1、Designation:D797814Standard 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 oforiginal adoption
2、 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 field or in a laborat
3、ory 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-1and in fuel-assoc
4、iated 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,fungi,and fungal
5、 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 example,these value
6、s 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 included in thisstandar
7、d.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Doc
8、uments2.1 ASTM Standards:3D975 Specification for Diesel Fuel OilsD1129 Terminology Relating to WaterD1655 Specification for Aviation Turbine FuelsD4175 Terminology Relating to Petroleum,PetroleumProducts,and LubricantsD4176 Test Method for Free Water and Particulate Contami-nation in Distillate Fuel
9、s(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 Fuels,As-sociated Materials and Fuel System Component
10、s 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-tent of Fuels and Fuel Components Boiling Below 3
11、90CFiltration 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 Implementation of Avoidanceand Remedial Strategies,2nd Editi
12、on,2008,EnergyInstitute,London,ISBN 978 0 85293 524 82.3 Other Standards:ISO 8217 DMA Petroleum Products,Fuels(Class F),Speci-fications of Marine Fuels,4th Edition 2010,ISO Switzer-land1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants
13、and is the direct responsibility ofSubcommittee D02.14 on Stability and Cleanliness of Liquid Fuels.Current edition approved Dec.15,2014.Published February 2015.DOI:10.1520/D7978-14.2Defense Standard 91-4,Fuel,Naval,Distillate(NATO Code:F-76,JointService designation DIESO F-76),Issue 9,3 May 2013,UK
14、 Defense Standardiza-tion3For referenced ASTM standards,visit the ASTM website,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 C
15、avendish St.,London,WIG 7AR,U.K.,http:/www.energyinst.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 IATA Guidance Material on Microbiological Contaminationin Aircraft Fuel Tanks,4th Edition,December 201153.Terminology3.1 Definitions
16、For definitions of terms used in this testmethod,refer to Terminologies D1129,D4175,and E2756.3.2 Definitions:3.2.1 colony,na discreet visible aggregate of microorgan-isms that develops when a viable microorganism,or particlecontaining viable microorganisms,is introduced into a gel-based nutritive culture medium and reproduces there.3.2.1.1 DiscussionA period of incubation is necessary toallow sufficient reproduction.This test method utilizes areactive compound that shortens the time for colonie
