1、Designation:D797814(Reapproved 2019)Standard Test Method forDetermination of the Viable Aerobic Microbial Content ofFuels and Associated WaterThixotropic Gel CultureMethod1This standard is issued under the fixed designation D7978;the number immediately following the designation indicates the year of
2、original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method describes a procedure that can be usedin the fiel
3、d or in a laboratory to quantify culturable,viableaerobic microorganisms present as contaminants in liquidfuels,including those blended with synthesized hydrocarbonsor biofuels,with kinematic viscosities(at 40 C)of 24 mm2s-1and heavy and residual fuels with kinematic viscosities(at40 C)of 700 mm2s-1
4、and in fuel-associated water.1.1.1 This test method has been validated by an ILS for arange of middle distillate fuels meeting Specifications D975,D1655,ISO 8217 DMA,and NATO F-76.21.2 This test method quantitatively assesses culturable,viable aerobic microbial content present in the form ofbacteria
5、,fungi,and fungal spores.Results are expressed as thetotal number of microbial colony forming units(CFU)/L offuel or total number of CFU/mL of associated water.Thenumber of CFU should not be interpreted as absolute valuesbut should be used as part of a diagnostic or conditionmonitoring effort;for ex
6、ample,these values can be used toassess contamination as absent,light,moderate,or heavy.NOTE1This test method is technically equivalent to IP 613,althoughthe two methods are not currently jointed.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are includ
7、ed in thisstandard.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitation
8、s prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization Techni
9、calBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:3D975 Specification for Diesel FuelD1129 Terminology Relating to WaterD1655 Specification for Aviation Turbine FuelsD4175 Terminology Relating to Petroleum Products,LiquidFuels,and LubricantsD4176 Test Method for Free Water
10、and Particulate Contami-nation in Distillate Fuels(Visual Inspection Procedures)D6469 Guide for Microbial Contamination in Fuels and FuelSystemsD6974 Practice for Enumeration of Viable Bacteria andFungi in Liquid FuelsFiltration and Culture ProceduresD7464 Practice for Manual Sampling of Liquid Fuel
11、s,As-sociated Materials and Fuel System Components forMicrobiological TestingD7847 Guide for Interlaboratory Studies for MicrobiologicalTest MethodsE2756 Terminology Relating to Antimicrobial and AntiviralAgents2.2 Energy Institute Standards:4IP 385 Determination of the Viable Aerobic Microbial Con-
12、tent of Fuels and Fuel Components Boiling Below 390CFiltration and Culture MethodIP 613 Determination of the Viable Aerobic Microbial Con-tent of Fuels and Associated WaterThixotropic GelCulture MethodGuidelines for the Investigation of the Microbial Content ofPetroleum Fuels and for the Implementat
13、ion of Avoidance1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.14 on Stability,Cleanliness and Compatibility of Liquid Fuels.Current edition approved July 1,2019.Published August 2
14、019.Originallyapproved in 2014.Last previous edition approved in 2014 as D7978 14.DOI:10.1520/D7978-14R19.2Defense Standard 91-4,Fuel,Naval,Distillate(NATO Code:F-76,JointService designation DIESO F-76),Issue 9,3 May 2013,UK Defense Standardiza-tion3For referenced ASTM standards,visit the ASTM websi
15、te,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.4Available from Energy Institute,61 New Cavendish St.,London,WIG 7AR,U.K.,http:/www.energyinst.org.Copyright ASTM Int
16、ernational,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 and Remedial Strategies,2nd Edition,2008,EnergyInstitute,London,ISBN 978 0 85293 524 82.3 Othe