ASTM D8070-23 PDF

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...