the determination of total sediment up to 0.40 % m/m for distillate fuel oils containing residual components and to 0.50 % m/m in residual fuel oils having a maximum viscosity of 55 cSt (mm2/s) at 100 °C. Some fuels can exceed the maximum filtration time specified in this test method due to factors other than the presence of significant quantities of insoluble organic or inorganic material. This test method can be used for the assessment of total sediment after regimes of fuel pretreatment designed to accelerate the aging process.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see 7.2, 7.3, Annex A1, and X1.6.1.  
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
5.1 The present and growing international governmental requirements to add Fatty Acid Methyl Esters (FAME) to diesel fuel has had the unintended side-effect of leading to potential FAME contamination of fuels in multi-fuel transport facilities such as cargo tankers and pipelines, and industry wide concerns. This has led to a requirement to measure contamination levels in diesel and other fuels to assist custody transfer issues.  
5.2 Analytical methods have been developed with the capability of measuring down to  
5.3 A similar procedure, Test Method D7797, is available for AVTUR in the range 10 mg/kg to 150 mg/kg. Test Method D7797 uses the same apparatus, with a specific model developed for AVTUR.
SCOPE
1.1 This test method specifies a rapid screening method using flow analysis by Fourier Transform Infrared (FA-FTIR) spectroscopy with partial least squares (PLS) processing for the quantitative determination of the fatty acid methyl ester (FAME) contamination of middle distillates, in the range of 20 mg/kg to 1000 mg/kg, and of middle distillates and residual fuels, following dilution, for levels above 0.1 %.
Note 1: Annex A2 describes a dilution procedure to significantly expand the measurement range above 1000 mg/kg for distillates and to enable measurement of residual oils
Note 2: This test method detects all FAME components, with peak IR absorbance at approximately 1749 cm-1 and C8 to C22 molecules, as specified in standards such as D6751 and EN 14214. The accuracy of the test method is based on the molecular mass of C16 to C18 FAME species; the presence of other FAME species with different molecular masses could affect the accuracy.
Note 3: Additives such as antistatic agents, antioxidants, and corrosion inhibitors are measured with the FAME by the FTIR spectrometer. However any potential interference effects of these additives are eliminated by the flow analysis processing.
Note 4: The scope of this test method does not include aviation turbine fuel which is addressed by Test Method D7797.  
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, health, and environmental 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
5.1 Storage stability depends on complex interactions. It varies with feedstock type and source, and the processing used. The rate of degradation may not change uniformly with temperature. Chemical reactions may lead to a change in color followed by the formation of soluble gums and insoluble sediments. Insoluble sediments may overload filters, and plug nozzles and injectors.  
5.2 This test method, which does not require the test sample to be heated, uses a portable apparatus and allows tests to be carried out on site or in the laboratory to give a result within 35 min.  
5.3 The potential beneficial effects of stability additives in fuels may not be recognized by this test method. Therefore, the actual storage stability of middle distillate fuels with stability additives may not be correctly indicated by these test results.  
5.4 The unstable reactive compounds (phenalenes and phenalenones) detected by this test method may be present in fuels containing catalytically cracked or straight run materials and can affect the potential instability of the fuel.  
5.5 If this test method is used by any party for a rapid assessment of stability, it is the responsibility of parties concerned to decide whether or not this procedure yields meaningful results.  
5.6 Interpretation of results and correlation with other test methods is given in Appendix X1.
SCOPE
1.1 This test method covers a procedure3 for the rapid determination of phenalenes and phenalenones in middle distillate fuels, including marine, automotive, heating, and gas turbine fuel such as those specified in Specifications D396, D975, D2069, and D2880. Phenalenes and phenalenones affect the potential instability of fuels, leading to fuel degradation products during storage, which may cause performance problems.  
1.2 This test method is applicable to both dyed and undyed fuels at all points in the distribution chain from refinery to end-user. It is not applicable to fuels containing residual oil. The portable apparatus allows the whole test to be conducted on site or in a laboratory and does not require the test sample to be heated.  
1.3 This test method is suitable for testing samples with a relative absorbance of up to 5.00 absorbance units (AU).
Note 1: The precision of the test method has been established on relative absorbance up to 1.00 AU. For relative absorbance above 1.00 AU the precision may not apply.  
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 for use in the laboratory or in the field to evaluate the cleanliness of distillate fuels, and liquid biofuels, such as biodiesel and diesel blends. This specific test method and the precision statement applies to off-line analysis.
Note 5: These PCMs can be used for high pressure on-line applications as well, however the repeatability (r) and reproducibility (R) for on-line application were not established.  
5.2 An increase in particulate counts can indicate a change in the fuel condition caused for example by contamination during storage or transfer. Potential causes of particulates formation during storage could be “fuel-degradation products,” as described in Specification D975, Appendix X3.  
5.3 High levels of particles can cause filter blockages (especially when the particles are close in size to the filter porosity rating) and have a serious impact on the life of pumps, injectors, pistons, and other moving parts. Knowledge of particle size in relation to the metallurgy can provide vital information, especially if the hardness of particles is also known from other sources.  
5.4 This test method specifies a minimum requirement for reporting measurements in particle size bands (A1.2.1). Some specific applications may require measurements in other particle size bands. The particle count from the test should be carefully interpreted by the user as it can potentially over-state risk of abrasive damage or filter blocking due to counting water droplets as well as hard dirt particles.  
5.5 In situations where there is a requirement for the calibration of the apparatus to be solely in accordance with ISO 11171, Test Methods D7619, IP 565, or IP 577 may be used.
SCOPE
1.1 This test method uses specific particle contamination monitors (PCMs) to count and measure the size of dispersed dirt particles, water droplets and other particulates, in middle distillate fuel, in the overall range from 4 µm to 70 µm and in the size bands ≥4 µm, ≥6 µm, ≥14 µm, and ≥30 µm.
Note 1: The term particle contamination monitor, as used in this test method, is the same as that defined in ISO 21018-4; an instrument that automatically measures the concentrations of particles suspended in a fluid at certain sizes and cannot be calibrated in accordance with ISO 11171 whose output may be as a particle size distribution at limited sizes or as a contamination code.  
1.2 This test method has interim repeatability precision only, see Section 14 for more information.
Note 2: ASTM specification fuels falling within the scope of this test method include Specifications: D975, D1655, D3699, D7467, MIL-DTL-83133, MIL-DTL-5624, and distillate grades of D396 and D2880.
Note 3: For the purposes of this test method, water droplets are counted as particles, and agglomerated particles are detected and counted as a single larger particle. Dirt includes microbial particulates. Although the projected area of a particle is measured, this is expressed as the diameter of a circle for the purposes of this test method. The detector is unable to distinguish between dirt and water particles.
Note 4: This test method may be used for particle sizes bands up to 70 µm, however the interim repeatability has only been determined for the size bands ≥4 µm, ≥6 µm, and ≥14 µm. All measurements are counts per millilitre.  
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 Principl...

SIGNIFICANCE AND USE
5.1 It has long been the practice to include in fuel specifications a requirement that the fuel be clear and bright and free of visible particulate matter (see Note 1). However, there has been no standard method for making this determination so that practices have differed. This test method provides standard procedures for the test.
Note 1: Clean and bright is sometimes used in place of clear and bright. The meaning is identical.  
5.2 Procedure 1 provides a rapid pass/fail method for contamination in a distillate fuel. Procedure 2 provides a gross numerical rating of haze appearance, primarily as a communication tool. Other test methods, including Test Methods D2276, D2709, and D4860, permit quantitative determinations of contaminants. No relationship has been established between Procedure 2 and these quantitative methods.  
5.2.1 Test Method D8148 has established a correlating relationship with Procedure 2 appearance rating numbers by reporting a correlating instrument haze rating (IHR) based upon its spectroscopically determined haze clarity index (HCI). Supporting data can be found in RR:D02-1876.5  
5.3 Limited laboratory evaluations of samples that have failed this clear and bright test indicate that an experienced tester can detect as little as 40 ppm of free water in the fuel.
SCOPE
1.1 This test method covers two procedures for estimating the presence of suspended free water and solid particulate contamination in distillate fuels having distillation end points below 400 °C and an ASTM color of 5 or less.  
1.1.1 Both procedures can be used as field tests at storage temperatures, or as laboratory tests at controlled temperatures.  
1.1.2 Procedure 1 provides a rapid pass/fail method for contamination. Procedure 2 provides a gross numerical rating of haze appearance.  
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, health, and environmental 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.

SCOPE
1.1 Microbiological test methods present challenges that are unique relative to chemical or physical parameters, because microbes proliferate, die off and continue to be metabolically active in samples after those samples have been drawn from their source.  
1.1.1 Microbial activity depends on the presence of available water. Consequently, the detection and quantification of microbial contamination in fuels and lubricants is made more complicated by the general absence of available water from these fluids.  
1.1.2 Detectability depends on the physiological state and taxonomic profile of microbes in samples. These two parameters are affected by various factors that are discussed in this guide, and contribute to microbial data variability.  
1.2 This guide addresses the unique considerations that must be accounted for in the design and execution of interlaboratory studies intended to determine the precision of microbiological test methods designed to quantify microbial contamination in fuels, lubricants and similar low water-content (water activity  
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, health, and environmental 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
5.1 The results (of these tests) can be used to indicate storage stability of these fuels. The tendency of fuels to form gum and deposits in these tests has not been correlated with field performance (and can vary markedly) with the formation of gum and deposits under different storage conditions.
SCOPE
1.1 This test method3 covers the determination of the tendency of aviation reciprocating, turbine, and jet engine fuels to form gum and deposits under accelerated aging conditions. (Warning—This test method is not intended for determining the stability of fuel components, particularly those with a high percentage of low boiling unsaturated compounds, as these may cause explosive conditions within the apparatus.)
Note 1: For the measurement of the oxidation stability (induction period) of motor gasoline, refer to Test Method D525.  
1.2 The accepted SI unit of pressure is the kilo pascal (kPa); the accepted SI unit of temperature is °C.  
1.3 WARNING—Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use caution when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their location.  
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.
SCOPE
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 is used as an indication of free water and sediment suspended as haze, cloudiness, or droplets in middle distillate fuels such as Grades No. 1 and 2 fuel oil (Specification D396), Grades No. 1-D and 2-D diesel fuel (Specification D975), and Grades No. 0-GT, 1-GT, and 2-GT gas turbine fuels (Specification D2880), similar fuels and blendstocks used to make these fuels.  
5.2 Appreciable amounts of free water and sediment in a fuel oil tend to cause fouling of fuel-handling facilities and to give trouble in the fuel system of a burner or engine. An accumulation of sediment in storage tanks and on filter screens can obstruct the flow of oil from the tank to the combustor. Free water in middle distillate fuels can cause corrosion of tanks and equipment, and if detergent is present, the water can cause emulsions or a hazy appearance. Free water can support microbiological growth at fuel-water interfaces in fuel systems. (A) Measured between tips of opposite tubes when in rotating position.(B) “r/min” is the correct SI symbol for the former term “rpm.”
SCOPE
1.1 This test method covers the determination of the volume of free water and sediment (as a percentage of the sample) that is suspended in the bulk fuel in middle distillate fuels with viscosities in the range of 1.0 mm2/s to 4.1 mm2/s at 40 °C (1.0 cSt to 4.1 cSt at 104 °F) and densities in the range of 770 kg/m3 to 900 kg/m3 at 15 °C.  
Note 1: Fuels corresponding to Specification D396 Grades No. 1 and 2, D975 Grades No. 1-D and 2-D, Specification D2880 Grades No. 0-GT, 1-GT and 2-GT, and Specification D3699 Grades No. 1-K and 2-K and similar middle distillate fuels and blendstocks will usually fall in this viscosity and density range. Test Method D1796 is intended for higher viscosity fuel oils.  
1.2 The values stated in SI units are to be regarded as standard.  
1.2.1 Exception—The non-SI values are for information only.  
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, health, and environmental 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
5.1 The test provides a field test to evaluate visually a fuel sample for particulate matter and free water similar to Test Method D4176 plus a numerical rating for free water. High numerical ratings indicate that the fuel is relatively free of free water. The degree of water and particulate contamination can be measured using other methods such as Test Methods D2276, D2709, and D6304.
Note 2: Clean and bright is sometimes used in place of clear and bright. The meaning is identical.  
5.2 The color of the sample does not affect the measurement. Limited laboratory evaluations of samples have determined the degree of free water can be rated in fuels with dark opaque color having a darker rating than five in Test Method D1500.
SCOPE
1.1 This test method covers a rapid, portable means for field and laboratory use to inspect visually for particulate matter and numerically rate free water in aviation turbine and distillate fuels.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see 11.2.3 and Annex A1.  
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
5.1 Asphaltenes are the organic molecules of highest molecular mass and carbon-hydrogen ratio normally occurring in crude petroleum and petroleum products containing residual material. They may give problems during storage and handling if the suspension of asphaltene molecules is disturbed through excess stress or incompatibility. They are also the last molecules in a product to combust completely, and thus may be one indicator of black smoke propensity. Their composition normally includes a disproportionately high quantity of the sulfur, nitrogen, and metals present in the crude petroleum or petroleum product.
SCOPE
1.1 This test method covers a procedure for the determination of the heptane insoluble asphaltene content of gas oil, diesel fuel, residual fuel oils, lubricating oil, bitumen, and crude petroleum that has been topped to an oil temperature of 260 °C (see A1.2.1.1).  
1.2 The precision is applicable to values between 0.50 % m/m and 30.0 % m/m. Values outside this range may still be valid but may not give the same precision values.  
1.3 Oils containing additives may give erroneous results.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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 an indication of thermal oxidative stability of distillate fuels when heated to high temperatures that simulate those that may occur in some types of recirculating engine or burner fuel delivery systems. Results have not been substantially correlated to engine or burner operation. The test method can be useful for investigation of operational problems related to fuel thermal stability.  
5.2 When the test method is used to monitor manufacture or storage of fuels, changes in filter rating values can indicate a relative change in inherent stability. Storage stability predictions are more reliable when correlated to longer-term storage tests, for example, Test Method D4625, or other lower temperature, long-term tests. When fuel samples are freshly produced, aging for 180 min, instead of the traditional 90 min interval, tends to give a result correlating more satisfactorily with the above methods (see Appendix X2).  
5.3 The test method uses a filter paper with a nominal porosity of 11 μm, which will not capture all of the sediment formed during aging but allows differentiation over a broad range. Reflectance ratings are also affected by the color of filterable insolubles, which may not correlate to the mass of the material filtered from the aged fuel sample. Therefore, no quantitative relationship exists between the pad rating and the gravimetric mass of filterable insolubles.
SCOPE
1.1 This test method covers relative stability of middle distillate fuels under high temperature aging conditions with limited air exposure. This test method is suitable for all No. 1 and No. 2 grades in Specifications D396, D975, D2880, and D3699. It is also suitable for similar fuels meeting other specifications.  
1.2 This test method is not suitable for fuels whose flash point, as determined by Test Methods D56, D93, or D3828, is less than 38 °C. This test method is not suitable for fuels containing residual oil.  
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 Exception—The maximum vacuum includes inch-pound units in 6.5 and 11.2.  
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 In general, wherever the possibility exists of water getting mixed with products/material (covered under 1.1) the results obtained by this test method will indicate the degree to which corrosion of iron components can be expected.  
5.2 Test also determines the antirust properties of products/material (covered under 1.1) in preparation for the various stages through which the tested product may pass prior to or during its transport through a pipeline.  
5.3 Test results are also meant to show whether or not the dosage levels and type of iron corrosion inhibitor added to a product/material (covered under 1.1) is sufficient for achieving the desired protection of affected assets such as storage tanks, process lines, and shipment systems.
SCOPE
1.1 This test method covers an accelerated laboratory and field procedure for the determination of corrosion of iron, in the presence of water, on samples such as gasoline and gasoline blended with 10 % ethanol, E10 (Specification D4814); gasoline-blend components (except butane); diesel fuel and biodiesel B5, except Grade No. 4-D (Specification D975); biodiesel B6 to B20 (Specification D7467); diesel-blend component such as light cycle-oil; No. 1 fuel oil, No. 2 fuel oil (Specification D396); aviation turbine fuel (Specification D1655).  
1.2 The values stated in SI units are to be regarded as the standard.  
1.2.1 Exception—Values in parentheses are for information only.  
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, health, and environmental 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
5.1 Residual fuel oils can contain H2S in the liquid phase, and this can result in hazardous vapor phase levels of H2S in storage tank headspaces. The vapor phase levels can vary significantly according to the headspace volume, fuel temperature, and agitation. Measurement of H2S levels in the liquid phase provides a useful indication of the residual fuel oil’s propensity to form high vapor phase levels, and lower levels in the residual fuel oil will directly reduce risk of H2S exposure. It is critical, however, that anyone involved in handling fuel oil, such as vessel owners and operators, continue to maintain appropriate safety practices designed to protect the crew, tank farm operators and others who can be exposed to H2S.  
5.1.1 The measurement of H2S in the liquid phase is appropriate for product quality control, while the measurement of H2S in the vapor phase is appropriate for health and safety purposes.  
5.2 This test method was developed so refiners, fuel terminal operators and independent testing laboratory personnel can analytically measure the amount of H2S in the liquid phase of residual fuel oils.
Note 1: Test Method D6021 is one of three test methods for quantitatively measuring H2S in residual fuels:
1) Test Method D5705 is a simple field test method for determining H2S levels in the vapor phase.
2) Test Method D7621 is a rapid test method to determine H2S levels in the liquid phase.  
5.3 H2S concentrations in the liquid and vapor phase attempt to reach equilibrium in a static system. However, this equilibrium and the related liquid and vapor concentrations can vary greatly depending on temperature and the chemical composition of the liquid phase. A concentration of 1 mg/kg (μg/g) (ppmw) of H2S in the liquid phase of a residual fuel can typically generate an actual gas concentration of >50 μL/L(ppmv) to 100 μL/L(ppmv) of H2S in the vapor phase, but the equilibrium of the vapor phase is disrupted the moment a vent or access point is opened ...
SCOPE
1.1 This test method covers a method suitable for measuring the total amount of hydrogen sulfide (H2S) in heavy distillates, heavy distillate/residual fuel blends, or residual fuels as defined in Specification D396 Grade 4, 5 (Light), 5 (Heavy), and 6, when the H2S concentration in the fuel is in the 0.01 μg/g (ppmw) to 100 μg/g (ppmw) range.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see 7.5, 8.2, 9.2, 10.1.4, and 11.1.  
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
5.1 The true significance of this test method for determining gum in motor gasoline is not firmly established. It has been proved that high gum can cause induction-system deposits and sticking of intake valves, and in most instances, it can be assumed that low gum will ensure absence of induction-system difficulties. The user should, however, realize that the test method is not of itself correlative to induction-system deposits. The primary purpose of the test method, as applied to motor gasoline, is the measurement of the oxidation products formed in the sample prior to or during the comparatively mild conditions of the test procedure. Since many motor gasolines are purposely blended with nonvolatile oils or additives, the heptane extraction step is necessary to remove these from the evaporation residue so that the deleterious material, gum, may be determined. With respect to aviation turbine fuels, large quantities of gum are indicative of contamination of fuel by higher boiling oils or particulate matter and generally reflect poor handling practices in distribution downstream of the refinery.
SCOPE
1.1 This test method covers the determination of the existent gum content of aviation fuels, and the gum content of motor gasolines or other volatile distillates in their finished form, (including those containing alcohol and ether type oxygenates and deposit control additives—see Note 7 for additional information) at the time of test.  
1.2 Provisions are made for the determination of the heptane insoluble portion of the residue of non-aviation 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.  
1.3.1 The accepted SI unit of pressure is the Pascal (Pa); the accepted SI unit for temperature is degrees Celsius.  
1.4 WARNING—Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use caution when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their location.  
1.5 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. For specific warning statements, see 6.4, 7.4, and 9.1.  
1.6 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 It has long been the practice to include in fuel specifications a requirement that the fuel is clear and bright.  
5.2 One primary cause for failure to meet this specification requirement is the occurrence of a cloudy or hazy appearance caused by suspended solid particulates or water or some combination of both.  
5.2.1 This cloudiness or haze can range from barely visible to opaque.  
5.3 This test method provides an objective analytical means for providing a haze rating that does not depend on subjective visual ratings that typically vary with operator and lighting conditions.
SCOPE
1.1 This test method covers a spectroscopic procedure for determining the level of suspended water and particulate contamination (haze) in liquid middle distillate fuels including those blended with synthesized hydrocarbons or biofuels.  
1.1.1 An ordinal, whole-number, Instrument Haze Rating (IHR) from 1 to 6 and a Haze Clarity Index (HCI) from 50.0 to 100.0 are determined on a test specimen at a temperature of 22.0 °C ± 2.0 °C.
1.1.1.1 The stated precision only applies at this temperature.
1.1.1.2 Fuels analyzed at other test specimen temperatures may not be as precise.  
1.2 The values stated in SI units are to be regarded as standard. Other units of measurement included in this standard are defined in Section 3.  
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, health, and environmental 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
5.1 Some substances that are soluble or appear to be soluble in biodiesel fuel blendstock (B100) at room temperature will, upon cooling to temperatures above the cloud point or standing at room temperature for extended periods, come out of solution. This phenomenon has been observed in both B100 and biodiesel blends. These substances can cause filter plugging. This method provides an accelerated means of assessing the presence of these substances in B100 and their propensity to plug filters.  
5.1.1 Biodiesel fuel blendstocks that yield short filtration times are expected to give satisfactory operation of biodiesel blends at least down to the cloud point of the biodiesel blends.  
5.2 The test method can be used in specifications as a means of controlling levels of minor filter plugging components in biodiesel and biodiesel blends.
SCOPE
1.1 This test method covers the determination by filtration time after cold soak for the suitability of biodiesel fuel blendstock (B100) that meets all other requirements of Specification D6751 and has a cloud point below 20 °C (68 °F) to provide adequate low temperature operability performance to at least the cloud point of the finished blend.  
1.2 The values stated in SI units are to be regarded as standard. Non-SI units are given for information only.  
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, health, and environmental 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
5.1 This test method is intended for use in the laboratory or in the field for evaluating the cleanliness of distillate fuels, and liquid bio fuels. It is not applicable to on or in-line applications.  
5.2 This test method offers advantage over traditional filtration methods in that it is a precise rapid test, and advantage over visual methods as it is not subjective.  
5.3 An increase in particle counts can indicate a change in the fuel condition caused by storage or transfer for example.  
5.4 High levels of particles can cause filter blockages and have a serious impact on the life of pumps, injectors, pistons and other moving parts. Knowledge of particle size in relation to the metallurgy can provide vital information especially if the hardness of particles is also known from other sources.  
5.5 This test method specifies a minimum requirement for reporting measurements in particle size bands (see A1.1.2). Some specific applications may require measurements in other particle size bands.  
5.6 Obtaining a representative sample and following the recommended sample and test specimen preparation procedures and timescales is particularly important with particle counting methods. (See Sections 8, 10, 14.1.4 and Note 8.)  
5.7 This test method can also be used to estimate the total particulate counts excluding free water droplets in aviation turbine fuels by a chemical pretreatment of the fuel. See Appendix X2.
SCOPE
1.1 This test method uses a specific automatic particle counter2 (APC) to count and measure the size of dispersed dirt particles, water droplets and other particles, in light and middle distillate fuel, and bio fuels such as biodiesel and biodiesel blends, in the overall range from 4 µm(c) to 100 µm(c) and in the size bands ≥4 µm(c), ≥6 µm(c), and ≥14 µm(c).
Note 1: ASTM and military specification fuels falling within the scope of this test method include Specifications: D975 grades 1D and 2D, D1655, D3699, D4814 (see 14.1.1.1), D6751, D7467, distillate grades of D396 and D2880, MIL-DTL-83133, and MIL-DTL-16884.
Note 2: For the purposes of this test method, water droplets are counted as particles, and agglomerated particles are detected and counted as a single larger particle. Dirt includes biological particles. Although the projected area of a particle is measured, this is expressed as the diameter of a sphere for the purposes of this test method.
Note 3: The notation (c), used with particle sizes, is used to denote that the apparatus has been calibrated in accordance with ISO 11171. Strictly this only applies to particles up to 50 µm.
Note 4: This test method may be used for particle sizes bands up to 100 µm(c), however the precision has only been determined for the size bands ≥4 µm(c), ≥6 µm(c), and ≥14 µm(c). All measurements are per millilitre.  
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, health, and environmental 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
5.1 This guide provides a protocol for detecting, characterizing, and quantifying nucleic acids (that is, DNA) of living and recently dead microorganisms in fuels and fuel-associated waters by means of a culture independent qPCR procedure. Microbial contamination is inferred when elevated DNA levels are detected in comparison to the expected background DNA level of a clean fuel and fuel system.  
5.2 A sequence of protocol steps is required for successful qPCR testing.  
5.2.1 Quantitative detection of microorganisms depends on the DNA-extraction protocol and selection of appropriate oligonucleotide primers.  
5.2.2 The preferred DNA extraction protocol depends on the type of microorganism present in the sample and potential impurities that could interfere with the subsequent qPCR reaction.  
5.2.3 Primers vary in their specificity. Some 16S and 18S RNA gene regions present in the DNA of prokaryotic and eukaryotic microorganisms appear to have been conserved throughout evolution and thus provide a reliable and repeatable target for gene amplification and detection. Amplicons targeting these conserved nucleotide sequences are useful for quantifying total population densities. Other target DNA regions are specific to a metabolic class (for example, sulfate reducing bacteria) or individual taxon (for example, the bacterial species Pseudomonas aeruginosa). Primers targeting these unique nucleotide sequences are useful for detecting and quantifying specific microbes or groups of microbes known to be associated with biodeterioration.  
5.3 Just as the quantification of microorganisms using microbial growth media employs standardized formulations of growth conditions enabling the meaningful comparison of data from different laboratories (Practice D6974), this guide seeks to provide standardization to detect, characterize, and quantify nucleic acids associated with living and recently dead microorganisms in fuel-associated samples using qPCR.
Note 3: Many primers, an...
SCOPE
1.1 This guide covers procedures for using quantitative polymerase chain reaction (qPCR), a genomic tool, to detect, characterize and quantify nucleic acids associated with microbial DNA present in liquid fuels and fuel-associated water samples.  
1.1.1 Water samples that may be used in testing include, but are not limited to, water associated with crude oil or liquid fuels in storage tanks, fuel tanks, or pipelines.  
1.1.2 While the intent of this guide is to focus on the analysis of fuel-associated samples, the procedures described here are also relevant to the analysis of water used in hydrotesting of pipes and equipment, water injected into geological formations to maintain pressure and/or facilitate the recovery of hydrocarbons in oil and gas recovery, water co-produced during the production of oil and gas, water in fire protection sprinkler systems, potable water, industrial process water, and wastewater.  
1.1.3 To test a fuel sample, the live and recently dead microorganisms must be separated from the fuel phase which can include any DNA fragments by using one of various methods such as filtration or any other microbial capturing methods.  
1.1.4 Some of the protocol steps are universally required and are indicated by the use of the word must. Other protocol steps are testing-objective dependent. At those process steps, options are offered and the basis for choosing among them are explained.  
1.2 The guide describes the application of quantitative polymerase chain reaction (qPCR) technology to determine total bioburden or total microbial population present in fuel-associated samples using universal primers that allow for the quantification of 16S and 18S ribosomal RNA genes that are present in all prokaryotes (that is, bacteria and archaea) and eucaryotes (that is, mold and yeast collectively termed fungi), respectively.  
1.3 This guide describes laboratory protocols. As described in Practice D7464, the...

SIGNIFICANCE AND USE
5.1 The mass of particulates present in a fuel is a significant factor, along with the size and nature of the individual particles, in the rapidity with which fuel system filters and other small orifices in fuel systems can become plugged. This test method provides a means of assessing the mass of particulates present in a fuel sample.  
5.2 The test method can be used in specifications and purchase documents as a means of controlling particulate contamination levels in the fuels purchased.
SCOPE
1.1 This test method covers the determination of the mass of particulate contamination in B100 biodiesel in accordance with Specification D6751 and BXX blends that are prepared against all No. 1 and No. 2 grade fuels allowed within Specifications D396 and D975.
Note 1: Middle distillate fuels with flash points less than 38 °C have been ignited by discharges of static electricity when the fuels have been filtered through inadequately bonded or grounded glass fiber filter systems. See Guide D4865 for a more detailed discussion of static electricity formation and discharge.  
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, health, and environmental 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
5.1 This is the first ASTM standard test method for assessing the mass quantity of particulates in middle distillate fuels. Test Method D5452 and its predecessor Test Method D2276 were developed for aviation fuels and used 1 gal or 5 L of fuel sample. Using 1 gal of a middle distillate fuel, which can contain greater particulate levels, often required excessive time to complete the filtration. This test method used about a quarter of the volume used in the aviation fuel methods.  
5.2 The mass of particulates present in a fuel is a significant factor, along with the size and nature of the individual particles, in the rapidity with which fuel system filters and other small orifices in fuel systems can become plugged. This test method provides a means of assessing the mass of particulates present in a fuel sample.  
5.3 The test method can be used in specifications and purchase documents as a means of controlling particulate contamination levels in the fuels purchased. Maximum particulate levels are specified in several military fuel specifications.
SCOPE
1.1 This test method covers the determination of the mass of particulate contamination in a middle distillate fuel by filtration. This test method is suitable for all No. 1 and No. 2 grades in Specifications D396, D975, D2880 and D3699 and for grades DMA and DMB in Specification D2069.  
1.2 This test method is not suitable for fuels whose flash point as determined by Test Methods D56, D93 or D3828 is less than 38 °C.
Note 1: Middle distillate fuels with flash points less than 38 °C have been ignited by discharges of static electricity when the fuels have been filtered through inadequately bonded or grounded membrane filter systems. See Test Methods D2276 and D5452 for means of determining particulate contamination in Specification D1655 aviation turbine fuels and other similar aviation fuels. See Guide D4865 for a more detailed discussion of static electricity formation and discharge.  
1.3 This test method has not been validated for testing biodiesel, such as meeting Specification D6751 or blends of middle distillates and biodiesel, such as meeting Specification D7467, or both. Test Method D7321 has been determined to be suitable for testing B100 and all blends of middle distillates and biodiesel.
Note 2: No. 1 and No. 2 grades in Specifications D396 or D975 currently allow up to 5 % biodiesel meeting Specification D6751. Samples containing biodiesel can result in partial dissolution or compromise of the membrane filters and give erroneous results.  
1.4 The precision of this test method is applicable to particulate contaminant levels between 0 g/m3 to 25 g/m3 provided that 1 L samples are used and the 1 L is filtered completely. Higher levels of particulate contaminant can be measured, but are subject to uncertain precision.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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.  
1.7 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 Fuel oxidation and other degradative reactions leading to formation of sediment (and color) are mildly accelerated by the test conditions compared with typical storage conditions. Test results have been shown to predict storage stability more reliably than other more accelerated tests. See Appendix X1 for information on the correlation of test results with actual field storage.  
5.2 Because the storage periods are long (4 weeks to 24 weeks), the test method is not suitable for quality control testing, but does provide a tool for research on storage properties of fuels.  
5.3 Because environmental effects and the materials and nature of tank construction affect storage stability, the results obtained by this test are not necessarily the same as those obtained during storage in a specific field storage situation.
SCOPE
1.1 This test method covers a method for evaluating the inherent storage stability of distillate fuels having flash points above 38 °C (100 °F), by Test Methods D93, and 90 % distilled points below 340 °C (644 °F), by Test Method D86.  
Note 1: ASTM specification fuels falling within the scope of this test method are Specification D396, Grade Nos. 1 and 2; Specification D975, Grades 1-D and 2-D; and Specification D2880, Grades 1-GT and 2-GT.  
1.2 This test method is not suitable for quality control testing but, rather it is intended for research use to shorten storage time relative to that required at ambient storage temperatures.  
1.3 Appendix X1 presents additional information about storage stability and the correlation of Test Method D4625 results with sediment formation in actual field storage.  
1.4 The values given in SI units are to be regarded as the standard.  
1.4.1 Exception—The values in parentheses are for information only.  
1.5 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.  
1.6 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 primary use of this test method is to evaluate new additive packages in specific fuels to ensure that fuel-water separability will not be compromised by the use of the additive package, either at their normal treat rates or at several times the intended treat rate to evaluate the impact of potential overtreatment.  
5.1.1 Water Volume Changes—Using this technique reveal the presence of water-soluble components, such as alcohols, in the fuel.  
5.1.2 Interface Condition Ratings—Using this technique reveal the presence of partially soluble components, such as surfactants, in the fuel.  
5.2 Additives or contaminants that affect the interface could harm water separation properties of fuels in equipment and quickly inhibit the free flow of fuel through filters and injection equipment, causing a decrease in combustion performance.
SCOPE
1.1 This test method covers the evaluation of the tendency of water and fuels with a final boiling point of less than 390 °C, as measured in Test Method D86, to separate cleanly rather than create emulsions when they may contain potential emulsion forming additives or components, or have been additized with potential emulsion forming additives, or components.  
1.2 This test method applies primarily to gasoline, diesel, kerosine, and distillate grades of gas turbine, marine, home heating oils and furnace fuels (see Specifications D396, D975, D2880, D3699, D4814, and D6985). For fuel components such as biodiesel or alcohol, refer to X1.2 and X1.3.  
1.3 This test method is not meant to certify or qualify fuels for sale, but it is intended for use by additive suppliers to determine the need for demulsifier components in their additive packages.  
1.4 This test method is not meant for testing of fuels containing large amounts of aqueous soluble components, such as E85, or for testing of water emulsified fuels, or for testing of aviation fuels.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 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.  
1.7 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 Excessive levels of hydrogen sulfide in the vapor phase above residual fuel oils in storage tanks can result in health hazards, violation of local occupational health and safety regulations, and public complaint. An additional concern is corrosion that can be caused by the presence of H2S during refining or other activities. Control measures to maintain safe levels of H2S require a precise method for the measurement of potentially hazardous levels of H2S in fuel oils. (Warning—Safety. Hydrogen sulfide (H2S) is a very dangerous, toxic, explosive and flammable, colorless and transparent gas which can be found in crude oil and can be formed during the manufacture of the fuel at the refinery and can be released during handling, storage, and distribution. At very low concentrations, the gas has the characteristic smell of rotten eggs. However, at higher concentrations, it causes a loss of smell, headaches, and dizziness, and at very high concentrations, it causes instantaneous death. It is strongly recommended that personnel involved in the testing for hydrogen sulfide are aware of the hazards of vapor-phase H2S and have in place appropriate processes and procedures to manage the risk of exposure.)  
5.2 This test method was developed so refiners, fuel terminal operators, and independent testing laboratory personnel can rapidly and precisely measure the amount of H2S in residual fuel oils and distillate blend stocks, with a minimum of training, in a wide range of locations.  
5.3 Test Method D5705 provides a simple and consistent field test method for the rapid determination of H2S in the residual fuel oils vapor phase. However it does not necessarily simulate the vapor phase H2S concentration of a fuel storage tank nor does it provide any indication of the liquid phase H2S concentration.  
5.4 Test Method D6021 does measure the H2S concentration of H2S in the liquid phase, however it requires a laboratory and a skilled operator to perform the complex procedure an...
SCOPE
1.1 This test method covers procedures (A and B) for the determination of the hydrogen sulfide (H2S) content of fuel oils such as marine residual fuels and blend stocks, with viscosity up to 3000 mm2s-1 at 50 °C, and marine distillate fuels, as measured in the liquid phase.
Note 1: Specification fuels falling within the scope of this test method are: ASTM Specification D396, MIL-DTL-16884, and ISO 8217.  
1.2 Procedure A has been shown to eliminate interferences such as thiols (mercaptans) and alkyl sulfides. Procedure B can give elevated results if such interferences are present (see Annex A2).
Note 2: A procedure for measuring the amount of hydrogen sulfide in crude oil can be found in Appendix X1. Full precision for Appendix X1 has not yet been determined.  
1.3 Valid ranges for the precision are given in Table 2 and Table 3. Measurements can be made outside these ranges however precision has not been determined.  
1.4 Samples containing FAME do not affect the measurement of hydrogen sulfide by this test method.  
1.5 The values stated in SI units are to be regarded as standard. Non-SI units given in parentheses are for information only.  
1.6 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.  
1.7 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 is designed to be used as a rapid measure of the overall relative corrosivity of Ethanol Fuel Blends (Specification D5798) and Denatured Fuel Ethanol (Specification D4806) to iron (steel).  
5.2 The test can be used to compare corrosion inhibitor dosage levels and effectiveness of various corrosion inhibitors as they pertain to protecting iron (steel) materials from corrosion.
SCOPE
1.1 This test method measures the ability of inhibited and uninhibited Ethanol Fuel Blends defined by Specification D5798 and Denatured Fuel Ethanol defined by Specification D4806 to resist corrosion of iron should water become mixed with the fuel, using an accelerated laboratory test method. Corrosion ratings are reported based on a visual, numbered rating scale.  
1.2 The values stated in SI units are to be regarded as standard. The values in parentheses are for information only.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Sections 7 and 8.  
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
5.1 This test method is intended for use in the laboratory or in the field for evaluating the cleanliness of fuels identified in the scope.  
5.2 Detection of particles and water can indicate degradation of the fuel condition. Particles, whether inorganic or organic, can cause fouling of fuel filters and damage pumps, injectors, and pistons. Knowledge of particle size in relation to metallurgy can provide vital information, especially if the hardness of the solid particles are known from other sources.
Note 3: The method includes the detection of water, solids, and air bubbles. The air bubbles are screened out of the data prior to analysis of results, based on shape and transparency, and are not reported in the results.
SCOPE
1.1 This test method uses a direct imaging analyzer to count and measure the size and shape of dispersed solid particles and water droplets in light and middle distillate fuels in the overall range from 4 μm to 100 μm and in size bands of ≥4 μm, ≥6 μm, and ≥14 μm.
Note 1: Particle size data from 0.7 μm through 300 μm is available for use or reporting if deemed helpful.
Note 2: Shape is used to classify particles, droplets, and bubbles and is not a reporting requirement.  
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, health, and environmental 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
5.1 This test method measures the concentration of ATP present in the sample. ATP is a constituent of all living cells including bacteria and fungi. Consequently, the presence of ATP is a reliable indicator of microbial contamination in fuel systems. ATP is not associated with matter of non-biological origin.  
5.2 This test method differs from Test Method D4012 as follows:  
5.2.1 By providing for the rapid determination of ATP present in a fuel (petroleum) sample, a fuel and water mixture sample, fuel-associated bottom water sample, and extracellular ATP freely available in the fuel or aqueous sample matrix;  
5.2.2 By providing for a method to capture, extract, and quantify ATP using self-contained test device and luminometer;  
5.2.3 By providing a method of quantifying ATP present in fuel or water matrices in generally less than 10 min; and  
5.2.4 By providing for the rapid separation of the ATP from chemical interferences that have previously prevented the use of ATP determinations in complex fluids containing hydrocarbons and other organic molecules.  
5.3 This test method does not require the use of hazardous materials and does not generate biohazard waste.  
5.4 This test method can be used to estimate viable microbial biomass, to evaluate the efficacy of antimicrobial pesticides, and to monitor microbial contamination in fuel storage and distribution systems.
SCOPE
1.1 This test method provides a protocol for capturing, concentrating, and testing the adenosine triphosphate (ATP) present in a fuel system sub-sample (that is, test specimen) associated with:  
1.1.1 Microorganisms and hydrophilic particles found in liquid fuels as described in Table X6.1, or  
1.1.2 Microorganisms and hydrophilic particles found in mixture of fuel and associated bottom water or just associated bottom water.  
1.1.3 ATP detected by this bioluminescence test can be derived from cellular ATP, extra-cellular ATP, or some combination of both.  
1.1.4 Cellular and extra-cellular ATP utilized to perform ATP bioluminescence are captured and concentrated from a fuel system sample into an aqueous test specimen (that is, sub-sample) for testing. For example, for a fuel system sample that does not contain any visible fuel associated bottom water, the aqueous test specimen is the capture solution itself described in 8.2.1.1. For fuel system samples that are a mixture of fuel and associated bottom water (that is, free water), the test specimen is an aliquant of the capture solution and associated bottom water.  
1.2 The ATP is measured using a patented bioluminescence enzyme assay, whereby light is generated in amounts proportional to the concentration of ATP in the sample. The light is produced and measured quantitatively using dedicated ATP test pens2 and a dedicated luminometer2 and reported in (instrument specific) Relative Light Units.  
1.3 This test method is equally suitable for use in the laboratory or field.  
1.4 Although bioluminescence is a reliable and proven technology, this method does not differentiate ATP from bacteria or fungi.  
1.5 For water or capture solution samples, the concentration range of ATP detectable by this test method is 1 × 10–11  M to 3 × 10–8  M which is equivalent to 1 × 10–14  moles/mL to 3 × 10–11  moles/mL for water samples or capture solution. Assuming testing on fuel phase is performed on a 500 mL volume of fuel the equivalent concentrations is fuel would be: 6 × 10–11 M to 2 × 10–14 M.  
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6.1 There is one exception—Relative Light Unit (RLU) as defined in 3.1.19.  
1.7 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 r...

SIGNIFICANCE AND USE
5.1 This test method is intended for use in evaluating the cleanliness of middle distillate fuels for quality control purposes.  
5.2 The filter media specified in this procedure is suitable for the materials in the scope.  
5.3 A change in filtration performance after storage or pretreatment can be indicative of changes of fuel condition.  
5.4 The filterability of fuels varies depending on filter porosity and structure. Therefore, results from this test method might not correlate with full-scale filtration; however, results from this test might help identify fuels that can reduce filter life.  
5.5 Causes of poor filterability in industrial/refinery filters include fuel degradation products, contaminants (including water) picked up during storage or transfer, effects due to temperature or composition for diesel, incompatibility of commingled fuels, or interaction of the fuel with the filter media. Any of these could correlate with orifice or filter system plugging, or both.  
5.6 The results of the EFBT test can range from 1 for a fuel with very good filterability, to over 30 for a fuel with poor filterability. The selection of a single EFBT number to define a pass or fail criteria is not possible, as this will be dependent on the fuel type and application specifics. The correlation between filter life and EFBT number is, therefore, dependent on many variables stemming from the design and use of the engine. Some factors like pressures and particle size removal required come from the fuel system design while others are a result of the duty cycle and environment where the engine is deployed. As an example, a large displacement HPCR (High-Pressure Common Rail) engine in continuous operation may have cleanliness needs much greater than that of a medium or light-duty engine in occasional use. In each case, the expected EFBT value may be different. An EFBT value of D2068 method (Appendix X1).
SCOPE
1.1 This test method covers a procedure for the determination of the Enhanced Filter Blocking Tendency (EFBT) and the filterability of middle distillate fuel oils. This test is applicable to fuels within the viscosity range of 1.3 mm2/s to 6.0 mm2/s at 40 °C.
Note 1: ASTM specification fuels falling within the scope of this test method are: Specification D396 Grades No 1 and 2; Specification D975 Grades No. 1-D S15 and S500, and No. 2-D S15 and S500; Specification D2880 Grades No. 1-GT and No. 2-GT.  
1.2 This test method has interim repeatability only. For more information, see Section 12.  
1.3 This test method is not applicable to fuels that contain free (undissolved) water (see 7.3).  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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 Understanding the stability and compatibility of a petroleum product (crude oil or refinery stream, or both) is critical to facilities that receive multiple types of products and perform blending and processing operations. Blending incompatible streams can cause asphaltene precipitation with potential consequences such as but not limited to: refinery unit fouling, processing problems, throughput reduction, emulsion stabilization, pipeline and tank deposition, and equipment fouling.  
5.2 The ability to predict the results of blending operations allows operators to anticipate potential problems and mitigate those problems prior to receiving the products. It also helps facilities to manage their product movements in the most effective manner to avoid future issues.  
5.3 Some petroleum products are unstable without blending and understanding the stability of a product in terms of asphaltene precipitation is an important factor in product selection for refining. Products with poor stability can contribute to refinery unit fouling as well as the overall processibility and yield of that product.
SCOPE
1.1 This test method covers the use of a basic microscope to determine the asphaltene solvency properties of bitumen, crude oil, condensate or related products, or the combinations thereof. These properties can be used to calculate the solubility parameters required to calculate and predict asphaltene stability for blending purposes, refinery unit fouling, processibility, emulsion stabilization, pipeline and tank deposition, and equipment fouling. If the solubility properties are known for two products, then the compatibility of potential blend ratios can be predicted.  
1.2 This test method is limited to products that allow handling at atmospheric pressure and room temperature conditions without a significant loss of light end components. Loss of light ends will result in changes in the solubility properties of the product and may alter or bias the results, or both. Samples with vapor pressures (VPCR4 at 37.8 °C using Test Method D6377) greater than 100 kPa are not suitable for use with this test method.  
1.3 This test method is primarily suited to products that are freely flowing at test conditions. Samples that are too viscous to flow at test conditions, such as semi-solids, may need to be heated to allow handling (See Annex A1.)  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.5 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.  
1.6 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 Residual fuel oils can contain H2S in the liquid phase and this can result in hazardous vapor phase levels of H2S in storage tank headspaces. The vapor phase levels can vary significantly according to the headspace volume, fuel temperature and agitation. Measurement of H2S levels in the liquid phase provides a useful indication of the residual fuel oil’s propensity to form high vapor phase levels, and lower levels in the residual fuel oil will directly reduce risk of H2S exposure. It is critical, however, that anyone involved in handling fuel oil, such as vessel owners and operators, continue to maintain appropriate safety practices designed to protect the crew, tank farm operators and others who can be exposed to H2S.  
5.1.1 The measurement of H2S in the liquid phase is appropriate for product quality control, while the measurement of H2S in the vapor phase is appropriate for health and safety purposes.  
5.2 This test method was developed to provide refineries, fuel terminals and independent testing laboratories, which do not have access to analytical instruments such as a gas chromatograph, with a simple and consistent field test method for the rapid determination of H2S in the vapor phase above residual fuel oils.
Note 1: D5705 is one of three test methods for quantitatively measuring H2S in residual fuels:
1) Test Method D6021 is an analytical test method to determine H2S levels in the liquid phase.
2) Test Method D7621 is a rapid test method to determine H2S levels in the liquid phase.
Note 2: Because of the reactivity, absorptivity and volatility of H2S, any measurement method only provides an H2S concentration at a given moment in time.  
5.3 This test method does not necessarily simulate the vapor phase H2S concentration in a fuel storage tank. It does, however, provide a level of consistency so that the test result is only a function of the residual fuel oil sample and not the test method, operator, or location. No general correlation can b...
SCOPE
1.1 This test method covers the field determination of hydrogen sulfide (H2S) in the vapor phase (equilibrium headspace) of a residual fuel oil sample.  
1.2 The test method is applicable to liquids with a viscosity range of 5.5 mm2/s at 40 °C to 50 mm2/s at 100 °C. The test method is applicable to fuels conforming to Specification D396 Grade Nos. 4, 5 (Heavy), and 6.  
1.3 The applicable range is from 5 μmol/mol to 4000 μmol/mol (micromoles per mole) (5 ppm v/v to 4000 ppm v/v (parts per million by volume)).  
1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.  
1.5 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.  
1.6 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 for use in evaluating the cleanliness of middle distillate fuels, and biodiesel and biodiesel blends for specifications and quality control purposes.  
5.2 The filter media specified in the three procedures are all suitable for the materials in the Scope. Specifications calling up this test method should state the procedure required.  
5.3 A change in filtration performance after storage or pretreatment can be indicative of changes of fuel condition.  
5.4 The filterability of fuels varies depending on filter porosity and structure and therefore results from this test method might not correlate with full-scale filtration.  
5.5 Causes of poor filterability in industrial/refinery filters include fuel degradation products, contaminants (including water) picked up during storage or transfer, effects due to temperature or composition for bio fuels, incompatibility of commingled fuels, or interaction of the fuel with the filter media. Any of these could correlate with orifice or filter system plugging, or both.  
5.6 The results of the FBT test can range from 1 with a fuel with very good filterability, to over 100 for a fuel with poor filterability. The selection of a single FBT number to define a pass or fail criteria is not possible as this will be dependent on the fuel type and applications.
SCOPE
1.1 This test method covers three procedures for the determination of the filter blocking tendency (FBT) and filterability of middle distillate fuel oils and liquid fuels such as biodiesel and biodiesel blends. The three procedures and associated filter types are applicable to fuels within the viscosity range of 1.3 mm2 to 6.0 mm2/s at 40 °C.
Note 1: ASTM specification fuels falling within the scope of this test method are: Specification D396 Grades No 1 and 2; Specification D975 Grades 1-D, low sulfur 1-D and 2-D; Specification D2880 Grades 1-GT and 2-GT; Specification D6751.  
1.2 This test method is not applicable to fuels that contain free (undissolved) water (see 7.3).  
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 The results of this test method are useful in ranking a specific fuel sample against other specific fuel samples or standards when tested under identical conditions. Specific fuel samples containing dispersant additives, such as dispersant-containing stability additives, have shown inaccurate ranking against fuel samples that do not contain dispersant additives using this test method.3 This test method is not meant to relate a specific fuel to specific field handling and storage conditions. The formation of insolubles is affected by the material present in the storage container and by the ambient conditions. Since this test method is conducted in glass under standardized conditions, the results from different fuels can be compared on a common basis.
SCOPE
1.1 This test method covers a procedure for assessing the potential storage stability of middle distillate fuels such as Grade No. 1D and Grade No. 2D diesel fuels, in accordance with Specification D975.  
1.2 This test method is applicable to either freshly refined fuels or fuels already in storage.  
1.3 This test method is suitable for fuels containing stabilizer additives as well as fuels containing no such additives. However, fuels additized with dispersant additives, including dispersant-containing stability additives, may be ranked inaccurately using this test method compared to fuels that are not additized with dispersant additives.  
1.4 Appendix X1 provides information on other suggested test times and temperatures for which this test method may be used.  
1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.  
1.6 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. For specific warning statements, see 4.1, 6.2, 6.3, and 7.4.  
1.7 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 four procedures in this test method are used alone or in combination to identify fuels or blends that could result in excessive centrifuge loading, strainer plugging, tank sludge formation, or similar operating problems.  
5.2 A spot rating of Number 3 or higher on a finished fuel oil by the cleanliness procedure indicates that the fuel contains excessive suspended solids and is likely to cause operating problems.  
5.3 Although a fuel may test clean when subjected to the cleanliness procedures (manual and automated), suspended solids can precipitate when the fuel is mixed with a blend stock. Evidence of such incompatibility is indicated by a spot rating of Number 3 or higher in the compatibility procedures (manual and automated).
SCOPE
1.1 This test method covers separate procedures for determining the cleanliness of residual fuel oil and the compatibility of a residual fuel oil with a blend stock. It is applicable to residual fuel oils with viscosities up to 50 cSt (1 cSt = 1 mm2s) at 100 °C. This test method describes two protocols: one manual and one automated.
Note 1: This test method has not been evaluated for heavy distillate having the propensity to leave a wax sediment on the filter paper and contain no residual asphaltene.  
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, health, and environmental 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
5.1 This guide provides information addressing the conditions that lead to fuel microbial contamination and biodegradation and the general characteristics of and strategies for controlling microbial contamination. It compliments and amplifies information provided in Practice D4418 on handling gas-turbine fuels. More detailed information may be found in Guidelines for the Investigation of Microbial Content of Liquid Fuels and for the Implementation of Avoidance and Remedial Strategies, 3rd Ed.,10 ASTM Manual 47, and Passman, 2019.11  
5.2 This guide focuses on microbial contamination in refined petroleum products and product handling systems. Uncontrolled microbial contamination in fuels and fuel systems remains a largely unrecognized but costly problem at all stages of the petroleum industry from crude oil production through fleet operations and consumer use. This guide introduces the fundamental concepts of fuel microbiology and biodeterioration control.  
5.3 This guide provides personnel who are responsible for fuel and fuel system stewardship with the background necessary to make informed decisions regarding the possible economic or safety, or both, impact of microbial contamination in their products or systems.
SCOPE
1.1 This guide provides personnel who have a limited microbiological background with an understanding of the symptoms, occurrence, and consequences of chronic microbial contamination. The guide also suggests means for detection and control of microbial contamination in fuels and fuel systems. This guide applies primarily to gasoline, aviation, boiler, industrial gas turbine, diesel, marine, furnace fuels and blend stocks (see Specifications D396, D910, D975, D1655, D2069, D2880, D3699, D4814, D6227, and D6751), and fuel systems. However, the principles discussed herein also apply generally to crude oil and all liquid petroleum fuels. ASTM Manual 472 provides a more detailed treatment of the concepts introduced in this guide; it also provides a compilation of all of the standards referenced herein that are not found in the Annual Book of ASTM Standards, Section Five on Petroleum Products and Lubricants.  
1.2 This guide is not a compilation of all of the concepts and terminology used by microbiologists, but it does provide a general understanding of microbial fuel contamination.  
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 Representative samples of fuel products and associated substances are required for the determination of microbial contamination in fuels and fuel systems in order to accurately assess the biodeterioration risk posed to the fuel, fuel-system components or both. Uncontrolled microbial contamination can affect fuel specification properties adversely.6 As discussed in Guide D6469, microbes can cause a variety of operational problems, including filter plugging and microbially influenced corrosion (MIC), the latter of which causes valve failure, tank and pipeline failure.  
5.2 These practices for microbiological sampling decrease the risk of contaminating samples with extraneous microbes, thereby increasing the probability that the original microbial population in the sample does not change significantly between the time of sampling and the time of testing.  
5.3 The objective of sampling for microbiological testing is to obtain representative samples that are likely to reflect the degree and nature of microbial contamination in the system from which the samples are collected. Manual 477 addresses the rationale for and design of microbial contamination programs. Recognizing that microbiological contamination is not distributed uniformly throughout fuel systems, both the number and types of samples collected will normally be different from the samples collected per Practice D4057 in order to determine whether product meets specifications.  
5.4 The physical, chemical and microbiological property tests to be performed on a sample will dictate the sampling procedures, the sample quantity required, and many of the sample handling requirements.  
5.5 Fuel systems are not normally designed to facilitate optimal microbiological sampling. Consequently, the selection of sampling device and sample source reflect compromises between accessibility and suitability for meeting the sample collection objective.  
5.6 The guidance provided in Practice D4057 generally applies to ...
SCOPE
1.1 This practice covers aspects of sample device preparation and sample handling that prevent samples from becoming contaminated with microorganisms not originally contained within the sample.  
1.2 This practice also covers sample handling considerations that reflect the perishability of samples collected for microbiological testing.  
1.3 This practice supplements Practice D4057 by providing guidance specific to the manual sampling of fuels when samples are to be tested for microbial contamination.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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 Biodeteriogenic microbes infecting fuel systems typically are most abundant within slime accumulations on system surfaces or at the fuel-water interface (Guide D6469). However, it is often impractical to obtain samples from these locations within fuel systems. Although the numbers of viable bacteria and fungi recovered from fuel-phase samples are likely to be several orders of magnitude smaller than those found in water-phase samples, fuel-phase organisms are often the most readily available indicators of fuel and fuel system microbial contamination.  
5.2 Growth Medium Selectivity—Guide E1326 discusses the limitations of growth medium selection. Any medium selected will favor colony formation by some species and suppress colony formation by others. As noted in 6.3, physical, chemical and physiological variables can affect viable cell enumeration test results. Test Method D7463 provides a non-culture means of quantifying microbial biomass in fuels and fuel associated water.  
5.3 Since a wide range of sample sizes, or dilutions thereof, can be analyzed by the membrane filter technique (Test Methods D5259 and F1094), the test sensitivity can be adjusted for the population density expected in the sample.  
5.4 Enumeration data should be used as part of diagnostic efforts or routine condition monitoring programs. Enumeration data should not be used as fuel quality criteria.
SCOPE
1.1 This practice covers a membrane filter (MF) procedure for the detection and enumeration of Heterotrophic bacteria (HPC) and fungi in liquid fuels with kinematic viscosities ≤24 mm2 · s-1 at ambient temperature.  
1.2 This quantitative practice is drawn largely from IP Method 385 and Test Method D5259.  
1.3 This test may be performed either in the field or in the laboratory.  
1.4 The ability of individual microbes to form colonies on specific growth media depends on the taxonomy and physiological state of the microbes to be enumerated, the chemistry of the growth medium, and incubation conditions. Consequently, test results should not be interpreted as absolute values. Rather they should be used as part of a diagnostic or condition monitoring effort that includes other test parameters, in accordance with Guide D6469.  
1.5 This practice offers alternative options for delivering fuel sample microbes to the filter membrane, volumes or dilutions filtered, growth media used to cultivate fuel-borne microbes, and incubation temperatures. This flexibility is offered to facilitate diagnostic efforts. When this practice is used as part of a condition monitoring program, a single procedure should be used consistently.  
1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.7 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.  
1.8 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 Asphaltenes are naturally occurring materials in crude petroleum and petroleum products containing residual material. The asphaltenes are usually present in colloidal suspensions, but they may agglomerate and flocculate if the suspension of asphaltene molecules is disturbed through excess stress or incompatibility. This test method provides compatibility parameters, which can be used to assess stability reserve and compatibility.  
5.2 A blend is considered stable when the blend’s peptizing power is higher than the blend’s maximum flocculation ratio;3,4 both of them can be calculated using empirical blend rules. Refineries and terminal owners can prevent the flocculation of asphaltenes due to incompatibility by assessing the compatibility of fuels beforehand.
Note 4: See Appendix X1 for an example of prediction of compatibility.
SCOPE
1.1 This test method covers a procedure for quantifying the maximum flocculation ratio of the asphaltenes in the oil and the peptizing power of the oil medium, by an automatic instrument using an optical device.  
1.2 This test method is applicable to atmospheric or vacuum distillation residues, thermally cracked residue, intermediate and finished residual fuel oils, containing at least 1 % by mass asphaltenes. This test method has not been developed for asphalts.
Note 1: An optical probe detects the formation of flocculated asphaltenes. The start of flocculation is interpreted when a significant and sustained increase in rate-of-change of signal, as measured by the optical probe, ensures flocculation is in progress. The start of flocculation can be detected unambiguously when the sample contains at least 1 % mass asphaltenes as measured by Test Method D6560.
Note 2: This test method is applicable to products typical of Specification D396—Grades 5L, 5H, and 6, and Specification D2880—Grades 3-GT and 4-GT.  
1.3 This test method was evaluated in an interlaboratory study in the nominal range of 32 to 76 for the maximum flocculation ratio and in the nominal range of 36 to 95 for peptizing power.
Note 3: The nominal range is determined by (min. sample mean—Reproducibility) to (max. sample mean + Reproducibility).  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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 basis for the estimation of the oxidation stability of middle distillate fuels such as No. 2 fuel oil.  
5.2 The test method may not provide a prediction of the quantity of insolubles that will form in field storage over any given period of time. The amount of insolubles formed in such field storage is subject to the specific conditions which are too variable for this test method to predict accurately.  
5.3 Test Method D2274 yields results more rapidly than Test Method D4625, the 43 °C bottle test. However, as a result of the significantly elevated temperature and the pure oxygen atmosphere, the nature and amount of insolubles may deviate to a greater extent than Test Method D4625 from those formed in field storage.
SCOPE
1.1 This test method covers the measurement of the inherent stability of middle distillate petroleum fuels under specified oxidizing conditions at 95 °C.
Note 1: Fuels used in establishing the precision measures for this test method were described as gas oil, diesel fuel, No. 2 heating oil, and DFM, a Navy distillate fuel suitable for diesels, boilers, and gas turbines. (The term DFM is no longer used when referring to fuel meeting MIL-F-16884 requirements; rather it is called F76 as it conforms to NATO F76 requirements.) While the test method may be used for fuels outside the range of these fuels, the precision measures may not apply.  
1.2 This test method is not applicable to fuels containing residual oil. This test method has not been validated for testing biodiesel, such as meeting Specification D6751 or blends of middle distillates and biodiesel, such as meeting Specification D7467, or both. Test Method D7462 has been determined to be suitable for testing B100 and all blends of middle distillates and biodiesel.
Note 2: No. 1 and No. 2 grades in Specifications D396 or D975 currently allow up to 5 % biodiesel meeting Specification D6751. Samples containing biodiesel can result in partial dissolution or compromise of the membrane filter and give erroneous results.  
1.3 The values given in SI units are to be regarded as the standard. The values in parentheses are for information only.  
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 induction period may be used as an indication of the tendency of motor gasoline to form gum in storage. It should be recognized, however, that its correlation with the formation of gum in storage may vary markedly under different storage conditions and with different gasolines.
SCOPE
1.1 This test method covers the determination of the stability of gasoline in finished form only, under accelerated oxidation conditions. (Warning—This test method2 is not intended for determining the stability of gasoline components, particularly those with a high percentage of low boiling unsaturated compounds, as these may cause explosive conditions within the apparatus. However, because of the unknown nature of certain samples, the pressure vessel assembly shall include a safety burst-disc in order to safeguard the operator.)
Note 1: For measurement of oxidation stability of gasoline by measurement of potential gum, refer to Test Method D873, or IP Test Method 138.
Note 2: The precision data were developed with gasolines derived from hydrocarbon sources only without oxygenates.  
1.2 The accepted SI unit of pressure is the kilo Pascal (kPa), and of temperature is °C.  
1.3 WARNING—Mercury has been designated by many regulatory agencies as a hazardous substance that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Use Caution when handling mercury and mercury-containing products. See the applicable product Safety Data Sheet (SDS) for additional information. The potential exists that selling mercury or mercury-containing products, or both, is prohibited by local or national law. Users must determine legality of sales in their location.  
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 induction period may be used as an indication of the oxidation and storage stability of spark ignition fuel.  
5.2 Compared to some other oxidation and storage stability test methods, this test method uses a small sample and gives a result in a short time period.
SCOPE
1.1 This laboratory test method covers the quantitative determination of the stability of spark ignition fuel, including those containing alcohols or other oxygenates, under accelerated oxidation conditions, by an automatic instrument (Warning—This test method is not intended for determining the stability of gasoline components, particularly those with a high percentage of low boiling unsaturated compounds, as these can cause explosive conditions with the apparatus.2)  
1.2 This test method measures the induction period, under specified conditions, which can be used as an indication of the oxidation and storage stability of spark ignition 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.  
1.4 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 induction period may be used as an indication of the oxidation and storage stability of middle distillate fuel.  
5.2 Compared to some other oxidation and storage stability test methods, this method uses a small sample and gives a result in a short time period.
SCOPE
1.1 This laboratory test method covers a quantitative determination of the stability of middle distillate fuels such as diesel fuels and heating oils, with up to 100 % biodiesel, under accelerated oxidation conditions, by an automatic instrument.
Note 1: This test method is technically equivalent to test method EN 16091  
1.2 This test method is designed for products complying with Specification D975 on Diesel Fuel, Grades No. 1D and 2D; Specification D396 on Burner Fuel, Grades No. 1 and No. 2; Specification D6751 on Biodiesel, B100, and Specification D7467 on Diesel Fuel Oil, B6 to B20.  
1.3 This test method measures the induction period, under specified conditions, which can be used as an indication of the oxidation and storage stability of middle distillate fuels.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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 procedure describes a rapid and sensitive method for estimating the stability reserve of an oil. The stability reserve is estimated in terms of a separability number, where a low value of the separability number indicates that there is a stability reserve within the oil. When the separability number is between 0 to 5, the oil can be considered to have a high stability reserve and asphaltenes are not likely to flocculate. If the separability number is between 5 to 10, the stability reserve in the oil will be much lower. However, asphaltenes are, in this case, not likely to flocculate as long as the oil is not exposed to any worse conditions, such as storing, aging, and heating. If the separability number is above 10, the stability reserve of the oil is very low and asphaltenes will easily flocculate, or have already started to flocculate.  
5.2 This test method can be used by refiners and users of heavy oils, for which this test method is applicable, to estimate the stability reserves of their oils. Hence, this test method can be used by refineries to control and optimize their refinery processes. Consumers of oils can use this test method to estimate the stability reserve of their oils before, during, and after storage.  
5.3 This test method is not intended for predicting whether oils are compatible before mixing, but can be used for determining the separability number of already blended oils. However, experience shows that oils exhibiting a low separability number are more likely to be compatible with other oils than are oils with high separability numbers.
SCOPE
1.1 This test method covers the quantitative measurement, either in the laboratory or in the field, of how easily asphaltene-containing heavy fuel oils diluted in toluene phase separate upon addition of heptane. The result is a separability number (%). See also Test Method D7061.  
1.2 The test method is limited to asphaltene-containing heavy fuel oils. ASTM specification fuels that generally fall within the scope of this test method are Specification D396, Grade Nos. 4, 5, and 6, Specification D975, Grade No. 4-D, and Specification D2880, Grade Nos. 3-GT and 4-GT. Refinery fractions from which such blended fuels are made also fall within the scope of this test method.  
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 ...
SCOPE
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 mm2 s-1 and heavy and residual fuels with kinematic viscosities (at 40 °C) of ≤700 mm2 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 Bar...

SIGNIFICANCE AND USE
5.1 Automatic determination of stability parameters using a light back-scattering technique improves accuracy and removes human errors. In manual testing, operators have to visually compare oil stains on pieces of filter paper to determine if asphaltenes have been precipitated.  
5.2 Refinery thermal and hydrocracking processes can be run closer to their severity limits if stability parameters can be calculated more accurately. This gives increased yield and profitability.  
5.3 Results from the test method could be used to set a standard specification for stability parameters for fuel oils.  
5.4 The compatibility parameters of crude oils can be used in crude oil blending in refineries to determine, in advance, which crude oil blends will be compatible and thus can be used to minimize plugging problems, unit shut downs, and maintenance costs. Determination of crude oil compatibility parameters also enables refineries to select crude oil mixtures more economically.  
5.5 This test method can measure stability and compatibility parameters, and determine stability reserve on different blends for particular applications to optimize the blending, storage, and use of heavy fuel oils
Note 1: Users of this test method would normally use stability and compatibility parameters to determine stability reserve of residual products, fuel blends and crude oils. However, the interpretation of stability, stability reserve and compatibility is heavily ‘use dependent,’ and is beyond the scope of this test method.
SCOPE
1.1 This test method covers an automated procedure involving titration and optical detection of precipitated asphaltenes for determining the stability and compatibility parameters of refinery residual streams, residual fuel oils, and crude oils. Stability in this context is the ability to maintain asphaltenes in a peptized or dissolved state and not undergo flocculation or precipitation. Similarly, compatibility relates to the property of mixing two or more oils without precipitation or flocculation of asphaltenes.  
1.2 This test method is applicable to residual products from atmospheric and vacuum distillation, from thermal, catalytic, and hydrocracking processes, to products typical of Specifications D396, Grades No. 5L, 5H, and 6, and D2880, Grades No. 3-GT and 4-GT, and to crude oils, providing these products contain 0.05 mass % or greater concentration of asphaltenes.  
1.3 This test method is not relevant to oils that contain less than 0.05 % asphaltenes, and would be pointless to apply to unstable oils that already contain flocculated asphaltenes.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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 describes a sensitive method for estimating the intrinsic stability of an oil. The intrinsic stability is expressed as S-value. An oil with a low S-value is likely to undergo flocculation of asphaltenes when stressed (for example, extended heated storage) or blended with a range of other oils. Two oils each with a high S-value are likely to maintain asphaltenes in a peptized state and not lead to asphaltene flocculation when blended together.  
5.2 This test method can be used by petroleum refiners to control and optimize the refinery processes and by blenders and marketers to assess the intrinsic stability of blended asphaltene-containing heavy fuel oils.
SCOPE
1.1 This test method covers a procedure for quantifying the intrinsic stability of the asphaltenes in an oil by an automatic instrument using an optical device.  
1.2 This test method is applicable to residual products from thermal and hydrocracking processes, to products typical of Specifications D396 Grades No. 5L, 5H, and 6, and D2880 Grades No. 3-GT and 4-GT, and to crude oils, providing these products contain 0.5 % by mass or greater concentration of asphaltenes (see Test Method D6560).  
1.3 This test method quantifies asphaltene stability in terms of state of peptization of the asphaltenes (S-value), intrinsic stability of the oily medium (So) and the solvency requirements of the peptized asphaltenes (Sa).  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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.